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thomas northward

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Posts: 140 Member Since: 10/02/2011

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Nov 3 11 9:23 AM

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I thought it would be useful to have a space where we can all store and share documents of interest on the subject of Acoustics in general, Room Acoustics and Studio Acoustics in particular.

Just be careful that the documents you post are in the public domain.

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thomas northward

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Posts: 140 Member Since:10/02/2011

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Nov 3 11 9:34 AM

I'll start.

1- Auditory Distance Perception
Pavel Zahorik
University of Wisconsin - Madison

It may not seem linked to studio design at first, but it is :)
Put it in perspective.

2- Novel silencers and absorbers for wind tunnels and acoustic test cells
P. Brandstätt, H.V. Fuchs, M. Roller

That has a more obvious use. Although, in my personal experience, these systems are still rather unreliable in terms of theoretical behaviour vs real life behaviour. In short: a good system, but you have to 'learn it' in practice. And give yourself a good margin for error (which is called "wide Q tuning" in acoustics) and do not only rely on these for LF treatment in a room. Rely on both resistance to flow and pressure based absorbers. And all those somehow in-between.



Click here to view the attachment
Click here to view the attachment

Thomas Jouanjean Northward Acoustics

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strangeandbouncy

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Posts: 2,150 Member Since:02/02/2011

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Nov 3 11 9:47 AM

oooh, Thomas, you're spoiling us!

  I shall read that tonight before bed . . .

    too much cheese gives you nightmares . . . . . no matter how you cut it


   KIndest regards,


    ANdyP

Ruh Roh . . . . .

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dcollins

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Posts: 2,365 Member Since:27/01/2011

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Nov 4 11 2:40 AM

I'm sure I've posted this before, but it's a good example of wave motion of all kinds, and other pointy-headed-beard-scratching topics.

Has other good links at the bottom, as well.



DC

 davecollinsmastering.com


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dcollins

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Posts: 2,365 Member Since:27/01/2011

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Nov 21 11 3:38 AM



I saw this stuff last week at Interbee, and the absorption they were getting from 1" sheets was pretty impressive:




DC

 davecollinsmastering.com


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dcollins

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Posts: 2,365 Member Since:27/01/2011

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Nov 21 11 4:51 PM

Does that system imply an engineered / forced specific mechanical dispersion of the energy within the wall?

-thomas_northward

I don't know.   It's just a one inch (14.26 Hectare Metric) thick sheet of some fibrous material, but it had a remarkable amount of attenuation, especially at LF. The demo was just laying them over a floor wedge, but I have to say the results were surprising.  The dealer is in Pasadena and I'll try to arrange a sample for you to evaluate.


DC

 davecollinsmastering.com


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boggy

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Posts: 59 Member Since:03/01/2012

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Jan 4 12 11:52 AM


Some International/European standrads for listening rooms:

1. "Multichannel surround sound systems and operations", AES Technical Council, Document AESTD1001.1.01-10, New York.
2. “Methods for the subjective assessment of small impairments in audio systems including multichannel sound systems”, ITU-R Recommendation BS.1116 (rev. 1), ITU, Geneva, 1997.
3. W. Hoeg, L. Christensen, R. Walker, “Subjective assessment of audio quality– the means and methods within the EBU”, EBU Technical Review Winter 1997, pp. 40-43.
4. "Listening conditions for the assessment of sound programme material: monophonic and two–channel stereophonic", EBU Tech. 3276 – 2nd edition May 1998, European Broadcasting Union, Geneva, Switzerland

Hope this helps someone

Cheers. 

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dandan

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Posts: 74 Member Since:02/02/2012

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Feb 4 12 6:31 PM

An online Porous Absorption Calculator written by Demetris. 
It does layers, airgaps, a choice of algorithms, includes Random Incidence. 

http://www.stanleyhallstudios.co.uk/pacalc/

You will need Gas Flow Resistivity figures for your fibre of choice. 
But for a quick start,  try:- 
25000 Rayls for 50Kg 703 type products
50000 Rayls for 100Kg 705 type products. 

There is a huge collection of real Gas Flow Resistivity numbers for many fibres here.
http://www.gearslutz.com/board/studio-building-acoustics/625978-common-gas-flow-resistivity-numbers.html

DD



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bill mueller

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Posts: 4,350 Member Since:20/01/2011

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Feb 5 12 11:43 AM


After unpacking, I did find this brochure.  A little worse for wear, but there it is:
[image]
[image]

-dcollins


This graph does NOT explain the videos that I saw. Nearing 100% absorptivity at 300hz is not unusual. The videos are VERY unusual. Odd.

Bill

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