Film-Tech Forum ARCHIVE: Acoustical panel question...

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Posted by Tom Wienholt (Member # 1510) on 03-01-2007, 02:06 PM:

I would like to add sound absorbing material behind my auditorium screens on the walls. Also, I will be making small baffles for the stage speakers. I am not sure what type of acoustical material should be used for these purposes. I have read other forums discussing the issue that suggest using black duct liner. What exactly is this and where can it be purchased? Also, what are some other options? I am on a small budget so the least expensive but still effective material is needed. Any help would be greatly appreciated. Thanks.

Posted by Richard Fowler (Member # 893) on 03-01-2007, 06:13 PM:

Black fabric back duct liner is available from any air conditioning / heating distributor. You can also make acoustical panels with rigid aluminum foil backed fiberglas duct board from the same source.

Posted by Mark Gulbrandsen (Member # 72) on 03-01-2007, 07:18 PM:

FWIW: The price of fibreglas hasabout doubled in the last year. Many manufacturers of ready to hang panels prices have more than doubled.

Mark

Posted by Tom Wienholt (Member # 1510) on 03-01-2007, 10:19 PM:

Are there any companies that sell the acoustical material that I will need that anyone would recommend?

Posted by Cameron Glendinning (Member # 3516) on 03-01-2007, 11:05 PM:

quote: Tom Wienholt
I will be making small baffles for the stage speakers.

Well dont bother if they are small nor strong, I have found that baffles between 3 and 4 foot on each side re enforced with 2x4, will extend the bass response down into the sub bass, aka 30hz, Fiberglass is nice and strongly recomended but not vital a smooth surface can also work for wings.
I do not know US fire regulations but polyester, wool, fiberglass roof bats, would do the job, making it black with paint, or dropping black material over it would stop unwanted reflections.

If the wings are not made strongly, they will cause more problems, add resonences or even absorb bass. So a material at least as strong as the box. ie 18mm MDF with bracing (2x4) every 1 1/2 feet. structial strength is the key.

As for the walls, a thin material like masonite can be a good surface to mount duct liner to as absorbing bass can be a good thing, but its the highs that cause more discomfort to the audience. Also random angles or plasterwork shapes can break up this reflected sound.

The positioning of the horns on the stage speakers can reduce the amount of bounce in the first place.

Posted by Tom Wienholt (Member # 1510) on 03-02-2007, 05:38 PM:

Any recommended companies that sell acoustical material?

Posted by Tristan Lane (Member # 1169) on 03-03-2007, 12:33 AM:

Tom,
Richard just told you where to find acoustic absorbing material.

If you want to go with a dedicated supplier then check out; Whisper Walls, LBI/Boyd, PNC West.