« My Personal Project List | Main | Would The Real Santa Clause Please Stand Up? »

My Life As A Sound Tech...

December 19, 2006

Among the many things I do here at the church, part of my job description is sound and media. I'm specifically in charge of making sure the sound system works properly and sounds great. This being the Christmas season, it was time to prepare the sound system for the upcoming Christmas program on Christmas Eve.

We did a complete overhaul of the sound booth a couple years ago and in the process I moved all of the lapel microphones from the front of the stage to the sound booth in the back. Unfortunately this worked perfectly with an empty room, but once bodies filled the auditorium the signal would cut out on all the lapel mics. This became a problem that I didn’t really want to fix anytime soon. The Christmas program has four different speaking parts requiring the use of our lapel system, so I was forced to fix the problem.

I spent all day yesterday moving microphones, power supplies, and CD players into different racks in order to make everything work. I got all the lapel microphones and the power supplies in one rack and put it on stage and then I put all of the handheld wireless mics and the cd and tape deck in the other rack that stays in the booth. Turned it all on, tested the mics and in the process I suddenly noticed an old friend. The buzz of DEATH!

For years and years we had this nasty buzz in the system. If you have the stage lights turned all the way up the buzz gets quiet, but if you dim the stage lights at all the buzz gets super, super loud. If you plug the computer into the sound system at all then the buzz becomes unbearable. This was a problem that went away when we did the sound booth because I moved all the microphones to the back. We originally thought it had something to do with the dimmer switches in the back so we changed those out during the booth construction and just figured that was the problem in the first place. Guess what, it wasn't the problem at all.

I knew the buzz was coming from the microphone rack that I Just moved up front, but I couldn't figure out why. So I went up there and unplugged the whole rack from the power source and the buzz disappeared. I thought this was strange. I unplugged all of the microphones from the rack mountable power supply and plugged just the power supply in with no mics attached to it and the buzz was back! The rack mountable power supply that is "specifically" designed to keep electrical noise out of the system is the thing that has been creating the buzz since we put it in 5 or 6 years ago. I plugged the mics into a normal, cheapo 6 plug power strip and the buzz was no more.

I am now thinking back to all of the stuff we did in order to try and eliminate that buzz. We bought buzz eliminator boxes, we changed out the dimmer switches, we restrung a lot of wires, we changed circuits, and we moved all kinds of stuff to try and figure out what was causing this and come to find out it was just the rack mounted power supply failing which created some wicked electrical loop in the system. The strange thing is all the different systems it affected. We thought it was the computer at first because the buzz was louder when the computer was in the loop. Then we thought it was the lights because the buzz would increase and decrease with the dimmer switches. Then we thought it was the projectors because the buzz created some interference causing a line to go down the screen. Then we thought it was the electronic keyboard because the buzz would practically go almost silent when you unplugged the keyboard from the sound system. Then we thought it was the circuit the stage was hooked to in the electrical system. Then we thought it was the piano mic picking up interference. Now I see that these were all simply symptoms of things that were affected by the faulty power supply.

As of right now everything works. The Sullivan High School Show Choir is doing a program here at the church during lunch for B.A.L.L. Club (a program for senior adults). I'll get to test everything out during their performance to see if it all works. The ultimate test will be on Thursday night during the dress rehearsal for the Christmas Eve program.

Comments

Posted by: Michael Morgan
December 19, 2006 05:12 PM

Thanks for all the hard work. It will make my job easier during the cantata.

Posted by: Christopher
December 19, 2006 11:44 PM

Whoo hoo! I hope that works so you don't have to move that stuff around anymore.