Redundancy

I believe in back-ups. I believe in redundancy. I used to say about parachuting, that you carried a reserve 'chute for when your main failed -- not "if."




I had a little recording session recently. My original plan was to do what I usually do; record on to the hard disk of my laptop via a firewire interphase, and carry a minidisc recorder as back-up.

At the last minute the venue changed; they would be on the main stage. So my modified plan was to run through the sound board into the firewire etc., and use the ability of the sound board to record an mp3 onto a flash drive as back-up.

But they looked like they were already starting when I arrived. So I quickly stuck a new battery in the minidisc and double-stick-taped it to a mic stand and turned it on. Then instead of mucking with the sound board I just pulled a power cable and set up laptop and firewire right on stage near the talent.

Unfortunately, my usual laptop had suffered a magic smoke leak earlier in the week. I'd loaded the drivers on to a borrowed replacement, but now that I needed it, it wouldn't recognize the firewire interface.

So back to Plan B. Grab the mic leads, run them over to the stage snake, turn on the house board, slap a USB thumb drive in the slot and assign the channels to record. Clean signal, the chip is recording, all looks good. The talent is ready to start and I give them the thumb's up. Made it with seconds to spare!

Over the next five or ten minutes I pack up the extraneous gear on stage, haul the laptop back to the sound board, and jigger up an adapter to make it echo what the USB drive is doing (but at higher audio quality).

The session ends. I pop the thumb drive......and it is blank!

So #1, the 48 kHz recording to hard drive, is missing the first ten minutes. #2, the mp3 recording, is completely blank.

But #3, the third recording, my little minidisc recorder, is still humming away where I placed it at the start of the session. And the quality is acceptable.



Once again, having not just ONE backup, but TWO backups saved the day.



One of the tricks to this is that each backup should be as independent as possible. In fighter airplanes, they will have two sets of control runs and one will be electrical and one hydraulic. In Army demolitions they'd have one electric firing chain and one chemical (aka time fuse).

The worst mistake you can make is to create a pinch point. I once saw a bit of rigging where the chain that backed up the terminal connections was attached to the same hardpoint as the rest. That's not a backup; that's just more stuff to fall "when" the hardpoint fails.

In my system above, there was no mic splitter. Whether the firewire or the sound board was first in the chain, if that item failed both recorders failed. However, sound boards are robust. It is much more likely to have the microphone fail, or the recorder fail. So hanging a backup microphone or using a backup recorder makes sense -- duplicating the board, not so much. Still, having the secondary backup as a completely independent system (the minidisc had its own mic, its own wire, even its own power supply) is a good thing.



When you are running sound effects off a computer it pays to have a backup. The easiest backup is to have to key cues on CD. The downside here is that you are going to miss a cue or two as you switch over.

Some people run two complete computers, kept in synchronization. So far I haven't seen anyone automate the switch-over, but the theory is that if anything in the chain fails you throw a couple of switches and everything from computer through audio interface is swapped out.

And in any case you have an entire working copy saved in a media that allows it to be loaded on to a replacement computer. Qlab is very nice for this; it will create a complete self-contained show backup with the "Bundle" command.

In the cast of wireless mics, professional shows (well, any show that can afford it) will stick two microphones on the leads. One pack is the primary, the other is switched to if there is any problem. It is however often difficult to find enough working packs and gaps in the RF band to fit that backup in!




Even in your basic band on stage, it helps to have another microphone or two you can quickly move into place. This leads to several of my basic rules of stringing cable to an onstage band:

1) Always designate a spare snake channel.
2) If there is a cable run that is hard to get to, always include at least one spare cable in it.
3) Set up a spare mic prepped and on a stand so the entire thing can be run out to the band by your A2 (assuming you have one!)

Of course there are a couple related basics:

1) Don't tape down until you've checked for signal.
2) Don't dress out all slack; leave slack at the business end. If you tape it down, you WILL end up having to move it.
3) Label. Things get moved and unplugged.



And that's all I have time for this morning.

I've been promising some more technically detailed posts. I have a few pages of stage plots and mic plots and so forth to scan at some point. I don't know what the audience is at this blog yet, though. I see some fairly technical questions ending up here via Google searches, but I have no idea if this is a place where they might get the help they are looking for.

I need a bit of feedback (the good kind, not the audio kind!) I'd like to know where I should be taking this in the future.