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Research regarding Fiberglass insulation and harmonic absorption? [message #23119]

Tue, 22 August 2006 21:19

Pinky
Messages: 10
Registered: May 2009

Chancellor

Does anyone know of any research which shows the varying kinds of sound insulations including Fiberglass on the absorption or lowered transmission of harmonics and harmonic distortion, and especially broken down into even ordered(2, 4,6,8,etc) and odd ordered(3, 5, 7, 9, etc)?

Pinky

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Re: Research regarding Fiberglass insulation and harmonic absorption? [message #23121 is a reply to message #23119]

Wed, 23 August 2006 16:55

Bill Fitzmaurice
Messages: 335
Registered: May 2009

Grand Master

Fiberglas and other damping materials have no way of knowing whether the waves they damp are fundamentals or harmonics or, if they are harmonics, which.

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Re: Research regarding Fiberglass insulation and harmonic absorption? [message #23122 is a reply to message #23121]

Wed, 23 August 2006 17:38

Pinky
Messages: 10
Registered: May 2009

Chancellor

Why? Fiberglass and other materials are permeable to different frequencies at different rates, so their damping characteristics tend to vary by frequency.

In electricity, odd ordered harmonics tend to produce more heat than even ordered harmonics. And Fiberglass absorbes more heat than fiberfill.

Is this your opinion, or is there measurement data to suggest this to be true?

Pinky

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magnitude of THD: frequency dependent? [message #23123 is a reply to message #23122]

Wed, 23 August 2006 17:52

Pinky
Messages: 10
Registered: May 2009

Chancellor

I recently read some research that suggested that the magnitdue of distortion was greater at the lower frequencies than at the higher ones. If this is the case, and distortion is frequency dependent, then fiberglas and other materials which are frequency dependent in regard to their damping characteristics, will be distortion absorbing at different levels dependent on frequencies of sound presented.

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Re: magnitude of THD: frequency dependent? [message #23124 is a reply to message #23123]

Wed, 23 August 2006 19:05

Bill Fitzmaurice
Messages: 335
Registered: May 2009

Grand Master

They don't absorb distortion, they absorb sound waves. They are unable to tell which sound waves are distortion and which are not, so rather than drive themselves crazy trying to tell the one from the other they just absorb all of them. The process is frequency dependant, they do better with high frequencies than low frequencies.

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