School hall sound system

This one has to be used for every thing from Head of year assemblies to big musical theatre productions and Rock extravaganzas

over the past few weeks I have been extremely busy installing the sound system that I designed over the school summer break .

The brief for the system called for a system with a fair bit more  flexibility, compared to a standard school hall sound system , mainly driven by the “musical theatre and Rock band caveat” requiring:-

• Low system background noise
• Outstanding   intelligibility for the vocals
• A wide frequency response
• A really powerful dynamic range

The system started to look like a major arena system, but in miniature.

Looking at the requirements from the signal source out 

Starting out

• We needed some good sounding robust microphones , sturdy  microphone stands and durable microphone cables.
• For assemblies and presentations we need some lapel /headset radio microphones.

The school had a n Allen and Heath GL3000 desk with plenty of channels a multicore so I did not need to do anything there except check it our and patch it up sensibly.

signal processing

• The next thing in the chain I needed, was some signal processing, to provide an additional 2 way split  (the self powered  mid top cabinets have their own crossover between mid and top) , equalization and dynamic control.

On to the speakers.

• The hall is a standard  late 1950 design; with  one wall and the ceiling faced in hard plaster, a polished hard wood floor, the other wall made from glass panels.  The small saving grace for the hall is about 50% the back wall is faced in a perforated fiberboard sound absorbing tiles, which help a bit with slap back echos. These unfortunately had been pained over numerous times and the other 50% of the wall is covered by  a large mural painted on MDF ,both of which detracted from the attenuation of unwanted echo. To give you a feel of what the acoustics of the room are like , if you listen to some one who is not facing you it is very hard to understand them.
• The key factor to the performance of the speakers is to control where the sound goes, to provide a uniform coverage in the audience with a sharp drop off of level at the rear wall and also minimize how much hits the walls and ceiling  and

“Keep tuned for the solution”