DA have any acoustic analysis of reflections off of wood + other materials?

[spice house]

I'm looking for full spectral analysis of absorption and/or reflections off of various types of finished, unfinished, and rough woods and perhaps other materials

The best I can find are absorption coefficients for different materials in a a limited freq range, which is far too limited in my mind.

I have a hard time believing that there are no detailed studies on this, but I can't find one

[SörenHjalmarsson]

Flooring question
RealTraps - Does Wood Really Sound Warm?

[Adhoc]

There is a huge amount of different materials in the excel file here:
http://www.gearslutz.com/board/7351409-post20.html

[spice house]

Originally Posted by Adhoc

There is a huge amount of different materials in the excel file here:
http://www.gearslutz.com/board/7351409-post20.html

Wow! Quite extensive. I'll have to take a look through there

Great resource I'm saving that one! but the just have general 'wood' and stop at 4k or 8k

[Dange]

Can we ask what you're looking for the data for? It might help as we can suggest other ways to achieve your end goal

[spice house]

I'm essentially looking for the quantified effects of building rooms out of different materials and the textures. However I don't really want to debate the merits of that goal. I can't find data on the quality of reflections especially in the high range where the greatest differences are kiekly to lie. Just looking for a detailed analysis of what differences exist. I wouldn't be surprised if an analysis does not exist because many of the differences would be very small and not worth investigating

Sent from my Galaxy Nexus using Gearslutz.com

[Ethan Winer]

Originally Posted by spice house

I wouldn't be surprised if an analysis does not exist because many of the differences would be very small and not worth investigating

If you see my Surface Reflectivity article (Does wood sound warm?) that Sören linked to, you'll see that most non-absorbing surfaces reflect the same within less than a dB. I classify that as "very small," as you said.

--Ethan

The Acoustic Treatment Experts

[spice house]

Originally Posted by Ethan Winer

If you see my Surface Reflectivity article (Does wood sound warm?) that Sören linked to, you'll see that most non-absorbing surfaces reflect the same within less than a dB. I classify that as "very small," as you said.

--Ethan

The Acoustic Treatment Experts

Thank you Ethan, I have seen that article. I find it lacking because it is essentially a discussion of absorption coefficients, with reflections being extrapolated mathematically, lacks measurements of actual rooms, does not go above 4k, only discusses frequency, and is limited to 6 'snapshots' at certain frequencies. No realistic conclusion can be drawn from such limited data and flawed method of reflection analysis.

Tests conducted like the rt60 analysis below that article are much more revealing, the waterfall plots are especially enlightening.

Most importantly, these analysis lack 'human', or psycho-acoustic, testing - would the human ear be able to distinguish the reverberations in a glass room and from a wooden room? Though your analysis would suggest there is only a seemingly tiny measurable difference, I would expect the ear to perceive something clearly different.

[Dange]

The absorption coefficient is the reciprocal of the reflection coefficient. General acoustic practice is to work with absorption coefficients, so you probably turn up more information looking for high frequency absorption coefficients of materials. r =1/a

Also at higher frequencies diffraction plays a big part. The texture of the surface will be important. You could look at it as having two extremes, subtle textures of wood grain at one end and a QRD diffusor at the other.

Don't have any specific links to hand but maybe that will help with Google searches.