# Acoustic impedance of wool?

1. May 3, 2016

### Coolguynice

1. The problem statement, all variables and given/known data
I need this to find the the reflective coefficient and multiply this by 100 to find the percentage of original energy reflected back however i cannot find the acoustic impedance of wool no matter how hard i try.
2. Relevant equations
Im using the reflective coefficient formula which reads as ((Z2-Z1))^2/((Z2+Z1))^2 where z is a sound impedance. In this case Z1 is the sound impedance of air and Z2 is the sound impedance of wool. I also found a formula to calcualte acoustic impedance which reads as Z=density of material(pressure*speed of sound through the material) however it doesn't specify whether the pressure is a constant or not and like the acoustic impedance, i also cannot find the speed of sound through wool after all this time.

3. The attempt at a solution
Any help or directions to decent sources would be extremely helpful. I know exactly what to do but these lack of values is holding me back from finishing anything else. Any help would be greatly appreciated.

2. May 3, 2016

### Staff: Mentor

When you say "wool" do you mean natural fiber sheep's wool, or something like mineral wool or glass wool or fiberglass wool which are commonly used as acoustic insulation?

3. May 3, 2016

### Coolguynice

Glass or fiberwool would be the best but honestly, at this rate i would be fine with any value regardless of the type of wool. Also thanks for replying.

4. May 3, 2016

### Staff: Mentor

You may have to do some prowling through the search results, but try Google with a keyword phrase like "Acoustic impedance table wool".