Anatomy Of A Service Call: Even Simple Sound Systems Aren’t Plug & Play Analysis

Anatomy Of A Service Call: Even Simple Sound Systems Aren’t Plug & Play Analysis
Adam Gray

This article basically breaks down the complete going on of what should be an easy service call. It is a church with two wireless lapel mics and all the problems you would expect in a system of a small chapel  distortion feedback etc.  This guy works with 2 cases case A and Case B. Case A is a case full of simple hand tools volt-ohmmeter, impedance meter, and minirator. Basically things that don't require a recharge. And well you guessed it in case b contains items which will require a battery. Since there could be many problems with this system he decided to start at the inputs and work to the output fixing as he went along. First he test to see if the mic are balanced or unbalanced. He hears 3 contact pionts and knows it has balanced potential. After a listen he finds out it is only making sinal through the tip. He then test the T R and S and finds it is the ring to sleeve connector. Overall the mics sounded good through a passive system and he ruled them out. First of all the amp rack was not sufficient for the application, the one input had 2 mics y'd into it and not enough output power to drive the aux. Since there is not a provision to driving a high impedance loudspeaker system but he goes with a transformer to achieve this. Even though he noticed a few things about the amps such as the input lables "LOW-Z". Over all it seems that the problem here was the receiver outputs were too hot for mic input level. This was not going to be a simple fix either. It has turned into a made to order transformer system .