Thursday, December 22, 2011

Recording the Show: Redux

I do a choral show a couple times a year and I usually take a recording off the board as a favor to some friends of mine in the chorus. I always caution them that what the board hears is not what the audience hears. I don't tell them that setting up to do the recording, and cleaning up the results, takes quite a bit of time.

The needs of a live show and a recording are largely orthogonal. In a large venue, you can split the feeds (which you are going anyhow for the sake of Monitor Beach). And everything is mic'd anyhow. In a small space, a good part of the act is acoustic -- which means a lot of the performance never gets close enough to a microphone to get captured by it. And in a small intimate space, you don't want to be sticking microphones in front of everyone and everything.

Well, I just got done working a show in which recording was intended from the start. As it happens, I put a very, very little bit of the vocal microphones into house speakers. But basically the audience was on its own; they were getting the concert through air, not through wires.

The downside is I basically had to do this with my own small assortment of gear.

Presonus Firewire as the main A/D converter. That's only 8 channels. Using the ability of the Mac platform's Core Audio to create an Aggregate Device, I added another two channels from the line in. I also set up a second laptop, with a USB recorder as back-up, taking 48/24 audio (96/32 kept crashing) from a flying, mix-as-you-go stereo mix-down.

Over a long brunch at a local cafe I made up a channel plan. This was a chorus. I knew they had a keyboard. I planned ahead for bass and drums even though no-one had told me about them. A day before the performance I found out the keyboard wasn't electronic; it would be a baby grand.

Same difference. The rough plot was all stereo busses, sent to the hard disk recorder as five pairs; two chorus mics, two piano mics, a stereo mix-down of the drum mics, and a pair of mics set up at a distance.

During the tech I found out they also had a violinist, and the band was all playing percussion toys for one number. So I added an omnidirectional mic in the middle of the band area, and a violin mic. I also saw a number of places in which one member of the chorus would come forward to do a solo, and, concerned about localization (with them passing between the choral mics) I added a stand mic in the center.

Since I didn't have the spare record channels I mixed the center mic into the stereo bus of the choral mics, and the violin mic into the stereo bus of the piano. I figured if the added signal got too hot, I could always invert one of the channels to sum the center out. Of course, there is no similar trick for boosting the center...!

So already I was being a little foolish and trying to hold on to elements of the original plan that weren't working. After two performances I bit the bullet and re-configured. Since the stereo piano mic'ing wasn't working anyhow I took that down to a single mono channel. That freed up a channel for the violin. And since the drums were hardly playing (and it wasn't that great a kit anyhow) I gave up on stereo drums and also summed that to mono. That gave me a spare channel to isolate the center vocal mic.

Because as the concert progressed and I was doing my stereo mixes, I found there were several places where I needed that center mic to be on its own. So it made sense to pull it out of the bus.

I switched the direct audio in for the USB connection and better A/D converters of an Ozone, but the Mac had trouble with the end of the concert I discovered the rear mics had not been captured in the multitrack. Switched back to the Mac's own input jack. A videographer showed up, and they adjusted some of the lights. Final concert. Something in that changed setup was now sending dimmer hum into my rear microphones every time the lights changed.

Well, SoundSoap seems to have gotten rid of the worst of the hum (at a noticeable drop in quality however). And now I can finally work on the multi-tracks and see if the choices I finally gave myself are going to let me mix the show the way I want it.

(And, actually, the 10 tracks of recording wasn't the worst limitation. I barely had that many microphones that were worth using, and I used up all of my personal cable and most of the house cable to boot just connecting them. Plus that basically maxed out the board -- once you added stereo house feed, three reverbs, and a monitor feed. I think I had two outputs I wasn't using, in addition to the S/PDIF which -- as it turns out -- can only be switched on if you are using a PC to record from. The Mac version of the driver never got around to including that button -- not on that model, anyhow.)

MIDI and the Arduino : Part II

Now we start to get complicated. Before we can move on from "Hello (MIDI) World," however, we need to understand a little more about what we are dealing with.

Turn the Way-Back Machine to the early 80's and the rise of synthesizer-based music. Yamaha was riding high on their flagship DX-series FM synthesizers, and Roland was moving in fast with LAS -- the first of the true sample-manipulation synthesizers that now dominate the virtual instrument market. And over several meetings, the leading electronic instrument manufacturers got together to talk about integration; about a single standard to allow machines to communicate with each other.

Dave Smith was the pioneer here. He introduced his fledgling "Musical Instrument Digital Interface" at AES in 1981, and by the 1983 NAMM show he was able to demonstrate a connection between one of his own Prophet synths and a Roland JP-5.

MIDI came out of the speculative academic environment of experimental music; out of a background that was re-thinking the shape of interfaces (such as Don Buchla's unique controllers), the role of the synthesizer in music (from Wendy Carlos to Kraftwerk), even the role of the musician (Brian Eno building on the work of John Cage and others). This heady experimental atmosphere led, I believe, to the construct of MIDI as an open-ended and extensible language.

It would have been so easy to make MIDI dogmatic; to restrict it, for instance, to only describing events within the beat and tempo parlance of Western music. (And, yes; working with microtonal music is not quite as transparent as it could be in MIDI!) But, still, the very simplicity of what the language provides allows it to flexibly encompass all manner of events that might not otherwise be encompassed.

MIDI does not describe sound. It describes events. Although there are additions to the language that can specify timbres more closely, or even load in samples, interpretation of the events is still up to the machine receiving the MIDI message. It is sheet music for computers.

This also makes it extremely flexible for other uses. In my current MIDI-controlled servo for instance, noteOn is interpreted as a command to move, to a position specified by the note number, and at a slew rate specified by the velocity.

The MIDI specification -- as it has been amended and expanded over the years by the MIDI consortium while still maintaining full backwards compatibility -- includes as do most connection protocols a hardware layer and a software layer.

The heart of the traditional MIDI hardware is the opto-isolator. MIDI gear is designed so the OUT port of one piece of equipment drives an opto-isolator behind the IN or THRU port of the next piece of gear. An opto-isolator is an LED stuck in a black box with a photo-transistor. This isolation means there can never be a ground loop between pieces of MIDI gear*, and any voltage spike will blow out a $2 part instead of the whole synthesizer.

*technically. Standard practice is to ground the shield/pin 2 at the transmitter side, with the other end of the cable ground left unconnected, but not all manufacturers follow suit.

Before you make any electronic connection to a piece of MIDI gear, remember this; the IN port is expecting the voltage to drive an LED (5v TTL; it is expecting 3-5 volts for a "1" and 0-2 volts for a "0.") The OUT port is expecting to see the load of a a small LED. So don't connect a motor to a MIDI OUT port and expect it to run for very long before something breaks! (According to the spec, the current in the loop should be 5 mA. Most gear is capable of sinking somewhat more than that.)

The only two pins connected on the 5-pin DIN connector (a connector type standardized by the Deutsches Institut für Normung) are pins 4 and 5. Polarity matters, because like all LEDs the opto-isolator is one-way.

The rest of the physical layer is, and I paraphrase Wikipedia on this: A simplex digital current loop electrical connection sending asynchronous serial communication data at 31,250 bits per second. 8-N-1 format, i.e. one start bit (must be 0), eight data bits, no parity bit and one stop bit (must be 1).

Actually, the take-home here, besides the fact that communication is simplex and asynchronous (aka one-way, with no shared clock signal or other handshake needed), is that the normal state of the system is digital 1 -- which corresponds to no current flow.

When the system encounters current it calls that a start bit (the 0), and then parses an 8-bit word starting with the first edge it encounters. Technically, you could sleep the transmitter for quite some time between words, as each byte sent is uniquely interpreted.

As it happens, 8-N-1 is the default of the built-in UART on the AVR at the heart of the Arduino, therefor the serial out on the Arduino naturally sends the correctly formatted signal. All that is necessary to get an Arduino to send a bitstream that will be interpreted as a potential MIDI message is to set the BAUD rate to 31250 (which is easily done within the Arduino IDE via the "Serial.begin(31250);" init.)

On the receiver side, it is technically possible to connect the Arduino's serial port, but it is strongly not recommended. An opto-isolator will provide a lower current drain for the transmitter and protect the Arduino as well. Plus the physical layer assumes you are inverting anyhow. I'll get into how to wire the opto in a bit here.

Because of the simplicity of asynchronous simplex it is entirely possible to bitbang an acceptable MIDI message on an AVR without a built-in UART. That's basically what Software Serial does anyhow. I'll be documenting my experiments in bitbanging MIDI from cheap through-hole AVRs in the future, but for now just ignore all that stuff about framing bits and parity and just think of MIDI messages as a series of ordinary 8-bit words.

8 bits are a byte. 8 bits are enough to do simple ASCII (not expanded ASCII). It also works out to 2 characters in hexadecimal. And reading "0Fh" is a lot easier than reading "00001111b." For technical and historical reasons MIDI is generally documented in the terms of hex pairs. If you are going to get down and dirty with MIDI commands, you have to get used to switching back and forth between hex, decimal in 0-9 and 1-10 formats, and a bit of binary now and then.

The format of almost all MIDI messages is "Opcode Data (Data) (Data)...."

In the case of the ubiquitous NoteOn message, this works out as;

First byte; "NoteOn for channel 15"
Second byte: "for the F# above Middle C"
Third byte: "with a velocity of 127."

Messages come in all different lengths. The System Exclusive message, for instance, can be multiple megabytes of data -- as long as it is bracketed by "System Exclusive Begin" and "System Exclusive Ends" (which includes a check-sum).

System Exclusive, by the way, is one of the open message formats that made MIDI so readily expandable. (Another major one was NRPNs).

Just a reminder here. When we are working with a nice friendly platform like the Arduino, what that noteOn message above translates as is three consecutive one-byte integers. Think of it as;

Serial.print(159, BYTE);
Serial.print(66, BYTE);
Serial.print(127, BYTE);

And, yes, you can do exactly this and it will be interpreted as a legitimate MIDI message. The only reason to play around with variables is to give yourself the flexibility to actually compose useful messages.

MIDI is a channeled system. Although some of the opcodes are global (meaning they are addressed to all devices on the network), most messages are prefixed with the channel number. This allows multi-timbral performance off a single MIDI stream; channel 10 might be handling drum sounds, channel 1 a piano sound, channel 2 a bass, etc.

In the example code I gave in Part I, I arrived at the correct channel-designated opcode by adding the raw opcode (144 for noteOn) to the channel number. A different way of looking at this, however, is that the 16 possible channels are expressed using the last four bits of the first byte sent. The top four bits are the opcode.

Thus, a noteOn for channel 15 is 9h, Fh. Or 10011111 in binary -- 159 in decimal.

This is why thinking in hex pairs can simplify your work when you are dealing with channel messages; just remember the channel is the low nibble, and the opcode is the high nibble.

In the case of data bytes, the high bit is unused. This limits the possible values to 0-127.

Here's the opcodes in binary format as listed by the MIDI Consortium: MIDI Messages As I said, if you are going to work with MIDI in the raw form, expect to be going back and forth between hex, binary, and decimal a bunch!

Here would be a nice place to point out that not all devices interpret (or send) all MIDI messages. If you have your hands on a manual, there will be a couple of sheets in the back, around the index, that specify what messages are used by that device.

So now that you know how to make a connection to the physical layer, and you've seen how to format a message in the software layer, it should be fairly straightforward to write software routines that send useful signals.

In one of my recent projects I needed to compose just a simple "Go" command in MSC (MIDI Show Control, an expansion of the basic MIDI 1.0 spec for use in theatrical applications). Instead of writing something elegant in software I just wrote a stack of Serial.print commands, each containing the actual binary needed;


For the four-button remote control MIDI device I was using for a time, the note number was determined by a scan of the open buttons, using a simple matrix;

for (button = 0; button<5; button++)
pressed[button] = digitalRead(inp[button]);
if (pressed[button] == HIGH)
noteOn(channel, button + 60, velocity);

That's a bit pseudo-code up there; don't use it as is.

Another necessary trick was polyphonics. What I did, was add a flag variable; sounding[button]. Whenever a noteOn was sent, I'd set the flag to know I'd already sent a note event for that button, rather than re-sending every time the loop polled the button status.

And that's long enough for this entry, except I want to make note of another peculiarity of MIDI messages. And that is Running Status.

Running status means that if you have sent the opcode for a noteOn event, you can follow it with more than one data pair and they will be interpreted as additional notes. This is extremely useful for continuous controller messages, which otherwise would be rather longer.

The format here is;

Opcode (noteOn channel n)
status1 (note)
status2 (velocity)
status1 (another note)
status2 (the velocity for that second note)
etc., etc.

The receiving device will continue to accept these as noteOn events until it sees a new opcode.

And now it becomes clear why all opcodes have a leading "1," whereas all data bytes have a leading "0"!

Aphorisms Again

Do not denigrate the benefit of looking like you know what you are doing.

First off, show business is a stressful business. The actors and musicians, not to mention the directors and producers, have a lot on their shoulders. So don't add to their tension by making them doubt the sound will work. Keep your doubts to yourself. You know the solutions you came up with are compromises. But the actor doesn't need to be thinking about that when they are on stage.

Of course looking like you know what you are doing is nice from a business standpoint as well.

Looking like you know what you are doing is nice for the audience, too. It makes them feel as if they are in good hands, and will be presented with a worthwhile night's entertainment. That is, assuming you deliver! Otherwise you risk having them think to themselves, "All of this equipment, and the sound still sucks."

Don't underestimate the placebo effect. Sometimes an audience member may wonder if they are hearing the third guitar. And they'll glance at the microphone set up in front of it and decide that they must be. What they don't know is that the guitar sounded horrible or the mic blew a gasket or for whatever other reason it isn't connected to the sound system. But you leave it up there because it looks cool, and it convinces the guitar player and his friend in the audience that you are serving him.

Don't get me wrong. I'm not advocating dishonesty. But in most cases, expressing more confidence than you have is a good thing. We are engineers, after all. Engineers know how many things can go wrong. But from a statistical standpoint, the sound will probably work. So you burden yourself with the fears of all those things you know about and no-one else does. And let the performers get on with the task of worrying about the things they know about.

Escape the temptation of perfect optimization.

Very few problems ever have a perfectly optimal solution. You can go crazy -- and you can waste a whole lot of time -- weighing too-similar alternatives. Just pick one and commit to it. Any loss you suffer because the alternative actually was slightly better will be, in most cases, completely offset by the time you saved by going ahead anyhow.

No plan survives first contact with the enemy. But the right plan will keep you alive long enough to come up with a better one.

Recognize that what you intended to do is not what you will finish up with. When you finally see the real set, when you finally hear the actual band, you may realize a lot of your work was unnecessary. So be it. It is foolish to try to hold on to work that isn't needed anymore, and even more foolish to search for justifications of why you still need it. It is also, more subtly, foolish to blame yourself for wasting time. If you front-loaded the work as much as possible, you wasted that time when there was more of it available to waste. And, beside -- you learn as much if not more from what didn't work, as you learn from what did.

The trick is to stay flexible, to not get too emotionally attached to what you thought you were going to do. And to design in such a way so you will have that flexibility when you need it.

This happens through doing many things, large and small. Document, and self-document; when you have to make a quick improvisation, it helps immensely if you can figure out what the existing system does. If you need to grab a cable quick to use somewhere else, you really, really want to know you are grabbing the right one; the one you no longer need.

Piling everything up in one huge mass with no labels and no organization and no documentation sets you up for failure in every case but the rare one when the event actually does unfold exactly the way you expected it to.

Have spares. When you are under the stage, run a second cable just in case. When you are running a power line, break it out with a strip just in case you need to plug something else in there. When you run out cable, dress the slack at the business end, just in case you have to move the microphone. Cover your bases, and anticipate having to make changes.

You can't use the air above you, the runway behind you, or the fuel that's back in the truck.

Bring all the gear to the gig. It's always the one piece of gear you were sure you didn't need, that you do.

Leave a spare snake cable. Test the mics before the curtain opens. Load in the night prior if they give you a night prior; don't count on getting it all done at the last minute.

You get the picture.

Tuesday, December 20, 2011

MIDI and the Arduino : Part I

I am intending to do a series of in-depth posts about how you can do MIDI on your Arduino or AVR. It may take me a while, though; I have a show up this week and four more already in meetings.

This post, then, is about getting to "Hello, World."

To be precise, it is about basic output from Arduino via the MIDI hardware level.

First the hardware. I can not do better than this schematic from the Arduino Playground itself.

The connector is a five-pin din. In the MIDI world, unlike most audio cables, all jacks are female and all cables are male. Even though it is a five-pin connector, only three of the connectors are actually used.

If your local electronics supplier does not have them, and you don't want to order online you can always cut a short MIDI cable in two and make a tail from it.

The 220 ohm resistor (color band code red-red-brown) is the only passive component you need. Actually, you can do without, but it is a lot safer with it (the risk is blowing the opto-isolator in the MIDI gear you are connecting to.)

And that's the physical layer.

On the software side, MIDI Library 3.1 is at SourceForge, with a small tutorial at the official Arduino website.

Of course I wrote my own, much simpler library. All I needed was output. I'm going to try to comment my way through an example here with as little actual explanation as possible:

int channel = 0;
int note = 60; // these set up default values for the later function
int velocity = 100; // in case the code doesn't specify any

void setup()
Serial.begin(31250) /* this is a key line; we are using the Arduino's serial port but it has to be set to the BAUD rate of MIDI in order for ordinary MIDI devices to see it. */

void loop()
noteOn(channel, note, velocity); //here's the function call
noteOff(channel, note, velocity);
delay(2000); /* the way I set this up, there is no test condition for the noteOn and noteOff events; once the program has initiated it cycles endlessly, sending out a note with the default values every few seconds. */

void noteOn(char channel, char note, char velocity)
Serial.print(channel + 144, BYTE);
Serial.print(note, BYTE);
Serial.print(velocity, BYTE);

/* okay, this takes a little explanation. First, the "char" and "BYTE" nonsense is my (sloppy) way of forcing type conversion. It's a C thing; if you specify the kind of integer inside a statement like this, it creates and uses an image of that integer that is truncated or otherwise fit into the specified type. Weird stuff can happen with type forcing, though. The advantage here is that I'm able to state the note number and velocity the way most MIDI players will present them; as a number from 0 to 127 (middle C is 60). When you get into more complex commands it often helps to think of them in hexadecimal pairs (which is how they are presented in the index of most MIDI hardware).

The (channel + 144) has to do with how MIDI messages are constructed. The first byte sent is always a command (or part of a command). Since noteOn messages are not global, they are sent individually to any of the 16 possible channels given by the MIDI specification. Thus "144" indicates "noteOn event for channel 0," and "159" would indicate "noteOn event for channel 15."

(Yes...within the actual data stream we count from 0. Most of the front panel of your MIDI device will count from 1, however, thus channels 1 through 16 instead of channels 0 through 15.)

A noteOn message creates an expectation by the receiver that it will be followed by two more bytes of information, specifying the note number and the velocity. */

void noteOff(char channel, char note, char velocity)
Serial.print(channel + 128), BYTE);
Serial.print(note, BYTE);
Serial.print(velocity, BYTE);

/* This function stops the note. In MIDI, unless the device is a drum machine or something else that plays a single sample and stops, the note requested will continue to play until the device is asked to stop that note -- or until an AllOff command -- a system-wide command -- is received.

There are two ways legitimized in the MIDI spec for stopping a note; one is to send a noteOff command for the same channel and note number. Cut-off velocity is interpreted by some MIDI instruments but most of them ignore it. The other way is to send a noteOn event with a velocity of 0.

This latter can really mess you up when you are using a keyboard to trigger an external effect, by the way! You have to insert a filter to trap all "noteOn" events with velocities of 0 so they don't cause false triggers. */

And that's it. The above was hand-typed, and I can't guarantee it against typos.

In practice, of course, your software will be testing some condition -- a sensor trip or button press -- and sending out various kinds of MIDI signals with the defaults replaced by, say, a different note number for each button pressed or for the intensity of light falling on a photocell or whatever.

But I need to say something even more basic here. This is, as I stated in my Thompsonian "To be precise;" above, is MIDI output on using the hardware standard.

That is, this is how to send a signal from an Arduino that will go down a MIDI cable, into the MIDI IN connector on a MIDI device, and be interpreted as a command.

Which is to say; the above will play a note on a keyboard or a drum machine, can be used to trigger a cue in Qlab (given a MIDI input connected to the host computer), and may do strange things with a lighting console or sound board or DJ laser display that has a MIDI input jack.

And lastly, this is not the simplest option. The simplest option is a MIDIsense board from Lady Ada, or a MIDI shield from SparkFun Electronics. Both of these options come with tested libraries in addition to the complete hardware. Lady Ada's framework has the advantage of being able to adjust via software on a host computer the sensitivity and response curve of sensors you attach to the board. Plus it even includes a 9V battery compartment for on-the-road use! The SparkFun board is cheaper and faster to set up, and includes buttons and pots to mess around with. Both, of course, include the opto-isolator of a MIDI-in port -- which is the subject for a later entry here.

Part II is here:

Location, Location, Location

I've got a couple of challenging shows coming up that are making me rethink the old "A B" paradigm of vocal reinforcement. And that has also led me to review some of what I think I know about speaker and microphone placement.

First off, let's re-iterate; location matters. In microphones, if you put the right mic in the right place your mix will be almost done. The wrong mic in the wrong place? You mix is all but done for. In reality, of course, the position you wanted is occupied by a music stand, or the mic just isn't in inventory. And in the middle of the show the bass forgets to plug in, the tripod starts to droop, and the conductor kicks out a cable while striding to the podium. And you end up having to do horrible, horrible things with EQ just to try to eke some semblance of sound from the wrong mic that's in the wrong place.

Oh, and the one caveat is drums. Most instruments, if you picked the right mic and placed it right, it will sound good when you fire it up. You may do a little gentle EQ to taste -- or more if you are having trouble seating it in the mix. Drums are among the exceptions; there, the expected sound is an artificial construct made of very close mics with savage EQ and all sorts of funny processing (companding helps a kick a LOT). Of course, you can get a wonderful drum sound with a single overhead, or a distant pair. The book trick is to have both of your pair equidistant from the snare, as that is the loudest mid-range element and the one where phase cancellation will show up the most.

In the case of wireless microphones, the forehead at the hairline is a natural sound (slightly thin and distant, but very real sounding.) The cheek position, from ear all the way to corner of the mouth, require drastic EQ to make them sound good. They also pick up a lot more mouth noise, breath noise, and handling noise. The lapel position is almost the worst of them. Far enough down, it will be fairly natural (with a huge shadow in the EQ from the cavity under the chin) but it also shifts level with every head movement. The higher the lapel position gets, the worse it is; those women who show up in turtlenecks or high-collar blouses and try to clip to the neck line demonstrate just what happens to a poor microphone when it goes deep within the shadow of the chin. It sounds a bit like the speaker is inside a 55 gallon plastic storage drum.

The "right position" and the "right mic," of course, depends on the style of music, the style of the performer, and the needs of the mix -- whether, for instance, you are reinforcing a live band, or whether you are trying to do a recording session.

Classical violin, for instance, is best looking down from several feet above the face of the instrument. The same instrument played as a folk music fiddle is mic'd much closer. And you may chose to go more over the bow for more "hair" in the sound, or more over the bridge for a more natural tone. All of these are sculpturing decisions you make on the basis of what the musician sounds like, what the needs of the environment are, and what you have in your kit that day.

I'm about to mic a baby grand myself. I'm doing it primarily for recording, but it is before a live audience and that introduces constraints. It is set up right beside a drummer so that is a additional (large!) constraint. I am also a little unsure of the sound I want just yet; the group is oriented towards classical gospel and jazzy choral arrangements but what I heard in rehearsal from the piano was more straight-up classical piano. But with a very light hand. I look forward to seeing where she goes when she's behind the wheel of a baby grand (it could be very, very different from what I heard in rehearsal).

I'm also constrained on channels, and even more on available microphones. So I'm thinking strongly of trying a pair of small diaphragm condensers fairly tight in (I'm assuming I'll at least get the lid on long stick -- short stick will make this even harder). AT Pro37 on the right hand, about 6" back from the hammers and tipped towards the hammers as needed, and Shure PG81 (it's an SM81 at a cheaper price) over the bass strings, probably right at the cross, and tipped to almost 45 degrees towards the front of the piano. It's a variation on a scheme I've used before with some success.

I'll also get a fair amount of piano bleed in the omni condensor I'm sticking in the middle of the orchestra. And of course I have an ambient pair set up out in the audience -- a pair of old Oktava MK-012's is all I have available but at least there's a cute little ORTF bar to stick them on.

* * * *

Back from the gig. The piano mics didn't work as well as I'd hoped. It is a 5' baby grand with the lid on short stick. Not a lot of room to get in there, and the drums are right beside it. The piano sounded okay in what came through the leakage of the choral mics, though, so it isn't exactly critical to mic it for this show.

On the other hand the MK-012's on ORTF bar, up a full 12' on the sturdiest tripod I had, were very nice.

But back to location. The purpose of this blog entry is to talk about speaker location.

Speaker location for theater has two goals, goals which are largely orthogonal. The first is the "flat field"; bringing music and vocals to every member of the audience at acceptable volume and clarity. Since as FOH mixer you are basically stuck in one spot through the show, it helps the audience a great deal if most of the seats are hearing the same thing you are hearing. So you are trying very hard not to have the seats on the left hear more brass, the seats in the middle front hear more high end, and the seats in the rear of the house hear everything far too soft.

The other is placement of sounds, and for special effects particularly, what the Walter Murch coined as "Worldizing."

Take this last. To get a sound effect that sounds like it is coming from the hallway, put a speaker in the hallway. And even if you are recording; if you want a sound to sound like it happened in a bathroom, record or re-record it in a bathroom. The aim is to capture those subtle interactions that shape the perception of a space. And in the case of a theatrical setting, these subtle cues as a sound bounces around and filters out of an actual space on the stage will help make the sound believable.

Here's a simple example. Want a sound outside the windows? Don't stick a speaker facing the audience. Stick it on its back below the windows. The sound will bounce around and filter into the space.

The placement trick that started this essay, though, is in regards to vocal reinforcement.

I've had it work very well. For a production of "Master Class" I had the actress on a wireless mic for the memory sequences, and sent that to the house speakers. The sounds she remembered, of herself singing at la Scala, were played back from a pair of speakers in the wings aiming at and bouncing off a full-stage rear projection screen showing scenes from the opera house. The result was both placement, and extremely good isolation; the physical distance and the difference in sound qualities made it easy for the ear to focus on the speaker even as the singer was going all-out like only Callas can go.

The arrangement at many Broadway houses is an A-B system (or, most often, A-B-C). In the case of the pure A-B, the intention is to reduce the flanging effect of two open wireless microphones in close proximity. Thus each mic is routed to a completely different signal chain (bus, amplifier, speaker). As the show progresses actors are rotated into whichever group provides the fewest encounters.

What we do in smaller theaters is just the "C" part; the signal chain of orchestra and singer are different. Often, the orchestra is sent to a proscenium pair that provides some semblance of stereo imaging. The vocals are sent to a center cluster in mono. Again, the physical separation leverages the human ability to focus on one sound in exclusion of competing sounds, as long as there are sufficient cues to allow it to do so -- in frequency, time, or spacialization.

But the situation in a small house is not that simple. In a small house, there is direct acoustic energy from the stage. In one way this is your friend; with a little digital delay inserted into your reinforcement chain, the Haas Effect (also known as the Precedence Effect) helps the listener to localize the singer based on the first sound wave to hit them; the direct acoustic energy from the singer's mouth. If the system is set just right, you can get a good 10 dB of gain on that singer without it even being perceptible that they have a microphone (the human brain is very good at masking this sort of reinforcement from conscious perception).

The flip side is that the orchestra is also putting out direct sound, and enough to spoil any attempt towards localizing them in the house speakers. In fact, the band is putting out so much sound all by themselves you often have only a few bits and pieces in those speakers. And it gets worse if you try to ride the fader a little; all you do is change the levels of two or three instruments, throwing off the mix and the spacial placement all at the same time.

Plus, there's monitors. So another whole hunk of the volume in the audience is reflected sound from monitors, and you can't turn those down without hurting the singers and dancers ability to follow the music.

So, in the small house, your technically perfect (A/B)-C system ends up being different for every seat, and different from loud song to soft song as well.

So here's what I'm going to try over the next couple of shows. The first test case is a young cast and the band is just a small combo on stage. I'm going to eschew any band to the mains at all. I'm going to run a full band mix to monitors, but even for what would be the softer instruments -- such as electronic keyboard -- I'll provide them with band monitors so the sound level of each instrument is equal in the pit as well.

My aim is that the primary source will be either direct acoustics or the band's own monitors. Aka the orchestra itself will be the perceived source. Then I'll boost that subtly for the actors. If there is a wide dynamic range in the performance (soft solos versus large chorus numbers) I'll ride the monitor level by ear so as to raise the monitors for the benefit of the cast during the louder numbers.

The only thing the audience will hear is leakage. And there will be a lot of that, so I'm not worried on that account!

In the meantime I'll create a contoured reinforcement field using all available speakers; a mono system that is stronger towards the stage and tapers off pseudo-acoustically towards the rear of the house. With luck and tweaking I should be able to make the taper of this system similar to the taper of the band sound, thus maintaining the same mix ratio for all seats.

In the show following that, a 180 of sorts. It is going to be a loud show, rock oriented, with a semi-covered pit. I'm going to mic the orchestra and run it and the vocals hot. As a single mix; as if a rock song (the vocals will be panned center, of course.)* As much as is possible I'll run the reinforcement hot enough so it becomes a flat field out to the back of the house. The only downside to this is it will remove all localization cues from the actors themselves except for people sitting in the very front rows. Anywhere else, the actors will be heard almost entirely artificially, over the sound system. Basically I'm going to treat the place as if it was a 6,000 seat house and there was no direct stage sound.

* Stereo is a tough concept in typical theater settings. Except for a narrow aisle down the middle, most of the audience will be seated closer to one speaker than the other. Many will be so far on one side of the proscenium or the other the far speaker barely reaches them. So a hard-panned instrument or effect will be loud in one side of the audience, and unheard by the other. You can get away with this in effects, but it is murder on a mix. Imagine, if you will, half the audience hearing only the flutes and violins, the other half hearing only the brass and the cellos. Or one half hearing the right hand of the piano and the other half hearing the left.

Usually you reduce the stereo image; you avoid hard panning. If, on the other hand, you can score up a center cluster, then almost all of the audience is restored to hearing from two is just that one will have the whole mix, the other will have only half of it. And, again, half your audience hears a different band than the other half.

The temptation arises to pan a singer as they walk across stage. Trouble is, you are reinforcing them. That is; you've already decided their voice isn't loud enough for the audience. So by choosing to pan, you are adding more volume to the audience that already had it, and reducing volume to the half of the audience that's already further away from the singer. Not good.

Thursday, December 8, 2011


..Don't change a hair for me, not if you care for me... I'm getting burnt out on musicals. When I was designing lights and scenery more of my work was in straight plays (as well as trade shows and the like). But since I went mostly to the Sound side of the aisle ...there's a hole in the world like a great black pit... I've been working mostly musicals (with the odd live music show or graduation ceremony to break it up).

..Doors and windows, open and close... Over an average year I work -- as in actually sitting at the board mixing for each and every performance -- six to eight full musicals. ...and that's my new philosophy... The last one of those ...Easy Street; that's where we're going to be... was thirty-four performances. Add rehearsals and brush-up and dance calls ...these things you can not dispute, banana is the funniest fruit... and I hear each song through a good fifty times.

And this is mixing, mind you. ...high on the hill is a big old house with something dead inside it. Spirits walk the halls at night and make no effort now to hide it... So each and every song I'm listening intently, listening for any drop-out, trying to achieve a good vocal blend, ..fixing the roof, and raking the hay, is not my idea of a perfect day... and of course keeping track of where I am in the song so I can anticipate the chorus entrance and other fader moves. ...So I'm the king of the jungle... You can bet those songs get stuck in my head!

Add to this a good dozen shows I am consulting for, helping to load in, set up, can do it, you can do it if you try... and at least a half-dozen music shows which inevitably have a few songs from musicals's to the ladies who lunch... in them. time of day...

I am right now ...a paradox, a paradox... meeting on four shows ...there's a long thing winding staircase without any bannisters... and of course already listening to the music for those. ...never met a man I didn't like...

So not only is there plenty of opportunity ...notice me, Horton... to get songs from one show stuck in my head ...look at me, way up high... the fact that I'm somewhere in the process of multiple shows at once ...the Bronx is up and the Battery down... means the jukebox of my head gets rather crowded. ...everybody wants to be a cat...

I'm getting a little tired of it. ...the cow as white as milk the hair as yellow as silk... Pushing the faders on the board is a nice little combination ...where shining shine benignly drips... of constant tension and the cruel understanding that my best efforts will still not bring out the music the way I want it to be brought out. got to know the territory... And I'm getting particularly bored ...those magic changes... with pulling transmitters out of sweaty mic bags and dressing them with fresh batteries and condoms (and bits of electrical tape and moleskin). did you get to be you, Mr. Shepard...

Still ...Who's that hiding, in the tree top... I've got a pretty good gig now. It's not resident designer, ...they don't turn their head as they see me walk by... but it is as close to a steady gig as you'll ever get as a freelancer. So it's off to learn yet another set of songs ...what a glorious feeling, I'm happy again... until they, too, get stuck in my head.

Did I mention I work some of these shows more than once? I just closed my third "Annie," and not long before that was my fifth or sixth "Wizard of Oz," I also did "Producers" twice in one year, I've got my second or third "Grease" coming up, also did my second "Seussical" and my second "On the Town."

On the other hand, also was involved in "Merrily we Roll Along," "Into the Woods," "Pippin," and a couple of other surprisingly big standards for the first time. So there is always something new as well as something familiar, something peculiar, something......oh, darn it! And there I go again....

Tuesday, November 22, 2011

Not a Japanese Hand Tool experience

So I was starting some detail carving on the solid-body uke and I dropped by the hardware store to look for a spokeshave. They didn't have one, but I picked up a new chisel and a small plane, and a woodcarving blade for my Xacto knife.

And then, while getting some substitute brótchen at Acme, I realized I was in the neighborhood of Hida Tools. And, yes...I should have stopped there first. I should have remembered. Picked up a carving knife for under twenty bucks, and haven't touched the new chisel or plane since (the latter didn't work very well anyhow).

My first Japanese Tool experience must have been encountering a draw saw. And realizing instantly that cutting on the pull made so much more sense...ever since, ordinary wood saws have struck me as odd and backwards. Plus the thing was thin enough to trim off a dowel flush without cutting into the surface. And of course was gorgeous.

My next Japanese Hand Tools were hammer and niwatori. Nothing unusual about the hammer -- not a traditional Japanese style hammer, but just a mass produced steel framing hammer with a cushioned grip. Except for this; when I picked it up, it fell in line with my arm and as I gave it an experimental swing, the head was perfectly aligned. No need to twist the wrist and eyeball the head and compensate during the swing; it just fell into line with that perfect balance of a well-made weapon.

The big Japanese Hand Tool experience was actually with a new cooking knife. My old knife had finally died. I went to Hida and spent almost an hour trying to find one that was as close as possible to the same shape. Until the epiphany hit; trust the tools. So I stopped looking for what I thought a cooking knife should look like, and picked up what THEY thought a cooking knife should look like. And it, again, fell into my hand and I've been cooking with it since.

Of course the other side of Japanese Hand Tools is they are very fine, hand-made pieces of craftsmanship. You need to take care of them -- you don't just throw them into the tool box. The raw wood and metal need to be carefully oiled and treated lest they crack and rust. And they are also expensive. Hoo boy are they expensive!

And there's the side effect of getting sucked into a whole philosophy of woodworking, and traditional ways, and fine woodworking and theater props making are not exactly bed-fellows.

But you don't have to buy a set of finishing planes. You don't have to start learning how to hang shoji. You can select, generally towards the more mass-market (such as my hammer, which was not all that much more than a hammer from Sears), and towards those tools that are general-purpose and robust.

My new wood carving knife definitely falls into that category. I think I may be reaching for it as often as I reach for the venerable Xacto knife.

Friday, November 11, 2011

Rotating Outrage

Turns out that Stew-Mac has a Dremel router attachment.

Why is this significant? Because Dremel makes a plunge router attachment, a drill press attachment, a router table attachment......and all of them are absolute shit.

Apparently Dremel -- the most popular rotary tool out there, so much it is almost the "Xerox" (aka generic noun) for low-end rotary tools -- has decided that where their customer base is, is people who want to spend as little as possible for the illusion of having an all-purpose hand tool. This is a particularly strange attitude, particularly in that Dremel is the MacIntosh of low-end rotary tools; there are tons of cheaper ones available.

So, actually, what you are purchasing is the brand name. The sizzle, not the steak. The Dremels are cute, and you can find bits for them everywhere. They are also underpowered and overpriced. And they resemble not in the slightest a professional-grade tool with electronic speed control, or even a proper treadle.

Now, the tool itself, although overpriced, is functional. Within the design range; lots of people pick up one and expect to be able to cut lumber or do auto repairs or whatever. Forget it. Buy a full-sized, dedicated tool with a 1 3/4 horsepower motor if you are trying to hog through 1" hardwood or quarter-inch steel, or drive drywall screws all day, or otherwise intend some kind of actual construction task. Buy the Dremel for small projects and repairs and for models, guitar-making, and other crafts tasks that call for a smaller, more controllable tool than a thirty-five pound Porta-Cable.

But, still, why the shit accessories? The accessories are totally made of inappropriate cost-cutting. Spend ten bucks more on manufacture, and you could have metal instead of plastic, actual screws instead of friction stops, actual bearings instead of bearing surfaces.

What you get is the thing that makes me angry and sad every time I am in a modern hardware store. And that is; tools that offer the budget craftsman performance and return only wrecked work-pieces, more money to replace damaged tools and bits that wear out far too soon, and, oh yes, INJURIES.

Someone should walk up and slap the marketing asshole who so thinks so poorly of his customers he asks the design team only for bright and shiny, and who the hell cares about the poor person who ends up with the actual tool. And a second, harder slap for the engineer who permitted that design to pass, rather than resign and go to work for a company that didn't put the customer's sanity and fingers at risk.

What makes me saddest is to think of the people who are just starting out; young people, students, beginning DIY'er, retirees finally getting a chance to get into doing that inlay work they've always wanted time to learn. And not knowing that the fault isn't theirs. Not knowing that the reason their work sucks isn't because it is too hard to learn, or because they simply haven't the skill. But because they've been betrayed by the tool itself.

Sure, someone who has been around for a while can tell the tool is shit, and can compensate some. Right off the bat, one thing people do with these shit tools is throw away some of the plastic parts and build their own out of metal. It is also well worth, whenever you buy a cheap tool, to take it apart, file and emery-paper down the burrs the manufacturer never bothered to clean off, clean the paint overspill, properly lube it, and re-assemble to the proper torque.

And the ultimate case of this is people like Stewart-Mac. Who understand that the amateur or small luthier has a use for a Dremel-like tool -- that the 6" base Bosch is over-kill for slotting a bridge -- and have taken it upon themselves to build a router attachment the way that Dremel should have built it in the first place. Out of metal. With tolerances. With actual stop screws.

And they charge not all that much more than Dremel does for their sorry corporate-bottom-line driven insult-to-the-customer crap piece of plastic.

Sunday, November 6, 2011

Uke Out!

Six-show weekend just ended and maybe I can get back to projects before the next shows (or the next performances on the schedule) interfere again.

I'm still pretty enthused about my solid-body uke, although I am more realistic about how much it would cost and how long it would take, and more willing to put it on the back-burner while I work on paying work. I did figure out a couple new things, though:

The hardwood store in town has materials that will work. They even have some scrap wood that might be an even cheaper option. I'm tempted to grab five bucks of scrap (they price by the pound) just to get a feeling of how hardwoods like zebrawood and cordova or whatnot are like to work.

I will make a visit to TechShop SF to see what it looks like.

There actually IS a use for Ponoko in projects like this. Depending on how fine a cut you get, use a ShopBot or similar to CNC a 1/4" MDF template and use that to rout the body of your guitar. A router and template is the recommended shaping method anyhow, and it can be difficult to get a clean enough template with bandsaw and similar tools.

I've considered building a solid-body nylon string as well. An under-bridge pickup can be had for as little as $60. If nothing else, the lower string tension means I could purchase a pre-made traditional neck, and if it turned out to be too difficult to reinforce it, I could still use it to make a nylon string. This is in all ways a simpler construction process; traditional bridge instead of the more expensive metal bridge, etc., etc. Which might make it a better project to start out with!'s the design I came up with for the steel string:

The first step will be building a mock-up to test the ergonomics. It may need to be extensively re-thought in order to be fully playable. The design actually came out of a process of abstracting and cartooning the shape of a traditional ukulele. On one of my sketches, the "pinch" of the hourglass had completely fallen away, and the resulting teardrop had an intriguing look to it.

I'm hoping the end result looks like an instrument coming out of a long but unfamiliar tradition; as if it was an electric version of some string instrument played in some remote culture for hundreds of years.

The treatment intended is chrome hardware (I'd go gold, but the bridge I have my eye on is chrome), sea-green solid-color body (probably not dyed wood, but an opaque lacquer.) The body might also have some detail painting -- foam/bubbles -- on it. The neck in this design might be built around a traditional neck, with a replacement headstock, but the best look would be a pale wood which requires, basically, hand-carving the entire thing out of ash or alder or maybe spruce.

At least the body, being solid-color, can be carved out of joined, non-appearance, and non-matching hardwoods. Meaning I can make use of what is affordable and in town, instead of spending $70 plus on a body blank plus shipment.

How Much Wood Would a Woodworker Work, if a Woodworker Would Work Wood

I'd love to have a shop. Even a garage.

I've been working my way back into building things. I have every intention of following the Pulp Adventure hand cannon, plus the medal clasps, space pilot badge, retro style headphone amp and so forth with new props. I invested in basic casting supplies and re-learned some of the technologies. I taught myself how to leverage AVRs to control servos, lighting, and other effects. I started a basic collection of home tools. It is time to start in on some projects!

I'm particularly interested in trying out the quick-fabrication technique of laminating and shaping MDF and sintra over a simple steel core, to make prop guns and swords. This is a natural task for a scrollsaw, which I have been thinking may be my next power tool acquisition.

I've already been asked to consider a stunt version of the Fury Gun, plus a display stand for the one I already made, and to finish a Lewis Gun kit for that matter (and I have a handful of smoke grenades waiting on the final part).

But I'm also very intrigued at making a musical instrument or two. A solid-body electric guitar (or uke) is about the simplest luthier project possible, outside perhaps of a nearly-finished Saga kit. Trouble is, the mechanical demands (strength, weight, tone projection) pretty much require hardwood. And that means that hand tools and a Dremel would take a very, very long time.

And there's two good reasons not to expand my home power tool collection in that direction. One is cost. The other is that an apartment is simply inadequate for sturdy benches, space to lay out, and even basic dust and noise control.

Small tools (aka, a tool that is undersized for the job) suffer from the same flaw as cheap tools; they take longer and, in the end, cost more.

(A cheap tool may get you through one project before it breaks. Try to do more than one, and by the time you finish replacing blades, handles, and finally the whole thing (with another tool of equivalent cheapness) you could have gone ahead and gotten a decent one. And the decent one would have made the cuts faster, neater, taken less clean-up, had less risk of ruining a workpiece requiring you to start from scratch, and, oh yes, less chance of ruining YOU causing you to at the very least spend a lot of money in the local Emergency Room.)

(It's the "Vime's Law of Boots" all over again, and places like Harbor Freight make a great business selling cardboard soles to those who haven't the capitol to invest in better.)

If I were to stick with smaller hand props and softer materials (aka plastics and softwoods, not hardwoods and stainless steel), I could get by with the kinds of smaller tools I already own. It still isn't as FAST, however, as having a full shop. With a full shop you have space to multi-task; paint is drying in one corner, glue setting up in another, and power tools operating in a third.

With a full shop you also have the ability to work fractally. That takes a word of explanation! If all you have is file, you can cut a shape. You just keep filing until you've removed all the wood that doesn't look like the final shape. If you have some tools but limited space, you can get out and set up a jigsaw to rough in the shape, then finish with the file. That is working fractally. But in that limited space, it isn't always worth the time to set up that other tool, and the other tool may not be capable of hogging that rough cut anyhow. So you still end up doing a lot of tasks start to finish with the same tool.

In a full shop, you can stop in the middle of filing, slap the shape on a table saw to cut off most of the excess in one swoop, carry it to the bandsaw and rough in the cut, carry it to the belt sander to do a quick round-over, chuck it back in the bench vise to finish up with a collection of rasps and files, then plug in a hand sander to clean up.

At each point in the ongoing tasks, you can divide it into zones where one tool is more appropriate, do that sub-task, and immediately shift over to the tool most appropriate for the next sub-task. This makes the work much, much faster.

With jigsaw, scrollsaw, dremel and hand files I would have three fractal levels (overlapping quite a bit) to swiftly shape wood and softer metals of smaller thicknesses. The tools would bog down on the largest cuts necessary to build a rifle-sized prop, but for the sizes under I'd be within the zone of efficiency.

These tools, however, are completely out of their weight class in dealing with the 1 3/4" thick hardwood slabs of a solid-body electric!

Right now my best options seem to be an external shop. I could try to sneak a little time in the scene shop at a place I do a regular gig at. It would be semi under-the-table, however, as their insurance doesn't cover outside workers. A better option just might be TechShop. They have the tools. To get access to them, you need both membership dues, and a safety-and-basic-operations class for each tool/class of tools. Those classes can add up quick, at $60-80 per class. And there is no test-out option.

However. The woodshop SBU at the local tech shop includes not just the band saw, table saw, and radical harm///radial arm saw (which I am very, very familiar with after some twenty years in theater scene shops), but panel saw, scrollsaw, and a couple of other things I wouldn't mind so much paying $65 to get up to speed on.

Of course, the wood lathe is another $65, and the planer-joiner and the router table are another $65, and the former is a great tool for prop-making and the later group are both assets to the luthier.

At least the check-out classes last forever; you can think of them as up-front costs. After that, you can just pay for a one-month membership when you've got a project coming up that needs it. Not as convenient for the kind of crazy schedule theater imposes, or the "work on it for a weekend, put it aside for a bit while you work on something else" style most of us are accustomed to. But if you can't afford the money or space for a 4 x 8 foot shopbot at home...

At the moment my plan seems to be to drop in at TechShop SF and see what it really looks like -- how crowded, how well set-up, how conducive to working on a project I could schedule in there. I'm also going to attempt a task breakdown for the solid-body uke to see if I can sneak the larger hogging into the scene shop on a visit or two, and complete the rest with the tools at home. And while I'm out, refresh my memory of power tools available at the local hardware stores, and check out the stock of hardwoods at McBeath.

And if it works out, get some kinds of tools that will allow me to continue on prop making that will also handle carving up a mock-up to see if my ideas look realistic for a playable instrument that would be worth the cost of building.

The cheapest I can get this thing to happen is still over $200. The fish-tail design I came up with requires custom headstock and with that, and quality hardware, the price increases to at least $300 parts and materials. One way or another, I think I need to add another $200 for tools -- whether that is TechShop membership and class dues, new power tools, or (most likely) a combination of the both.

And seems very much sensible that into that matrix of options I need to throw those combinations of tools and plans that have me building a couple of items I KNOW I'm getting paid for.

I'm (Still) Dreaming of a Uk-U-Le-Le...

So there are a couple of other options for building my own solid-body uke. Like, start with a Grizzly Soprano, ditch the fingerboard, have a new one slotted up at LMI in 14.7" scale length, carve a body from MDF (the purists howl, but listening tests show many people can't hear the difference), and set the bridge back to make the scale length come out. I'd still have a narrow Soprano neck, though. Oh, yes...and carve a shallow slot in the pre-made Grizzly neck for a carbon-fiber reinforcement rod, and otherwise trust my woodworking skills to achieve a proper setup.

Add to this, cheap guitar tuners, a re-purposed guitar bridge of the most basic kind, and either a guitar pickup or a hand-wound one. And, yes, I do find it mildly intriguing to hand-wind a pick-up.

But even though the Grizzly kit is a mere $22, you can get a mahogany neck (with rosewood fingerboard) in CONCERT scale length and width from Mainland Ukuleles for a mere $35. There's not enough space in a traditional uke neck for a full truss rod, but you could still slot it for a carbon-fiber reinforcement rod. Of course it would still be a glue neck, not a bolt-on, (unless you got real clever about the butt.)

But on the gripping hand, Uke Builder's Workshop has a Honduran Mahogany neck blank for $16 (who knows what shipping will come out to with all these things, though!) That could be carved to a custom headstock shape, and set up for bolt-on neck, and of course be set for any style or reinforcement all the way up to double-action truss rod. Or just carved thick enough to take the stress. I'd still need power tools for some of the steps, though -- and I'd really rather not carve a neck without a spoke-shave, too.

Unfortunately, neither Shapeways nor CNC (via Ponoko, Big Blue Saw, or even TechShop) are going to be much help here. Either the parts are large thick hardwood with compound curves, or they can be found cheaper already manufactured by people who get economies of scale in their machine-shop endeavors. Except for perhaps something like a complex shape for a fingerboard, or scroll-work, or laser engraving. Or an acrylic body -- I'd rather not cut that out myself.

Which segues into design. The basic design parameters are that it plays well and feels comfortable. Ergonomics trump all other considerations. Following that is general aesthetics; it should look nice, with clean workmanship and attention to detail. The lowest-ranking element is stylistic. For that there are several directions one could go:

Ukulele-like: an all-wood construction, stained and sealed, with as much as possible ukulele body and headstock shape and even details such as bridge and nut style, headstock angle, fret length, etc.

Minitele: a miniature Telecaster; body shape, headstock (changed enough to avoid attention from the lawyers, of course!) and Fender-style pick guard, pick-up ring, bridge, knobs, jack, and so forth. Done in something typical like candy-apple red gloss.

-Ish: designed towards a striking "look" in some style or other; Steampunk, Futuristic (aka acrylics and built-in lights), Diesel-punk (metal, rivets, toggle switches and tubes), Lantean, organo-tech, etc. These are probably the options that most leverage my existing experience in prop building, metal working, casting, and electronics.

Stylized: the shape of a traditional or pineapple uke, but abstracted and cartooned; a Cubist uke, with sharply slanting headstock, emphasized contours, and so forth.

Like No Instrument We've Encountered Before: done with the kinds of materials and attention to detail of a traditional instrument (acoustic or otherwise) but with contours and details that are unique; like Spock's Vulcan Lyre.

I'm leaning more towards the latter two at the moment. In all cases, of course, the first test would be to carve a mock-up body from cheaper material (like blue foam) and even temporarily mount a neck and nylon bridge on it so I can test the ergonomics thoroughly before committing to the actual build.

As far as all that goes, however, I have a couple other musical instrument projects for a rainy day. A cheap "garklein" style recorder with horrible intonation that needs to be cleaned out and tuned. A fipple-flute based MIDI breath controller -- I have the pressure transducer already and just need to find time to bench test the concept.

And other, more useful semi-musical gadgets. I am looking at possible wacky instruments showing up in the pit for Pirates, and I think Willy Wonka should be a total immersive sound design. And I really have to, one of these days, finish wiring up my dedicated Qlab controller surface, with or without the MIDI-over-USB I finally have the software tools to achieve.

And then there's more ordinary props. Compared to the steps, tool work, cost of materials and hardware, and necessary precision of work for musical instrument (even a solid-body ukulele), something like a laser pistol with "sound and lights" electronics inside is SIMPLE.


I took a little time to look deeper at the idea of making a ukulele. Okay, sure, I have a uke already. A cheap Rogue with friction pegs, veneer top, and horrid intonation. I've been meaning to upgrade to a concert scale anyhow (slightly larger fret and string spacing but the same tuning). But I've also had a certain desire to try an electric instrument.

You can buy an electric uke. Most of them are electric-acoustic which is NOT the same thing. Of the steel strings, there are only a few options and most of the decent ones are expensive. What I want is something with the curves and shiny paint of a Strat or Tele, that plays like a uke, and when someone asks where I got it, I can tell them I made it. Or at least assembled the kit.

So I did some research. I could build a cigar-box uke without too much trouble. One downside to that is would probably be less playable than my Rogue; cheap materials and simple construction often leads to less-than-lovely tolerances, and for musical instruments tolerances matter. The other downside is that there's no point in having a second cheap uke. I want an upgrade.

Once you go steel-string, though, even with a solid-body, the mechanics become much more difficult. It is the same problem I had with the "Fury Gun" I built last year; in that case, it was five pounds of good Krups steel on 30" long barrels and I needed proper machined parts to keep it from falling apart under it's own weight.

And then add the problem of it being, well, a ukulele. I'm not going to be happy with string or fret spacing from an electric guitar (even if the tuning worked out, which it doesn't), or even an electric mandolin (for which you can find fairly inexpensive kits.) This was going to be a uke, dammit. Re-entrant tuning and all (unlike a guitar, the lowest pitched string is in the middle, not on the bottom).

So this means I need bridge, nut, and tuners that can handle steel strings. That's a bit of cost already. There's a company that makes a good bridge for a steel-string uke for about fifty bucks. A set of tuning machines will of course cost 20-40 dollars themselves. And you still need ferrules and so forth.

The tension of those steel strings is too much to trust a glued wood neck to. It needs reinforcement, preferably a double-action truss bar (so it can be adjusted to flatten the curve of the neck to within the close tolerances needed to make a properly set-up instrument). And no-one, of course, makes a uke neck with a truss bar. So that's either hand-carve one from twenty bucks of hardwood, or slot a pre-made neck -- as little as another twenty bucks for the pine neck of a cheap Grizzly kit, or a decent mahogany one for 35 to fifty dollars. Plus the truss rod of course!

And that doesn't necessarily cover the frets, which might require some time with fret wire. I am not a masochist, though; if I have to make my own fingerboard, I'll buy one pre-slotted (and pre-cambered).

A guitar pick-up has the wrong spacing and too many strings. You could hand-wind your own. Or you could get a decent four-string pick-up from Almuse for about fifty bucks. And add another twenty-thirty bucks for the basic electronics, and the cheapest set of parts that makes a decent electric uke comes out to at least two hundred bucks.

A temptation appears at this point; to go the other way and accept the challenge of making the cheapest possible electric uke. Scrap and salvage wood. Threaded steel rod for a truss rod. Actual wires for fret wires. But there are two big problems with this scheme. One is that time and money graph against each other. if you want to do it cheap, it will take longer. Perhaps much, much longer -- when you are talking about things like making your own tuners from scratch. The other is that cheap and substitute materials are too likely to end up with, again, a uke that is nearly unplayable. And more than any other goal, I want a decent instrument I can continue to learn and grow on.

So. As another alternative, could Frankenstein a Grizzly soprano kit ($22) and a Saga electric mandolin kit ($116) and make an instrument. At the end of it, though, you'd have a mandolin bridge -- not a solid-body guitar or uke style -- lousy electronics, and a soprano fretboard. And there's no guarantee you can hack a decent Les Paul teardrop out of the pre-carved mandolin body, or re-purpose the Saga truss rod into a Grizzly neck of an entirely different shape.

So it pretty much looks like you need to go the route of purchasing Moongazer bridges and Almuse pickups and Grover tuning machines from Stew-Mac, rent some shop time to fit a truss rod and carve a body from a nice chunk of hardwood, and spend a few bucks on top of that for epoxy paints and chrome miscellaneous hardware like strap pegs -- oh, yes, and shape a nice pick guard.

So the total cost in parts and tools is very likely to exceed $300. The time commit is not THAT bad, not with pre-slotted fingerboard and carved neck and pre-shaped bone nut and so forth. But all in all does not seem an appropriate project to start at this time.

Tuesday, August 30, 2011

Props where props are due

When I started in this business it was as a scenic carpenter. I don't mean a carpenter that is good to look at (although I remember one nice young lady who interned at the Park...) "Scenic Carpenter" is the general hand of the set-building trade.

As a scenic carpenter you are expected to be familiar with not just wood and standard theatrical construction (the muslin flat, the platform, the basic staircase), but also a fair bit of both house and finish carpentry (hanging doors, building cabinets), but also non-wood materials. As a carp I was also a welder with stick and wire (and a very small amount of gas), sculptor in styrofoam, chicken wire and glue-muslin, a fairly amateur plumber and electrician (for what we call "practical" set furnishings from desk lamps that light to sinks with running water), and a smattering of other materials and skills including laying tile, pouring concrete, threading pipe, casting with resin, running an industrial sewing machine, and so forth.

(Plus there is rigging and the basics of stage machinery...but that's a whole other subject).

Out in a medium-sized shop -- like Boston's Huntington Stage -- the carps are doing the more basic work as well as lifting and carrying, one or two are better welders than the rest and do the brunt of the welding, and one or two will be split off for most of a week on any special projects the Master Carpenter/Shop Foreman doesn't take for her own. Often you'll have one or two people who are better with finish carpentry as well, a handful of interns who are best kept putting legs on platforms, and part of your crew will "float" from building to helping the scenic painter and her team.

The connected field is props building. Most of the work of the Props Mistress (or Props Master) is wrangling, renting, and scouting for the things. Few companies can afford the time to build every lampshade and pocket watch, and there is no sense in building a dozen parasols from scratch when someone in the area has something that will work for purchase or rental (or that can be suitably modified).

Sometimes, though, you have to build it (and far more often, you have to repair it!)

As a props builder in a theater most of your labor will be things like spray-painting washers gold (to make heaps of quick-and-dirty money for a period show). Only every now and then do you have an important, detailed, actor-carried practical prop like Oaklahoma's "The Little Wonder."

In re that specific prop: The description in dialog is that it is basically a simple prism viewer with a folding knife. The dialog says you wait until the victim is holding it at eye level, unfold the knife, then shove his hands down and into his gut. Forget that. I made mine more of a Speed Racer gag; the knife comes out the viewing lens.

Mine was constructed from several pieces of nested pipe, PVC and steel. A rubber dagger was pressed against a spring and held there by a cut-off bolt running through an L-shaped slot. Turn the front ring, the bolt slips out of the "L" and travels to the end of the slot with a satisfying "chunk" of steel against steel; popping the spring-loaded blade six inches out the business end.

Practical props (aka props that have moving parts or other functions) are the most fun and the most difficult and also the least frequent build you'll have. More typical of the things I built was a fake speaker, painted Navy gray and mounted on the set for Mister Roberts. As I recall, the round body was sonotube, the bracket was 3/4" plywood as was the front ring, and the grill was expanded steel over cloth. The decorative bolts were 3/4" nuts roughly filled with hot glue and painted gray like the rest of it.

My proudest "build" was actually a rescue; the "Man of the Year" award broke on stage on Saturday night and I found the original mold in the props shop and pulled an all-nighter casting and painting the replacement to have it on stage for the Sunday matinee.

Since moving over to the Electrics side of the house (which is generally divided into lights and sound, the former being tasked with any electrical stuff that isn't stage machinery like a motorized turn-table, and the latter dealing with only those things that are part of an audio or video chain), I've not been building many props. Among other things, I don't have a scene shop handy anymore.

I have built a couple little things on my own, however. Last year I went on a small but personally expensive spree and bought more power tools than really should be installed in a small studio apartment. I'm still barely on the edge of what I could whip up with a good basic shop. It is amazing how fast you can work when you can shift from bandsaw, chopsaw, bench sander, drill press, etc., as you refine a shape.

I have hopes of doing some more personal props during the year. My last one was a monster; a thirty-pound full-scale replica firearm with moving parts. Talk about prop buildings involving lots of different materials and techniques; it included welding, brazing, hot-bending, plastrut, sculpting, detail painting, metal fabrication, and 3D printing.

But that's the direction I'm going now. I don't have connections to a theater right now that would want me to build big, complicated things for them. Unless they have moving parts or electronics...then it is possible it might happen. So instead I'm doing stuff for fun, for friends, and the sort of stuff used by the cosplay crowd.

Which was part of why I was learning to program the AVR; I wanted to have (and now basically do have) a tiny computer I could stick inside a hand prop that would sequence lights and sounds and motors in any way desired.

My desired project at the moment is some kind of fancy-looking science fiction gun. Not something from any existing movie or TV show, and not of the more common big and heavily weathered look; something that is more small and elegant and highly detailed like a 1930's cigarette lighter or a well-built machine tool.

The most likely next project is going to be making some M18 smoke grenade mock-ups. I'm just waiting on some empty smoke-in-a-can to come my way so I can cut off the lids, replace them with a resin cast lid/fuse adapter, and screw my eBay-purchased fuses into them.

Friday, August 26, 2011


I notice several visitors have been to the posts where I talk about my cheap one-button MIDI devices. I currently make them with Arduino, which is these days pretty much a no-brainer (one resistor, and the MIDI library already packaged in the IDE.) I've been working on doing them both by bit-banging one of the cheap thru-hole AVRs (aka ATtiny45), and by leveraging TeensyUSB or a similar USB-AVR breakout board to send MIDI over USB. There is also a new solution based around the latest crop of Arduino's that makes use of the fact that the Uno uses an AVR (ATMega8U2) instead of the older FTDI chip for USB.

Anyhow. I'd gladly document, or even make an Instructable, on my cheap MIDI solutions if I thought there was sufficient interest. Someone answer this post, and we'll see.

Thursday, August 25, 2011

The Kids Speak Out

It seems strange to hang wireless microphones on kids. But the sad reality is that area mic'ing doesn't give you the volume before feedback, or even more importantly, the intelligibility gained by having a head-worn microphone.

Children's theater is a strange bird. Often as not it is a school program or a church program, and there are very few people on board with experience in technical theater. At the same time, some schools are affluent and some have friends: the gear you will find covers the entire range from two channels of Radio Shack special to 24 channels of top-of-the-line Shure ULX. The only thing that remains the same is that the gear will be stuffed in a closet, often covered with grime, and no-one will know how it works.

One of the toughest hurdles I have to cross is getting people to understand the implications of gentle support. That we need the band to play softly (but enough in monitors to keep the kids on pitch and time!) That the microphones are SUPPOSED to sound like they aren't on. And that the preferred position is NOT taped to the cheek one inch from the mouth.

The default, sadly, is usually to tape mics as close to the mouths as possible, EQ only to control feedback, and leave everything on and loud for the entire show. Once they hear how good it sounds with a properly tuned and adjusted system, though...expect to get hired again. And again.

The kids are a delight. The first day I show up, at least one member of the cast will recognize me from a previous gig and yell, "It's the mic guy! We're getting mics today! Yaaaay!"

Then of course as soon as you get them on mic they'll forget they are wearing it, and touch their faces, adjust their hair, talk just before an entrance, or even try to whisper directions to another actor while on stage. Sometimes they'll forget their entrance entirely and you'll put up their mic only to hear (loud!) dressing room chatter. Oh, but then there are the times between scenes in a stop-and-go rehearsal where it seems half the cast is tapping on their mics with their fingertips and calling, "Is my mic on? I don't think my mic is on!"

Two things save you here. The first is that dressing room chatter, and quick-changes in the wings, are loud. Both have distinctive spiky patterns on the meters. You don't even need to PFL that mic to know it shouldn't be turned on. On-stage singing and even dialog tends to be softer and has a rounder volume contour. With practice, you'll learn to recognize it from the meters alone.

The other is that half your ensemble is marking it. Take a quick stroll through the PFL into a pair of headphones during an ensemble number, and start muting each microphone where all you hear is tentative, breathy, whispers. By the time you've winnowed it down to just the strong singers you've got less than half a dozen mics up -- and much less chance for accident.

It will still sound like a full ensemble. Since we are doing reinforcement here, direct acoustic energy is still coming from the stage. And almost no-one in the audience will ever realize little Bella and Cindy and Evan are singing into dead mics.

The best sound, as with adult actors (particularly women) is with a head position. I go through multiple packs of the cheapest hair clips Wallgreen's stocks; generally tape just below the hairline, hair clips at roughly 2:00 and 10:00 o'clock, and depending on the length of the hair, presence of pony tail, style of costume, a third clip near the base of the pony tail, or tape around the 7th cervical vertebrae (high enough to keep the cord from developing a loop, low enough to catch as little as possible of the fine hairs along the back of the neck), or clipped to the neck of the costume.

Bobby pins work but you have to take the time to reverse them (aka use more than one, pointing in opposite directions). Toupee clips need to be prepped ahead of time because most of them will not close over the thickness of a mic cable.

However, children's theater tends towards costume dramas and shows about animals (Seussical, Narnia, Jungle Book, Aristocats, etc., etc.) All the things going on and off heads makes the ear position necessary.

Let me stop and point out here that although it is tempting to tape to ear/along cheek to achieve that last couple of possible dB from a quiet-voiced actor, what you will end up with in most cases is merely a louder breathy, indistinct mumble. The sound has to start with the actor. In borderline cases bringing the microphone closer (better to use a true "Madonna-Mic" like a Countryman E6) is a worthwhile trade-off, but apply this on a case-by-case basis; not as a default solution.

I can not emphasize how important it is to demonstrate the ear position to your assistants, and to check on them frequently. They will inevitably migrate. You want the microphone to follow the cheek bone (generally right below it). This means it effectively points towards the philtrum, not the mouth -- but this is where it is supposed to go. When you don't keep an eye on the taping, they'll end up being angled down and have the element right on top of the drum membrane surface of the cheek. NOT a good sound.

For adult actors I'll tape as close to sideburn as possible. For kids, it depends mostly on the costume. A good default is the "point" of the cheekbone. Put the element there, put the tape behind the head of the element (not over it). Yes; again, some people don't understand the physics. They see the hole in the front of the mic (the grill) and think that's where the sound goes. They don't understand that the entire head is an acoustic device and you change the character of the sound by putting tape over it.

Many kids have thick enough hair that you can spare them the uncomfortable tape behind the ear and hairclip to the hair tucked behind their ear instead. When you do have to tape, try not to catch any hair, and if the skin is oily, wipe down with an alcohol prep pad first. For the smaller kids, tearing the tape down the middle to make a narrower strip also helps.

And a non-technical note on this. It isn't smart, not these days, to get backed into attaching all the mics yourself in some dark corner of the theater. Get several people involved, get the parent volunteers, stage manager, director -- people who have been properly vetted and fingerprinted. I've never seen it happen, but all it takes is one parent mis-hearing what their kid said and you will have a very short career in children's theater.

As with any actor, or any musician, be respectful, make sure they understand what you are doing before you start sticking tape on their faces or fiddling with their hair, and answer questions. Tell them why a microphone has to be in a certain place, tell them how it makes them sound better. Get them to understand a little of how the microphone works, and they will work for you in making sure it is set up right and it stays right through the performance.

Treat them like professionals.

A last couple of tricks. Almost everyone uses those over-the-door shoe bags to hold the prepped transmitters. When you arrive for the show, put in fresh batteries, condom the mics, check to see that the connector is secure, the clip light isn't flashing in a way to indicate a broken element, the fuel gauge shows a fully charged battery. Wrap it loosely and stick it in the shoe bag under the actor's name (or character name; whichever is most convenient and informative).

When the mics come off again, be profligate with the alcohol pads. They don't loosen tape any, but they do numb the skin slightly. Be gentle in getting the tape back off. If the tape is really stubborn (and painful!) use a little goo-gone on a rag first. Pull batteries, bags, condoms, moleskin et al and set the mics back in the shoe bag to air out. Hang the bags to dry outside.

Many children's productions will be double-cast. It is unfair for a class production to have one person get a starring role and everyone else has to play spear-bearers. As partial answer to that, most programs will have an "A" and a "B" cast alternating performances.

Since often these are drawn from the same pool of performers, you can simplify your life a little by assigning microphones by actor instead of character. Then when the "B" cast comes on you re-patch the channels and re-assign the EQ and other processing. On a digital board like the Yamaha LS9 this is literally a matter of a single button press; change the soft patch and call up the new EQ et al just by loading the appropriate show.

Monday, August 15, 2011

Is this thing on?

Finished up the current musical while trying to recover from a bout with the flu. Sunday was two performances, then strike. An hour after leaving the building I was asleep. Woke up at midnight, ravenous. Ate, went back to bed and slept till noon.

So now I'm shopping for wireless microphones. Finally decided it makes the most sense to own a few channels of my own, and rent them to those (few) clients that are willing to pay a few bucks for gear. Browsing eBay over coffee, with the widest possible search parameters so I can pick up those gems that got mis-catted and thus missed by everyone else.

I'm pretty much determined to put together a rack of 4 to 6 Sennheiser G3's. I've been using that model quite a bit of late and I have been very happy with their performance. But I'm keeping my eyes open. I am too "Shure? Unsure!" to want any more SLX's that aren't for a really, really good price. And I know ULX's are out of my price range at the moment, and most of the UC's are in the dreaded 700 band. Plus of course I know better than to get anything with the name "Nady" on it.

I've got one eye open for antenna distros. Although I shouldn't need one for my Sennies, I have wished for a while I could talk one of my clients into hanging one on their small collection of SLX's. The built-in quarter-waves barely punch a signal from stage to wing! But this is the company that will only grudgingly pay rent on some much-needed channels -- talking them into almost a thousand bucks of directional antenna and antenna distribution is not really on.

I'm going to be pushing pretty hard at the short-lived surplus from cashing out my IRA to do this much. Down the road will be getting B3's for all my mics, plus purchasing one or two snap-on transmitters so I can offer hand-held as an option as well. And...if it turns out I'm not getting a clean signal in the venues I work...antenna distro for them, too.

Oud Laptop finished the show with flying colors. At this point I'm leery of cracking the case again to experiment with the ATA connector. Well...there's a children's musical in the same building, so I'll wait until that is over before I take the laptop home.

Meanwhile my rebuilt gighertz titanium has lost picture. I think I got some oil from a Chinese take-out in it when the latter got loose in my gig bag. So on the schedule for this week is to strip it down again, clean it, test the fans are still running, clean the connectors -- and prepare to install a new display inverter perhaps. I'm hoping it isn't VRAM at fault, which I believe is soldered on the MOBO. Or worse yet, the LCD itself -- you can get them surplus, but they are a huge, huge pain to replace.

Tuesday, August 9, 2011

I owe, I owe, yet off to work I go

I am signed on to three different musicals. One is ongoing, with the last of 34 performances happening this weekend. Immediately following I load in a one-weekend show that opens, well, that very Friday. Then on the closing night of that show I race off to another town for a sitzprobe and a recording session, from there to one week until tech and two weeks until opening. Fortunately, I'm not running the board for that last; because I hop on a plane for my first vacation out of the country in almost two years.

With six or more performances a weekend, my time off is roughly a three-day weekend. Minus the time spent in doing repairs and maintenance on the ongoing show. Minus, last "weekend," assisting to set up yet another musical (that I am fortunately neither designer nor operator on) and the "weekend" previous to that, loading in, teching, and running board for a children's musical.

You'd think I'd at least be picking up a bit of money. Not quite. The fee for any of these shows is a bit over a thousand dollars. Which sounds like a nice lump sum, but consider; broken out over four hours per performance (with set-up and clean-up) it already works out to barely over ten bucks an hour. Add the hours of tech week (rarely is a tech week a shorter commitment than 40 hours) and time at home in the studio preparing effects, and you are talking not much over seven bucks an hour.

Add to that; even though the show is MOSTLY evenings and weekends, with call times as early as 4:00 PM in the afternoon for prep and repairs, and the fact that you didn't even leave the building until ten or eleven the previous night, it is very hard to schedule another job. Particularly because my field is, well, theater; the other jobs calling me ALSO want me on evenings and weekends. And even places like UPS or McDonald's are not going to be really happy about having someone cancel shifts without notice because something broke at the theater and they have to go there to repair it instead of working their scheduled shift.

So you are basically restricted to working shows serially. With a four or five week run, plus one or two weeks of necessary technical rehearsal, designer's runs, rehearsals and studio time and meetings, you basically can get two shows in three months (if you are actually running the board. If all you are doing is designing, the block of time you have to free up is rather smaller, AND you have a lot more flexibility in when you schedule the work you have to do). At 1,200 to 1,400 for a design-and-run, this breaks down to under a thousand a month income from the theater work.

And that's before expenses. Such as all the technical gear, including powered monitors, microphones, cable, DI's, and so forth I typically provide without charge.

So want to run board for your own shows at a midsize (sub-regional) theater level? Be prepared to live frugally.