Sound-proofing rooms: responses (Michael Kubovy )

Subject: Sound-proofing rooms: responses
From:    Michael Kubovy  <mk9y(at)FARADAY.CLAS.VIRGINIA.EDU>
Date:    Fri, 8 Nov 1996 10:26:09 CST

I am grateful for the useful responses to my question about sound-proofing a room that was not initially designed for that purpose. Since the responses overlapped in principle, but not in the practical advice offered, I thought that a summary might come in handy for some of you. **************** Date: 6 Nov 1996 08:34:15 U From: Robert Majors <Robert_Majors(at)> Michael, How to Build a Recording Studio on a Budget by F. Alton Everest. Jeff Cooper has a good book, but is out of print and I can't get even a used copy. Acoustic Systems for voiceover booths, doors, and the like. Bob Majors **************** From: Zacharov Nick NRC/Tre <Nick.Zacharov(at)> Date: Wed, 06 Nov 1996 17:13:31 +0200 Hi Gypsum, the material manufacturer have a very good practical application guide for how to obtain certain sound isolation levels using different constructions. Contact them directly for this book on acoustics isolation. This is very sound info, to begin with rgds Nick Zacharov Speech & Audio systems PO Box 100 Tel +358-3-272-5786 33720 Tampere Fax +358-3-272-5899 FINLAND email: nick.zacharov(at) ********************** Date: Wed, 6 Nov 1996 11:23:50 -0500 To: kubovy(at) From: Biao Tian PhD <biao(at)> Subject: Re: Re sound-proofing rooms Michael, You can try Attn. Michael Binns Acoustical Solutions, Inc 2720 Enterprise Parkway Suite 101 Richmond, VA 23294-6340 Tel: (804) 346-8350 (800) 782-5742 Fax: (804) 346-8808 They sell a variety of materials for acoustic insulation. Good luck Biao Biao Tian Ph.D. Georgetown University Medical Center Institute for Cognitive and Computational Sciences New Research Bldg, WP22A 3970 Reservoir Rd. NW Washington, DC 20007-2197 USA Phone: (202) 687-6438 Fax: (202) 687-0617 E-mail: biao(at) ************************* From: "Steven M. Boker" <sboker(at)> Date: Wed, 6 Nov 96 11:29:26 -0500 Hi Michael- The answer will depend on the SPL, frequency spectrum and your criteria for success. The simple answer goes like this. There are several variables you can affect which will have different outcomes. I have listed them in descending order of importance. These are also nested: if you haven't addressed higher priority items, there is no point in addressing lower priority items. 1. Air tight inner seal. The room must be as near to being air-tight as possible. Leakage from around doors, under walls, through air ducts, through electrical outlets, through light fixtures and switches, or any other hole in the inner seal will constitute the main source of acoustic transmission in most normal rooms. Imagine the room as a ballon that is being inflated and deflated thousands of times per second. If there are holes in the ballon, the sound pressure equalizes with the outside, thereby transmitting acoustic energy. 2. Rigid mass on inner walls. Once again think of the room as a balloon being inflated and deflated. The more the room's walls expand and contract, the more acoustic energy is transmitted to the air on the exterior surface of the wall. 3. Air tight, acoustically isolated outer seal. A outer layer to the room which is not connected to the inner layer by structural components, creates sort of an outer balloon around the inner balloon. The much reduced SPL at the surface of the inner wall is once again attenuated by the outer wall. 4. Rigid mass on the outer walls. 5. Repeat as needed. Some effect can be obtained by materials that attempt to absorb acoustic energy. Thus, after assuring yourself that the booth is airtight, covering the booth inside and out with acoustic foam (Markertech 800-522-2025) can help attenuate high frequency components. These materials will have little effect on low frequency components. Also, these will alter the acoustic characteristics of the interior of the booth (if that is of concern). Your best bet for real isolation is to build a small airtight room around the isolation booth using conventional frame and 5/8" sheetrock on both the inner and outer surfaces. Fill the space between the studs with fiberglas insulation to reduce standing waves. Good luck! Steve --- Steven M. Boker 219-631-4941 (voice) sboker(at) 219-631-8883 (fax) 219-257-2956 (home) Dept. of Psychology, University of Notre Dame, Notre Dame, IN 46556 ************************** Date: Wed, 06 Nov 1996 09:45:09 -0600 From: Fred Wightman <WIGHTMAN(at)> Michael: I've gone through similar thought processes lately. There aren't any good books, but the basic principles are simple. For isolation, think MASS! Put extra drywall on the walls on independent studs. Also, the door and its seal are VERY important. Call Industrial Acoustics in NY, talk to Ellis Singer 718-430-4531. They make excellent doors and seals. Put money there...the walls and ceiling you can do yourself. Fred Wightman **************************** Thanks again, |\ /| / Michael Kubovy, Professor of Psychology | \ / | / Dept. of Psychology, Univ. of Virginia, Gilmer Hall | \/ |/ Charlottesville, VA 22903-2477 | |\ off (rm 310): (804) 982-4729; lab (rm 319): 4751; fax: 4766 | | \ my homepage--http://www.Virginia.EDU/~mklab/kubovy/ | | \ General Psychology--http://www.Virginia.EDU/~mklab/101.dir/101.html

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