scottsdale

1978 - 1988

I was

Audio Technician for the City of Scottsdale at the Scottsdale Center for the Arts.

Inside this building is a 700-800 seat theatre with a steep rake and interesting acoustics. There are large hard torms house left and house right with large walls following them. The ceiling above the theatre is "infinite"; mostly absorbative. With a RT time around 2 seconds, this hall is used for many solo, ensamble and symphony performances.

Don't know why, but I'd like to digress to something silly, different and interesting - for some reason, this picture reminds of the "Assisted Resonance" electronic acoustic enhancement system installed in the theatre. At a cost of almost $100,000 in 1975, this British "invention" manufactured by A.I.R.O. (Acoustic Investigation Research Organization) consists of 72 channels each of :

Microphones encased in Helmholtz Resonators. These are machined tubes of various sizes, for each frequency. Interestingly, the higher frequency mics are ceramic, and the lower frequency mics are dynamic.
Electronics including steep filters, gain adjustments and a 50 watt amplifier. There are 12 power supplies; each feeding 6 amplifiers plus and minus DC voltages.
Loudspeakers (all Celestion 12" woofers) mounted on a large open plywood frame - a quasi-true "infinite baffle".

This system works exclusively below 1000 Hz and goes down to around 60 Hz. The budget was trimmed, when it was installed and the first octave was left out. I believe its intented use is to boost the low-frequency reverberation time response of the room from approx 1.6~2.3 seconds to 2.6~3.2 seconds. This is done by combining the input and output of all 72 channels in-polarity and harmoniously.

Although the Scottsdale Center for the Arts was a beautiful architechtural statement for it's time by Bennie Gonzales, there are acoustic flaws in the theatre which could be improved upon greatly.

Last time I checked, in October of 2001, the AR system was not being used, it was in disrepair; a relic from days gone by. But hey, it is still sitting there!

Oh well, those were the days.

The room also has a Bozak quad speaker system with each of the four channels having its own subwoofer; at the time, we had a 28 channel "Tangent" console, with a custom output module of 8 bussed quad pan-pots!

Sniff....

get back to where you once belonged!