R/E/P Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: [1]   Go Down

Author Topic: Helpful side effect  (Read 1558 times)

jetbase

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2454
Helpful side effect
« on: February 14, 2007, 10:19:49 pm »

I have set up a recording booth behind my control room. It's a bit makeshift at the moment (though very usable), & not that greatly isolated from the outside world, particularly through one side wall. I put in several panels from my old studio to deaden the room a bit (nothing fancy, basically old office partitions with foam & fabric attached - basically gobos). The room still had an unpleasant ring to it, which I determined to be from the ceiling (to floor). So, using what I had, I strung up a sheet of 100mm (4") Tontine Acoustisorb insulation, which runs the full length of the room & 1/3 to 1/2 the width & sits about 1" away from the ceiling. This got rid of the ring, & made the room sound quite suitable for recording.

Once I put the tontine up I noticed that noise from the outside world was greatly reduced, quite a dramatic difference in fact, even though this treatment was not on the side wall most prone to leakage from outside (& it was not even covering the entire ceiling). I'm guessing that the tontine is soaking up reflections which otherwise seem to amplify the outside sound? Interesting, & very helpful!
Logged
sleep is not an option

jwhynot: "There's a difference between thinking or acting dogmatically and drawing from experience."


Glenn Santry
http://www.myspace.com/glennsantry

franman

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 580
Re: Helpful side effect
« Reply #1 on: February 15, 2007, 11:08:04 pm »

Yes... although sound absorption inside the room doesn't directly affect sound transmission loss, quieting down the room can sometimes provide a subjective reduction in the noise tranmission... It's just as you stated, the room is now less reverberant and the noise that does get through your isolation partitions bounces around less so the room may sound quieter... and indirect benefit...
Logged
Francis Manzella - President, FM Design Ltd.
                 - Managing Director, Griffin Audio
fmdesign.com
griffinaudiousa.com

jfrigo

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1029
Re: Helpful side effect
« Reply #2 on: February 16, 2007, 12:05:47 am »

The math for this effect is easy too. For NR (Noise Reduction) isol(ation):

NRisol=TL+10 log A2/Sw

Where TL is the transmission loss of the wall, A2 is the total absorption in Sabins in the recieveing room, and Sw is the surface area of the common wall.

As Fran states, as you increase A2, the effective isolation also increases as the reverberant levels of Lp(receiver) are reduced.
Logged

franman

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 580
Re: Helpful side effect
« Reply #3 on: February 18, 2007, 12:56:34 pm »

Thanks for the math, oh MHA guru M(aster) H(andbook) of A(coustics)...
Logged
Francis Manzella - President, FM Design Ltd.
                 - Managing Director, Griffin Audio
fmdesign.com
griffinaudiousa.com

jfrigo

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1029
Re: Helpful side effect
« Reply #4 on: February 18, 2007, 08:27:12 pm »

franman wrote on Sun, 18 February 2007 12:56

Thanks for the math, oh MHA guru M(aster) H(andbook) of A(coustics)...


Is that math actually in MHA? As fabulous as that text is (definitely a classic all should own), I think he intentionally didn't put too much math in there apart from the basic frequency/wavelength, Sabine, room modes, and a bit of QRD stuff. A quick glance at the index doesn't show a reference. My reference came mainly from back in my school days where it was in other architectural acoustics texts.

One of the great things about MHA is that you don't need to get bogged down in math. There's just a load of practical info, with easy to understand explanations, and practical examples. Still, nobody should be afraid of a little math. A lot of useful acoustics math is pretty easy.
Logged

franman

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 580
Re: Helpful side effect
« Reply #5 on: February 21, 2007, 01:54:57 am »

Absolutely! ( I was guessing BTW!! ) Very Happy
Logged
Francis Manzella - President, FM Design Ltd.
                 - Managing Director, Griffin Audio
fmdesign.com
griffinaudiousa.com

Pages: [1]   Go Up