Trouble Shoot

Over the last few days we've been very busy.
We had contractors in house re-locating seventeen Soundweb boxes (which means new wires and about 1500 connections), we've been re-configuring things in the control room to accommodate the new PM5D, the construction projects are winding down, there were several events and internal meetings in the building, and we're trying to get ready for the impending football season. We've also had our share of problems.

One of the things that any audio guy needs to know is how to troubleshoot a problem. If you think the sound should come out and it's not, you gotta figure out why. Sometimes you have time to figure that out but it can just as easily happen during the show when the producer or director is shouting something about your overall IQ and family history. You have to have troubleshooting chops to be a good sound guy.

The first step to figure out why your gear isn't doing what you want is figuring out what you know. While that sounds pretty easy, it can often be the hardest part of fixing your problem. It's all too easy to make assumptions based on past experience and those assumptions can lead you on false paths. You know that mic works because you just used it yesterday, right? Prove it. If you can't prove something you think you know, you don't really know it.

You have to think of the system you're checking in terms of signal flow. The sound comes out of some device like a mic or a CD player, travels through some wires and probably some other devices, and then ends in a recorder or falls out of some speakers. You've got to know where you can check the signal or at least see it on a meter. If you can chop the signal path into smaller pieces, it's easier to figure out where the trouble is. You can put the mic cable into a headphone amp, cue the bus you think you're sending the signal out of the mixer on, or see the signal light on the amps for example.
The best approach when troubleshooting is to simplify. The venerable KISS principle is your friend when you're trying to prove that stuff is or isn't working like it should. Are there devices or connections you can remove from the signal chain? Simple circuits have fewer possible points of failure, plain and simple.
I know I said that you really can't assume anything works but you've been around a while and you know that some stuff breaks more often than other stuff. You're probably going to start off by replacing that mic cable, for instance. That's probably a good move since we know that it's more likely to be the problem than the sm57 it's attached to. So you're going to make some assumptions based on your experience but keep in the back of your mind that your A2 might just have dropped that 57 off the golf cart last week... you never know, right?
One assumption I generally make is that it's my fault. I usually think about what I did last. What did I touch? Did I wiggle a cable by accident? Did I hook it up right? Is the selected channel the one I *think* I'm working on? :) (digital mixing update: I EQed the heck out of the wrong channel this weekend wondering all the while why it wasn't doing anything much to fix my slight ring...). In this assumption, I'm right pretty often.
One of the few things I remember from my high school auto shop class is never to assume that something works just because it's new. I've seen new cables with shorts, new power supplies that don't work, new microphones that sound like poo, etc. Always treat new stuff just like anything else. It's junk until you see/hear it working.
What I'm trying to say is that it's OK to make assumptions as long as you know that they are just that, you realize that you might need to go back and prove them out, and you have good reason for them.

You need a few tools to troubleshoot audio issues. Here is a by no means complete list of things that make finding out what's wrong just a bit easier:
A pair of headphones and a decent headphone amp make it much easier to unhook a cable to check for audio.
The Whirlwind Qbox is pretty great for this type of work. It's not great for critical listening but the tone generator and integrated speaker make this box a must for almost any audio job.
A tone/pink noise generator if good to have.
an ipod is good to have as a sound source. It's a good idea to have some speech program (podcast or audio book) loaded into the ipod so you can have somebody talking for a while without making your A2 really grumpy.
You really need a bag of adapters so you can change XLR sex, go to bare wires or well, whatever.
A multi-meter, of course
A known-good mic is a nice thing to have with you. A condenser mic is decent addition too. It's good to know if you can actually provide phantom power.
Some basic hand tools are necessary. You know, wire strippers, screwdrivers, knife, soldering iron with some clamps for holding wires, that kinda stuff.

So keep it simple, know what you know, understand your signal flow, and take a minute (even in the heat of battle) to *think* about what's going on and make a plan to fix it. I've never once found that taking a minute to breath a couple times and think through the situation was a waste of time.

Good luck.