Several weks ago Jeff was kind enough to send me a scanned image of the subject report. JEff asked that I do not publically distribute the copyrighted document without permission from USG.
After several weeks of trying to get a response by email from anyone at USGI just got off the phone with Richard Master, head of Architectural Design at USG.
He has given permission to publically distibute the scanned image of the USG paper on the effects of density on sound isolation!
I do not know when I will be back at Aaron (my computer) however I sent a copy of the file to Steve, so it can be posted and added to archives etc!
Teh key thing abotu the brochure is that includes two figures that are not ont he posted compy of the report. The figures clarify somehting that was not clear to many of us, in tha tthe report indicates that 2.5 pcf material is best for sound isolation. Looking a the figures, what the report is saying is that for sound REDUCTION, 2.5 pcf material 3" thick provides the most cost effective (in other words to the reports well definded criteria) natural characteristic to the transmitted sound, to be least objectionable.
IF you are seeking significant ISOLATION, then denser material, up to 4 pcf in the study, willl provide usefull increased LF absorption and thicker is better. In the graphs, going from .7 pcf 3" to 4 pcf 6" (as I remember) increase the isolation at 125 Hz by about 8 dB. Teh higher frequencies have much greater icreases in isoaltion, but those are not of concern to us. The normal construction already provides enough isolation, if the wall is designed for effective LF TL.
Steve:
Hopefully you will post the file shortly. If I don't get a chance, could you send a copy to Dan, Eric or Scott at Studiotips for them to archive?
Jeff:
Thanks alot, you are a great help inlearning
Joyfully isolated Andre
USG Density Report
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