The Art & Science of Audio & Video

The Service Call That Didn’t Need Any Service!

Many of are accustomed to dealing with clients that do not have dedicated audio/video people on staff. I’m sure you have received a call from an upset customer that is convinced your system in malfunctioning and causing them embarrassment and headaches. More often than not these items can be resolved with a little TLC.

Once of the most difficult hurdles to overcome is knowing you are about to walk into a potentially volatile situation with emotions and possible tempers flaring. No matter what you must still walk in with you head held high, confidently introduce yourself and address that you are hear to take care of any problems the customer may have. Many times you know the description of the problem given to you on the phone just isn’t possible and it could be for any number of reasons. Some claims are so extreme they contradict the fundamental principals of physics so you know going in that science is on your side and that you simply need to determining where the system has spun off course.

This is somewhat of a side note but very important to our topic of conversation. With the vast use of DSP being applied in even the smallest of systems we have eliminated a huge source of potential problems where parameters were easily tampered with on original analog equipment.

My recent experience with this was in a church with a considerable investment in two Intellivox line arrays . You’ll learn quickly how this tends to directly effect the volatility of the situation! The claim was that the speakers were failing and completely unintelligible. Knowing that unless there had been a catastrophic failure it is highly unlikely that the problem lies with the speakers. To satisfy my own curiosity I played a CD and walk the entire floor of the sanctuary listened for any acoustical anomalies that could be interpreted as problematic (i.e. lack of even coverage, comb-filtering, early reflections, etc.). Everything seemed to be perfect as far as I could tell. The client was adamant that there is a problem and here was the defining clue “parishioners are constantly complaining that they can not understand the Fathers and Deacon”. Automatically I begin to suspect that the problem is isolated to the wireless mics that the clergy are so dependent on. First thing I do is check that each unit has fresh batteries and that the antennas are in and accessible place for optimum reception.

At this point I approach the board accompanied by a gentlemen that volunteers his time to run sound, as often as he is available. One complaint was that the voices sound like they are in a “can”. Looking at the console I observed that all of the high pass filters were in engaged at 80hz. The Low Frequency was cut about -12dB on every mic channel and there was a 6-9db boost at about 600hz on each mic channel as well. With this in mind bringing the faders up I would have fully expected to hear exactly what the customer was explaining, a very hollow and nasally sounding vocal. So I flattened out all of the EQs for a fresh start. Side note here this is a Mackie SR24 console we’re working with so not a lot of feedback LEDs etc. I finally asked the father to begin reading into his mic, I had good level, that’s a good sign but upon raising the fader I had nothing. At this time I notice this channel was not assigned to the main L/R mix. So my eyes scanned down the line of the other 23 channels only to discover that every channel that had a wireless mic handheld or belt-pack was not assigned to the main mix. So for all this time what they’ve been hearing is the off axis residual from the overhead choir mics, podium and ambo.

The moral of the story is this, it’s amazing how fast the tables can turn. I walked into a situation where the client was very unhappy and was completely convinced that they had spent a lot of money on a system that didn’t work. This whole episode played out in no more than ten minutes. Not to mention this location was an hour drive both ways to perform a service call that……..didn’t need service!


July 14, 2008 - Posted by | Troubleshooting | , , , , ,

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