Measured differences between treble damping materials

I decided to do a simple comparison between different materials and their dampening characteristics. I did it in the simplest way ever, and just put my measurement mic in front of a tweeter, and put hung different materials over the tweeter for each measurement. I did 3 measurements per material and averaged them.

I first did a raw measurement with nothing covering the tweeter. Then I tested with 1, 2, and 3 layers of toilet paper, a coffee filter, and one layer of stiff felt sourced from Brainwavz HM5 cups (it's just a thick layer of good stiff felt).

Results below! I forgot to change the titles on the two last TP graphs, but obviously the not-green line is the filtered one








imgur album: http://imgur.com/a/cAift
.mdat file (only averaged responses): http://imgur.com/a/cAift

 

I'd be curious to see the difference between materials just hung in front, and materials stretched taught in a firm holder of some sort.

 

Why are wave patterns so common in noise attenuation?

I remember the Etymotic filters were the same.

http://rinchoi.blogspot.com/2012/08/the-effect-of-acoustic-dampers-on-iems.html



For many headphones 5Khz - 10Khz is the issue such as Beyerdynamic. Or you have planar magnetics that rise sharply and peak around 10Khz.

What ply is the toilet paper? What brand?

Wool felt is another common material used.

 

These are just simple measurements to get a rough idea of dampening shapes. This is closer to what the AUDIBLE differences are. It's really really hard to read the measurements without a lot of smoothing just because of how incredibly jagged everything becomes in the high end. Add to that how many of the more nuanced differences like added dips here and there will go away or shift entirely if you just move the mic or source a little, this is a more accurate average. I did look at them with many different smoothing levels to confirm that the 1/3 smoothing is still perfectly representative of the actual psychoacoustic differences the materials will make.

The toilet paper is "whatever we had hanging". I'm in Norway, so I'm not sure you'll be able to source it anyway