| Wanted: Acoustical Engineer for Noise Abatement Issues [message #323314] |
Fri, 16 May 2008 04:17  |
Pascal Pincosy
Messages: 666
Registered: June 2005
Location: Berkeley, CA |
Has No Life |
|
|
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
--------------------------------
US Distributor: Trabes/MG Srl
Speaker Lifts-Truss-Roof Systems
|
|
|
|
|
|
| Re: Wanted: Acoustical Engineer for Noise Abatement Issues [message #323326 is a reply to message #323321 ] |
Fri, 16 May 2008 06:37  |
Pascal Pincosy
Messages: 666
Registered: June 2005
Location: Berkeley, CA |
Has No Life |
|
|
| Ivan Beaver wrote on Fri, 16 May 2008 03:53 |
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.
|
The building has already been encased in shockrete, so the mass is there. Unfortunately isolation is the problem. Long story short, the condo complex's foundation is physically connected to the foundation of the nightclub. When the nightclub's a rockin', the neighbors come knockin'.
Like I said, many thousands of dollars have already been spent trying to fix the problem. We made some progress by finding the resonant frequency of the nightclubs structure and dropping a notch filter at that frequency and at the harmonics, but there's still a long way to go. At this point, I'm looking to bring out the "Big Guns". I need someone who can not only grok the extremely complex situation, but can also take measurements of the vibrations and figure out where they're going, and where they came from. I'm not necessarily looking for someone local. I figure there are not many people/firms out there who are capable of dealing with this problem. I'll happily accept recommendations for the right consultant based anywhere in the country.
Know:Audio
--------------------------------
US Distributor: Trabes/MG Srl
Speaker Lifts-Truss-Roof Systems
|
|
|
|
| Re: Wanted: Acoustical Engineer for Noise Abatement Issues [message #323330 is a reply to message #323328 ] |
Fri, 16 May 2008 07:07 |
Pascal Pincosy
Messages: 666
Registered: June 2005
Location: Berkeley, CA |
Has No Life |
|
|
That solution is certainly under consideration. Problem is that we don't know exactly where said connection occurs, and the gap between the buildings is only a few inches wide. This solution would also require cutting an access hole in the side of the building. Said side of building is very thick shockrete.
This is exactly why we need an expert to come in and find a solution. Even if the answer is painful/expensive, at least money doesn't continue to be spent on futile measures.
Know:Audio
--------------------------------
US Distributor: Trabes/MG Srl
Speaker Lifts-Truss-Roof Systems
|
|
|
| Re: Wanted: Acoustical Engineer for Noise Abatement Issues [message #323335 is a reply to message #323314 ] |
Fri, 16 May 2008 07:34 |
 Tom Young
Messages: 1820
Registered: April 2004
Location: Oxford CT |
Has No Life |
|
|
There are a few very good acoustic consultants I know in northern CA. Try Chips Davis first.
http://www.chips-davis.com/
If you need other leads, give me a holler.
Tom Young
Electroacoustic Design Services
Oxford CT
Tel: 203.888.6217
Email: dbspl@earthlink.net
www.dbspl.com
|
|
|
| Re: Wanted: Acoustical Engineer for Noise Abatement Issues [message #323346 is a reply to message #323323 ] |
Fri, 16 May 2008 08:34 |
Brad Weber
Messages: 1315
Registered: December 2005
Location: Marietta, GA |
Has No Life |
|
|
The problem with that is that you are dealing with multiple paths and variations in the paths, even if you get it to work at that one point where the shaker is will that make things better or worse elsewhere?
Ivan was right on in his comments. Having worked on vibration isolation of everything from laundry equipment and generators sets adjacent to Operating Rooms to electron microscopes to a mechanical room over a broadcast studio to explosives training ranges, it seems that the only effective options are going to be providing an impedance mismatch, i.e. making the connection between buildings discontinuous, or isolating the source of the vibration or perhaps even a combination of the two.
There can be some easier tricks such as getting the sources away from being mid-span of the supporting structure where the structure itself is more easily excited and with greater amplitude, but one would have to see the particular installation to see if any of those might be effective.
There are a number of firms in CA that would be able to help you, you might want to start by looking at http://www.ncac.com and looking for firms that list vibration control as an area in which they offer services.
Brad Weber
muse Audio Video
|
|
|
|
|
| Re: Wanted: Acoustical Engineer for Noise Abatement Issues [message #323416 is a reply to message #323314 ] |
Fri, 16 May 2008 11:33 |
Charlie Zureki
Messages: 843
Registered: April 2008
Location: Detroit Area |
Has No Life |
|
|
Pascal,
You did say Vibrations...
If it's coming from the club, it's a safe bet that the energy is coming from the subwoofers.
You have a few choices, but I'd try the cheapest first. Contact a company in California that sells Vibration Isolators. They'll probably let you "try" them for a demonstration, and you'll be able to return them if they're not damaged.
There are many different ratings for these regarding weight capacities and Isolation frequencies. Install these under your stage, wings, or subs depending on how your equipment is set up.
You need to de-couple the energy from the floor. The concrete is your path for the Energy to travel to the Condos
If that doesn't help, it may be time to call in an Engineer with Vibration experience to take some measurements with a vibrometer or an accelerameter to a analyzer.
Try the Isolators first it may be an easy fix.
Good Luck,
Hammer
Be prepared, you'll need it!
|
|
|
| Re: Wanted: Acoustical Engineer for Noise Abatement Issues [message #323425 is a reply to message #323323 ] |
Fri, 16 May 2008 11:57 |
Charlie Zureki
Messages: 843
Registered: April 2008
Location: Detroit Area |
Has No Life |
|
|
Gene this active noise cancellation system won't work in this club/condo situation. His "Energy" is being transmitted through the floor, and foundation of the buildings. You'd have to run 180deg energy through the floor, and it still probably would not work to anyone's satisfaction.
Hammer
Be prepared, you'll need it!
|
|
|
| Re: Wanted: Acoustical Engineer for Noise Abatement Issues [message #323429 is a reply to message #323425 ] |
Fri, 16 May 2008 12:05 |
Tom Young
Messages: 1820
Registered: April 2004
Location: Oxford CT |
Has No Life |
|
|
Not to mention that active noise cancellation requires that you are within an area where the cancelling energy and source energy are out of polarity, or are phase-cancelled enough to work. In a larger space you may or may not be in this "zone".
Active noise cancellation has been demonstrated to be viable in very small acoustic environemnts such as headphones and car cabins, where your position (or that of your ears) is in the "zone", or null point.
Tom Young
Electroacoustic Design Services
Oxford CT
Tel: 203.888.6217
Email: dbspl@earthlink.net
www.dbspl.com
|
|
|
|
| Re: Wanted: Acoustical Engineer for Noise Abatement Issues [message #323441 is a reply to message #323416 ] |
Fri, 16 May 2008 12:49 |
Brad Weber
Messages: 1315
Registered: December 2005
Location: Marietta, GA |
Has No Life |
|
|
| Charlie Zureki wrote on Fri, 16 May 2008 12:33 |
Pascal,
You did say Vibrations...
If it's coming from the club, it's a safe bet that the energy is coming from the subwoofers.
You have a few choices, but I'd try the cheapest first. Contact a company in California that sells Vibration Isolators. They'll probably let you "try" them for a demonstration, and you'll be able to return them if they're not damaged.
There are many different ratings for these regarding weight capacities and Isolation frequencies. Install these under your stage, wings, or subs depending on how your equipment is set up.
You need to de-couple the energy from the floor. The concrete is your path for the Energy to travel to the Condos
If that doesn't help, it may be time to call in an Engineer with Vibration experience to take some measurements with a vibrometer or an accelerameter to a analyzer.
Try the Isolators first it may be an easy fix.
|
The subwoofers themselves don't weigh much so to get low frequency isolation from the isolators may require a large amount of isolator deflection, thus potentially making for a rather unstable mounting. You may look at an inertia base, basically a big, heavy concrete slab that the subs sit on and that is in turn isolated from the structure. This can usually make for more effective isolation when dealing with relatively light sources.
Brad Weber
muse Audio Video
|
|
|
Forum Home
Login
Forum Search
Register
FAQ
