| Forum: Installed Sound/Contracting |
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| Topic: Ceiling-speaker density - large hall |
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| Re: Ceiling-speaker density - large hall [message #323408 is a reply to message #323236 ] |
Fri, 16 May 2008 11:14 |
 Sebatian Ochoa
Messages: 7
Registered: September 2007 |
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I'll be taking measurements today, and i will post them as I get back. Is a 10.44 db variation acceptable for paging?
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| Re: Ceiling-speaker density - large hall [message #323423 is a reply to message #323408 ] |
Fri, 16 May 2008 11:52 |
Charlie Zureki
Messages: 266
Registered: April 2008
Location: Detroit Area |
Has No Life |
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Yes 10dB is plenty.
Cheers Hammer
Be prepared, you'll need it!
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| Re: Ceiling-speaker density - large hall [message #323456 is a reply to message #323423 ] |
Fri, 16 May 2008 13:08 |
Brad Weber
Messages: 1158
Registered: December 2005
Location: Marietta, GA |
Has No Life |
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What seems to be overlooked so far is that you are talking about announcements that have to be understood in a space with high ambient noise levels and limited acoustical treatment, so intelligibility may be much more important than coverage. I would be a little concerned about the resulting intelligibility with the wider spacing and variation in coverage.
Brad Weber
muse Audio Video
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| Re: Ceiling-speaker density - large hall [message #323476 is a reply to message #323456 ] |
Fri, 16 May 2008 13:44 |
Charlie Zureki
Messages: 266
Registered: April 2008
Location: Detroit Area |
Has No Life |
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Point Source from a height of 9ft. Each speaker covering an area of 15 x 15 feet, or 225sq' 
Sebastian said it was "quite noisy" , which is a subjective term, that is the reason I told him to take some measurements with a meter.
In this case, all things being equal, intelligibility is directly proportional to coverage.
If his ambient levels fluctuate widely... then he should add more speakers.
Cheers,
Hammer
Be prepared, you'll need it!
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| Topic: Optimizing An Old Gym System |
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| Re: Optimizing An Old Gym System [message #323322 is a reply to message #323296 ] |
Fri, 16 May 2008 05:59 |
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Ivan Beaver
Messages: 4189
Registered: January 2005
Location: Atlanta Ga area |
Has No Life |
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GOOD LUCK. If you are not wanting to move anything, the ONLY thing you can do is to adjust the crossover freq.
The MOST you can expect out of that is to get a little bit of intellgability. Run the horns down to around 250Hz and don't turn up the bass cabinets to loud.
That is ASSUMING that they are true paging horns and not HF horns. IF HF horns, I would walk away-because you will be blamed for anything that happens, or lack thereof.
Can I have some more talent in the monitors--PLEASE?
Ivan Beaver
dB Audio & Video Inc.
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| Re: Optimizing An Old Gym System [message #323333 is a reply to message #323296 ] |
Fri, 16 May 2008 07:26 |
Tom Young
Messages: 1694
Registered: April 2004
Location: Oxford CT |
Has No Life |
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How certain are you that the VOT's do not have HF horns within them ? If they do, there will be a crossover mounted on the back of the enclosures with input jacks and a HF level control.
How certain are you that the "paging horns" are not Altec 811 (or similar) HF horns ? These may look to you like paging horns but they may be better than that.
Tom Young
Electroacoustic Design Services
Oxford CT
Tel: 203.888.6217
Email: dbspl@earthlink.net
www.dbspl.com
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| Re: Optimizing An Old Gym System [message #323431 is a reply to message #323333 ] |
Fri, 16 May 2008 12:09 |
Charlie Zureki
Messages: 266
Registered: April 2008
Location: Detroit Area |
Has No Life |
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Dan, you need a Genie to actually see the boxes and components up close... and while you have the Genie out... you might as well re-position the boxes/ horns.
The boxes are definately in the wrong spot... time alignment issues. Not that it wouldn't be nice to have some extra gear, but the Money would be better spent on moving the speakers as Ivan stated in his post.
Good Luck,
Hammer
Be prepared, you'll need it!
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| Re: Optimizing An Old Gym System [message #323446 is a reply to message #323296 ] |
Fri, 16 May 2008 12:57 |
Brad Weber
Messages: 1158
Registered: December 2005
Location: Marietta, GA |
Has No Life |
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Just to add to the great information you already received, in general it is impossible to properly address crossovers, high and low pass filters, etc. without knowing a lot more about the actual products and system configuration involved. If those are indeed paging horns then you might even have a number of different drivers that could be mounted to the same horn with very differing responses. It would most definitely be real useful to verify the existing products and wiring.
Brad Weber
muse Audio Video
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| Re: Optimizing An Old Gym System [message #323451 is a reply to message #323431 ] |
Fri, 16 May 2008 13:01 |
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Dan Brandesky
Messages: 683
Registered: February 2006
Location: Lima, OH |
Has No Life |
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Yeah, I figured it would be a rather challenging setup.
I can see from the ground that the horns are Atlas horns, and it would seem most logical that they would install paging horns in a gym. I doubt the system was originally designed for music playback really. I might be able to get a picture of the Altec boxes sometime, but from what I can see, there is a LF driver set back in the cabinet, and at the bottom there is a small band of grille cloth, I'm guessing for a port, but I could be wrong. I might be able to see if I can turn off/disconnect the paging horns and see what the Altec boxes sound like alone. I will probably be able to start messing with this setup maybe next week, so I'll post back with more info as I find out more.
-Dan
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| Re: Optimizing An Old Gym System [message #323479 is a reply to message #323451 ] |
Fri, 16 May 2008 13:54 |
Tom Young
Messages: 1694
Registered: April 2004
Location: Oxford CT |
Has No Life |
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If the Altec VOT's have a HF horn inside, these may be blown. So listening may tell you nothing.
Again: if these are 2-way "fullrange" versions of the VOT, they will have an Altec crossover installed into the back. Finding this is *evidence* that there may be a HF horn on the inside as well as the horn-loaded woofer. You still need to determine that the HF horn was not removed and that it is functioning.
Your chances of achieving something workable are much better if these are functioning 2-way VOT's. Ohterwise, I think you are way too restricted in what can be achieved.
Tom Young
Electroacoustic Design Services
Oxford CT
Tel: 203.888.6217
Email: dbspl@earthlink.net
www.dbspl.com
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| Re: Optimizing An Old Gym System [message #323482 is a reply to message #323479 ] |
Fri, 16 May 2008 13:58 |
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Dan Brandesky
Messages: 683
Registered: February 2006
Location: Lima, OH |
Has No Life |
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Thanks Tom. So does anyone know, just to narrow down the possibilities, if there ever was a VOT model that only had a LF driver with no HF?
-Dan
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| Re: Optimizing An Old Gym System [message #323487 is a reply to message #323482 ] |
Fri, 16 May 2008 14:14 |
Tom Young
Messages: 1694
Registered: April 2004
Location: Oxford CT |
Has No Life |
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The VOT was widely used during its hayday and I think it was avaliable in three forms: with no HF horn/driver, with a HF horn/driver bolted on top and with the HF horn/driver installed into the grill-cloth covered "port". But I am not 100% sure about the last option. I may be confusing this with JBL, who offered a horn loaded system (4560) configured these ways.
You can figure this out by googling on "Altec Heritage" and visiting the website where pretty much all of the spec sheets and catalogs for Altec and JBL are archived.
Of course once you determine if this option was provided by Altec, you still are faced with the possibility that the installer "customized" the two VOT's in this system and they do or do not have a HF horn inside. Believe me; there were many such hot-rodded VOT's around back then.
My gut tells me the original installer was not lame enough to rely solely on Atlas paging horns for HF's / intelligibiity and that you will find HF horns in the VOT's. But I am not sure why I am so optimistic....... there were just as many (or more) "clowns" around back then.
Tom Young
Electroacoustic Design Services
Oxford CT
Tel: 203.888.6217
Email: dbspl@earthlink.net
www.dbspl.com
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| Re: Optimizing An Old Gym System [message #323496 is a reply to message #323482 ] |
Fri, 16 May 2008 14:42 |
Brad Weber
Messages: 1158
Registered: December 2005
Location: Marietta, GA |
Has No Life |
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| Dan Brandesky wrote on Fri, 16 May 2008 14:58 |
Thanks Tom. So does anyone know, just to narrow down the possibilities, if there ever was a VOT model that only had a LF driver with no HF?
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Sure, there were several, in fact many of VOTT speakers were a low frequency enclosure with a horn mounted on top. The traditional 828 cabinets did have grille cloth across the bottom but it was about half the enclosure height and not just a narrow band. The 816 and 817 models had smaller ports across the bottom but no grille cloth.
Brad Weber
muse Audio Video
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| Topic: Wanted: Acoustical Engineer for Noise Abatement Issues |
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| Wanted: Acoustical Engineer for Noise Abatement Issues [message #323314] |
Fri, 16 May 2008 04:17 |
Pascal Pincosy
Messages: 593
Registered: June 2005
Location: Berkeley, CA |
Has No Life |
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I'm looking for an Acoustical and/or Structural Engineering Consultant to make recommendations on how to proceed with dealing with a problem with bass vibrations traveling from one building to another, the two buildings in question being a nightclub and a condo complex. I'm looking for someone who can come in and take measurements and make solid recommendations on how to proceed with regard to future soundproofing efforts. Funding is not an issue. Tens of thousands of dollars have already been spent trying to fix the problem to no avail, so guesswork isn't going to cut it at this point. I need the best in the business. Any recommendations would be greatly appreciated!
Know:Audio
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US Distributor: Trabes/MG Srl
Speaker Lifts-Truss-Roof Systems
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| Re: Wanted: Acoustical Engineer for Noise Abatement Issues [message #323321 is a reply to message #323314 ] |
Fri, 16 May 2008 05:53 |
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Ivan Beaver
Messages: 4189
Registered: January 2005
Location: Atlanta Ga area |
Has No Life |
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| Pascal Pincosy wrote on Fri, 16 May 2008 05:17 |
I'm looking for an Acoustical and/or Structural Engineering Consultant to make recommendations on how to proceed with dealing with a problem with bass vibrations traveling from one building to another, the two buildings in question being a nightclub and a condo complex. I'm looking for someone who can come in and take measurements and make solid recommendations on how to proceed with regard to future soundproofing efforts. Funding is not an issue. Tens of thousands of dollars have already been spent trying to fix the problem to no avail, so guesswork isn't going to cut it at this point. I need the best in the business. Any recommendations would be greatly appreciated!
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Those are the two key words! In order to stop bass vibrations you need physical isolation between the two. No amount of absorption, diffusion etc is going to do any good for low freq.
Depending on the particulars some SERIOUS mass might help, but that depends on the particulars.
You are correct in getting somebody in who know what they are doing and has dealt with this before.
Be sure to tell them upfront what the problem is and what you expect from them-result wise.
Can I have some more talent in the monitors--PLEASE?
Ivan Beaver
dB Audio & Video Inc.
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| Re: Wanted: Acoustical Engineer for Noise Abatement Issues [message #323323 is a reply to message #323314 ] |
Fri, 16 May 2008 06:06 |
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Gene Hardage
Messages: 204
Registered: February 2007
Location: St. Pete-A-Bug FLA |
Has No Life |
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This very problem is happening at a club/hotel near us. My speaker buddy is experimenting with something like the noise canceling headphones on a larger scale with speaker-shakers to be mounted on the ceiling between the two. Too soon to tell if it's gonna work properly. Keep us posted on what the pros in your area do to solve this common problem.
Gene SARASOTA SLIM Hardage
http://www.SarasotaSlim.com
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