By Danny Maland
- So as not not tip my hand too early, I’m going to leave “Grandpa Maland’s Small Town Wisdom” for a bit later. You see, this post is meant more for the younger pups in the shop, and involves a short quiz that may be administered by one or several of the more seasoned pups.
- (We’re all pups in the end. Some of us just have more years/ miles/ hard knocks on us.)
- Here’s that quiz:
- Question 1 - What is the worst kind of problem that can arise during the installation or operation of an audio and/ or video system?
- I certainly can recognize that a number of answers might be considered to be completely valid, but I’m going to opine that the most correct answer is this one:
- The worst kind of problem that can afflict an audio and/ or video system is an intermittent, show-stopping problem.
- The key word up there is “intermittent.” Why?
- Let’s first consider a relatively minor issue — say, an audible-but-not-loud (maybe 40 dB or so below the continuous level of “nominal” program material) buzz or hum stemming from a ground loop. If that issue is “steady-state,” then there are two things working in favor of a person working on the system. The first favorable condition is that the system, having predictable behavior, can be meaningfully and scientifically troubleshot. The original system configuration and steady-state problem act as a sort of control, and changes made to the system during troubleshooting are the variables. Consistent system behavior means that potential causes for the ground-loop can be investigated and eliminated until the actual cause is found and remedied. The second favorable condition is that a not-overbearing steady-state issue has a real chance of eventually being “filtered” by the brain of a person who is listening to the system. It becomes like any other kind of continuous noise or distraction, in that is taken as a “given,” recognized as not being part of the program material, and then ignored after a few minutes. This is rather like the hiss and other sonic imperfections that people would hear while playing a vinyl record. (Somebody out there remembers what those are, right?)
- Of course, our ground-loop problem isn’t made acceptable by the ability of the listener to ignore it. It’s just that it’s actually tolerable until it can be fixed.
- Now — what if that buzz comes and goes? First, troubleshooting becomes very hard. The system now has unpredictable behavior, and so it becomes difficult to ascertain whether any given change to the system has actually had an effect on the problem or not. The system’s original configuration and problem can no longer be considered “controls” in the troubleshooting experiment. Instead, the problem enters into the list of variables...and this can make it impossible to actually isolate in more severe cases. The second annoyance is that the intermittent buzz is now much harder for a listener to ignore. When it is gone for a while, and then unpredictably appears, the listener’s brain is very likely to latch on to it as a disturbance to the program material. The listener’s experience is jarred by a signal that, by being intermittent, indicates that something is going wrong and they need to pay attention to that something going wrong.
- Obviously, a ground-loop buzz or hum isn’t a fatal error. However, extrapolating this up to a “show-stopper bug” is just a matter of upping the stakes.
- Consider a show being mixed on a digital console. The stage crew has just finished changing over the stage from “Bobby’s Boomers” to “Camille’s Crooners,” so the console operator recalls the scene written for the band during sound check. The console loads the scene-
- And something goes horrifically wrong.
- The console’s control surface locks up. The audio engine stops with a bang. The operator asks the stage crew to shut off the power to the PA system’s amplifiers, and reboots the console. Being a savvy sort, the operator then tries to reproduce the problem. The operator again attempts to load the scene for the new band, and again, the console throws a fit.
- This is troublesome, of course, but not unpredictable. After a quick conference with the band and crew, everybody decides to just wing it. A basic mix is thrown together, and the show goes on. The operator doesn’t load the offending scene, and the console happily works as it should.
- Contrast this situation with one where the console also stops with a bang upon a scene recall, but then recalls the scene without a hitch upon reboot. Then, 30 minutes later, the console throws a fit during a fader move. Reboot. The console is then happy for two hours, after which it spontaneously reboots when the operator selects the EQ page for channel 14.
- This problem is also a show-stopper, but it’s far worse than the first scenario. Being that the issue is intermittent and unpredictable, there’s no way to nail it down. Could the power supply be failing? Could there be a problem between firmware version 24.18.a.12.99 and this one particular configuration? Could an option card be working loose? Could it be... Could it be...
Further, every second with the console is a nail-biter. When is it going to go down again? Will it reboot each time? How many more nasty looks will the event coordinator throw at the mix position?
In the end, a problem’s severity is only one aspect of how bad the problem really is. A severe problem that occurs at random is far worse than a severe problem that occurs under predictable conditions.
I can imagine Grandpa Maland right now, leaning on his fence, and complaining about a troublesome horse: “I wish that son of a gun would just go lame and stay that way. Then I might be able to figure out what’s wrong with ‘im.”
