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Joined: Jan 2005
Posts: 15,360 Likes: 12
Moderator-Vertical, Vodavi, 1A2, Outside Wire
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Moderator-Vertical, Vodavi, 1A2, Outside Wire
Joined: Jan 2005
Posts: 15,360 Likes: 12 |
We have been approached to quote a very large PA system for a government building. Although it sounds a bit excessive, they have indicated that we'll need to furnish 150 speakers on each of six floors (900 total). We'll propose a 70 volt system with a separate amplifier (or more) per floor. A single zone controller will allow access.
For simplicity in troubleshooting, we'll propose putting no more than ten speakers on each cable run.
The problem is that they want us to reuse the existing speaker enclosures and just replace the speakers/transformers themselves. The existing wall mount enclosures are fairly well made of steel, so I can see why they want to keep them. The problem is, I was hoping to find a source for 8" speakers with transformers without any kind of grille or enclosure. I'm not having much luck. I'd hate to buy ones with grilles just to take them apart. Any ideas?
Ed Vaughn, MBSWWYPBX
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Joined: Sep 2005
Posts: 9,282 Likes: 5
Admin
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Admin
Joined: Sep 2005
Posts: 9,282 Likes: 5 |
Atlas has them like that. Nothing is excessive for the gov.
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Joined: May 2007
Posts: 5,052 Likes: 4
Moderator-1A2, Cabling
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Moderator-1A2, Cabling
Joined: May 2007
Posts: 5,052 Likes: 4 |
Ed -
Atlas, for sure, 8" speakers are readily available. if you have a problem locating them let me know and I'll see what I can do.
Also what I did on my last big PA job (JFK -AA. 5,000+ speakers) was, when we had a large grouping of speakers instead of looping them all (as the plans called for) or setting up individual runs, I had the guys run one feed to a central location, mount a 3 or 4 gang electrical box and then bring individual runs out to logical clusters. As long as the splice point is marked on the prints, troubleshooting is very easy.
And with that many speakers, you'll want the two most important pieces of test gear available - an impedance meter and an iPod. With those two you can get anything working.
Sam
"Where are we going and why are we in this hand basket?"
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Joined: May 2004
Posts: 750 Likes: 1
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Joined: May 2004
Posts: 750 Likes: 1 |
I have to ask. What do you use the IPOD for?
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Joined: Jul 2001
Posts: 3,322 Likes: 7
Moderator-Avaya-Lucent, Antique Tele
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Moderator-Avaya-Lucent, Antique Tele
Joined: Jul 2001
Posts: 3,322 Likes: 7 |
Presumably use it as an audio source to check the speakers for volume. Beats having a guy doing "Pete Moss to the Garden Center" all day long.
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Joined: May 2007
Posts: 5,052 Likes: 4
Moderator-1A2, Cabling
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Moderator-1A2, Cabling
Joined: May 2007
Posts: 5,052 Likes: 4 |
I have some test tones that I downloaded onto the iPod. Set on "repeat" it allows you to test a large group of speakers easily. When your'e done with the stress tests, pipe music through the speakers and if they sound good - they are good!
Sam
"Where are we going and why are we in this hand basket?"
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Joined: Dec 2002
Posts: 9,421 Likes: 1
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Joined: Dec 2002
Posts: 9,421 Likes: 1 |
I have a couple audio apps on my iPhone, most notably Tone Gen Pro.
I also have a db meter and a few others.
PS, "Pete Moss to the Garden Center"...love it!
Jeff Moss
Moss Communications
Computer Repair-Networking-Cabling
MBSWWYPBX, JGAE
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Joined: Jan 2010
Posts: 196
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Joined: Jan 2010
Posts: 196 |
I had the guys run one feed to a central location, mount a 3 or 4 gang electrical box and then bring individual runs out to logical clusters. As long as the splice point is marked on the prints, troubleshooting is very easy.
And with that many speakers, you'll want the two most important pieces of test gear available - an impedance meter and an iPod. With those two you can get anything working. Two excellent suggestions Sam. I'd also second Atlas Sound for a source of 8" speakers without grilles. The model C5AT70 is probably exactly what you are looking for. Your local Dukane Sound dealer is Life Safety Solutions ( https://tlglss.com/educational.asp) and I am sure they'd be happy to quote you on the model 5A607 speaker which is exactly what you need! 
Last edited by tim10; 04/13/13 01:46 AM.
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Joined: Feb 2005
Posts: 12,334 Likes: 3
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Joined: Feb 2005
Posts: 12,334 Likes: 3 |
Couple of things that come to mind here Ed. First, about the existing wiring. Most large amps require Class 1 wiring. Is what's there suitable- is it in conduit or other Chapter 3 wiring method? Are the amps you are contemplating Class 1? (Remember, if it doesn't say Class 2 or Class 3 wiring by the output is MUST be assumed as Class 1.)
The second question: is this a life safety system? If so you probably aren't qualified to install it and there are all kinds of design considerations way beyond a PA system.
-Hal
CALIFORNIA PROPOSITION 65 WARNING: Some comments made by me are known to the State of California to cause irreversible brain damage and serious mental disorders leading to confinement.
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