Re: Q: Conseils pour installation sonore - Advice for sound installation


Subject: Re: Q: Conseils pour installation sonore - Advice for sound installation
From: Dennis Bathory-Kitsz (bathory@maltedmedia.com)
Date: Mon Feb 22 1999 - 11:23:43 EST


At 16 46 02 22 1999 +0100, Roald Baudoux wrote:
>In order to set up a sound installation in a half-permanent manner, I am
>looking for advice about the gear to use. It is about autiomatically
>spacializing sound originating from a multitrack device with a number of
>loudspeakers corresponding to the number of tracks (between 16 and 32).
>This would last three months and would be set outside, in a place
>without roof, exposed to rain. But, as this would be in summer, there is
>no risk of coldness.
>
>What kind of playing device would you recommand (Adat, hard disk, DVD,
>Dolby Drive, sampler...), as this would have to run for long times
>without interruptions? However, these players and the amplifiers would
>be in a protected place, inside.
>Do you know loudspeakers made for outside installations having an
>acceptable sound quality?
>What cables or protections to use?
>How to face possible vandalism in an open place?
>What are the pitfalls to avoid?

I faced this problem in a 1991 outdoor installation powered by
windmill-generated electricity. It was tricky.

Here's what I used, what worked, and what didn't:
1. Since it was outside but protected, I used endless-loop cassettes
connected to a computer interface card, plus algorithmic computer-generated
sound (static RAM, battery backup, self-booting, no hard drive), with the
equipment stored under sealed seats in one of several small structures. I
figured the fidelity would be lowered anyway by the location, so the noise
from cassettes wouldn't be an issue. It wasn't. And the cassettes survived
fine, at least for 10 days (see below).
2. I built the above-ground speaker systems using fully sealed boxes,
high-quality, 4-inch, polypro-cone speakers, and everything sprayed with
several layers of a weatherproof coating. These worked fine, although the
speaker cones facing the sun bleached out. For areas where highest fidelity
wasn't important (sound coming from the ground, in this case) I used
ordinary outdoor plastic PA speakers.
3. I used heavy buried power cables for the long run to the speakers, but
you say yours a 'semi-permanent' installation. You might choose proper
outdoor cables inside PVC tube if 'semi-permanent' means several years.
4. Vandalism was the biggest problem. After 10 days, vandals destroyed or
stole all the small sculptures, ripped out the seats and stole the
computers and sound equipment, and damaged the windmill. They left the all
the speakers, though, which still work to this day. But the installation
was essentially useless after that -- see
http://maltedmedia.com/people/bathory/wolf5/ for pix of the installation.
5. Other pitfalls definitely included:
...The question of power and safety. Our system was entirely low voltage
(15 volts), which we decided to use after we discovered the insurance for a
110V-powered system would be prohibitively expensive, and isolating users
from potential shocks would be very difficult.
...The quality and volume of sound. I underestimated the output level
needed outdoors and undersize the amplifiers. Admittedly, this bordered on
an Interstate highway (in Vermont, not too loud), but it still required
higher sound levels than I expected.
...The quality of the connection points. The weather quickly affected the
solder connections on the speakers, so I replaced them with sealed screw
terminals.

Hope that's a little helpful.

Dennis
http://maltedmedia.com/



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