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_ Six _



Joined: 03/06/06
Posts: 1502
Transmission loss in acoustic materials
      #722036 - 31/03/09 07:43 PM
I have found an equation to calculate transmission loss however its units of mass are lb/ft squared.

TL (dB) = 14.5log M+23

where TL is the transmission loss in dB and M is the surface density in pounds per square foot.

Is there a more up to date version that uses metric units?


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mankind-nil



Joined: 07/06/06
Posts: 118
Loc: Edinburgh, UK
Re: Transmission loss in acoustic materials new [Re: _ Six _]
      #722628 - 02/04/09 10:53 PM
The transmission loss is also a function of frequency, so the equation you've provided doesn't really make sense to me.
Try here for a useful paper explaining transmission loss.

Equation 1 gives TL= 20 log10 (mf) - 48
where m is the mass (in kg) per unit area (in m2) and f is frequency (in Hz), though this equation is only valid for part of the frequency spectrum, as explained in the paper.

ps June '06 was a great time to join the forums (or is it fora?) !

--------------------
MacBook, Logic 8, headphones, too many ideas...
www.mankind-nil.co.uk


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_ Six _



Joined: 03/06/06
Posts: 1502
Re: Transmission loss in acoustic materials new [Re: _ Six _]
      #723127 - 05/04/09 07:30 AM
Thanks mate. That's what I was looking for.

The first equation doesn't include the frequency, that's why it doesn't make much sense. I haven't got the book to hand but it was detailing the density of a mass and the TL relationship.

Cheers for that paper. Exactly what I need


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mankind-nil



Joined: 07/06/06
Posts: 118
Loc: Edinburgh, UK
Re: Transmission loss in acoustic materials new [Re: _ Six _]
      #723389 - 06/04/09 10:49 AM
No probs, glad it helped.
All the best.

--------------------
MacBook, Logic 8, headphones, too many ideas...
www.mankind-nil.co.uk


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