To be honest, hard plastic as the one used for fixating the headband on the HD800 don't damp anything.
The damping is a property of the material that translate deformation of the material into heat dissipation - that won't happen with hard plastic.
 
How many at Canjam did compare your Sigma to your Sigma/sorbothaned, and how many prefered the sorbothane?

soren_brix said:

  To be honest, hard plastic as the one used for fixating the headband on the HD800 don't damp anything.
The damping is a property of the material that translate deformation of the material into heat dissipation - that won't happen with hard plastic.
 
How many at Canjam did compare your Sigma to your Sigma/sorbothaned, and how many prefered the sorbothane?

Click to expand...

I have no idea then what Sennheiser is actually doing to damp the HD800.   Sometimes companies spread disinformation to throw competitors off.
 
I spent 2 solid days at Canjam, about 8 hrs on Staurday and 6 1/2 hrs on Sunday almost constantly demonstrating. I mostly showed the damped 007, running off the Stax 717 amp, and the Sigma/404. and undamped Sigma pro, each running off a separate Stax SRM1 Mk2.  The sources were 2 Woo Audio transports and Musical Fidelity DACS.   The Sigma SRM's were fed from the same cd system. Some poeple plugged their phones or Ipods into the amps. The 2 Sigmas were the closest I could get to having  identical damped and undamped phones.
 
Everyone seemed to think the sorbed phones were great, especially the 007.  As to the number I wasn't counting.  I had no complaints at all about the sound of the damped 007.  Only one person didn't like the Sigma although he seemed happy with the 007.  When I checked his music it was a recording of some Asian singer, singing very quietly and there was tape hiss on the recording. Certainly not  Hi-Fi source material.  Possibly 50-70 people in total sat down and listened on the 2 days.  As regards the difference between the Sigmas,  it's easier to recall that maybe 2 people said they couldn't tell the difference between the 2 Sigmas. Some didn't say one way or the other.
 
Some people had never heard electrostatics and even fewer had heard a Sigma. I had the only Sigmas in the show and there were a lot of comments about never having hear anything like them.  One guy had an old pair of low bias, said they didn't sound anything like this  and wanted to know how to get his rebuilt.
 
More impressive to me was that I had about 7-8 people who identified themselves as professional engineering types  in audio.  All of them heard the difference between the Sigmas and agreed with my Newtonian explanation. I remember Frank Cooter who had his huge stat amp with the 009 on display coming over and spending about 10 minutes going back and forth between the 2 Sigmas and finally saying " I think you're on to something."   This is his amp:
 

 
 
At one point I took the damped SRXIII pros over to the Woo Audio table where they had their less expensive tube stat amp on display. They were using it with  a Lambda 404 LE  and it sounded very good.  But the SRX  was far crisper in sound and the 404LE was muffled by comparison.  I gave it to the guy who was manning the station and his face lit up when he heard them  and said these are really good.  Then he started taking selfies of my phones on his head.
 
I was able to spend about 10 minutes with Cooter's amp comparing the damped 007A with the 009 and it was no better overall than the damped 007. The 009 seemed to have a slightly more extended treble but the damped 007 had a slightly more dynamics. I really needed more time  and I also wanted to hear my other phones on his amp.  Now if you damp the 009 you could have something else again.
 
I  actually listened to very little at the Canjam because I stayed with my gear almost the whole time, watching other people use my phones and talking to folk.  It was fun but exhausting.  This is a link to my facebook posting of the event:
 
https://www.facebook.com/media/set/?set=a.962642790421786.1073741911.100000282228003&type=1&l=4957838283
 
 
 
 
 
 
 
.

Nice wrap up of your Canjam meet
 
Sounds like the more experienced people does agree that the sorbothane is improving the headphones.
 
Interesting that the SRX/Sorb turned out to be more clear and crisp in comparison with 404LE (I haven't heard either), and the 404LE sounding muffled.
My own expereince sorb'ing the 404 (not LE) is that the sound gets more clear, less coloration ... I guess the opposite of sounding muffled
The same experience with the 202.
The reason why I haven't written alot about 202/404 is that I don't listen to either very often. I just thought I try it out since it's so damn easy to do the mod on those.
 
The Sigma's are a hole different ballgame, since they are a bit tricky to say at least; both in adding the sorb but also ensuring that the glaswool is still in proper place (this is also affecting the sound)
The 007 are also rather tricky mainly due to mounting the pads. When applying sorb to the black metal plate you end up lifting the pads or put extra pressure on the pad itself ... so is the sound better due to sorb or due to the pads being a bit pressed together? The pads are damping the black metal plate, and probably even more when you wear the headphones, so I am not entirely convinced that it is actually the sorb itself that makes the difference but rather the space they fill in - have you tried removing the sorb from the black metal plate and stuff in between the pads and the protective fabric? I guess you'll end up hearing the excact same improvement ...

soren_brix said:

  Nice wrap up of your Canjam meet
 
Sounds like the more experienced people does agree that the sorbothane is improving the headphones.
 
Interesting that the SRX/Sorb turned out to be more clear and crisp in comparison with 404LE (I haven't heard either), and the 404LE sounding muffled.
My own expereince sorb'ing the 404 (not LE) is that the sound gets more clear, less coloration ... I guess the opposite of sounding muffled
The same experience with the 202.
The reason why I haven't written alot about 202/404 is that I don't listen to either very often. I just thought I try it out since it's so damn easy to do the mod on those.
 
The Sigma's are a hole different ballgame, since they are a bit tricky to say at least; both in adding the sorb but also ensuring that the glaswool is still in proper place (this is also affecting the sound)
The 007 are also rather tricky mainly due to mounting the pads. When applying sorb to the black metal plate you end up lifting the pads or put extra pressure on the pad itself ... so is the sound better due to sorb or due to the pads being a bit pressed together? The pads are damping the black metal plate, and probably even more when you wear the headphones, so I am not entirely convinced that it is actually the sorb itself that makes the difference but rather the space they fill in - have you tried removing the sorb from the black metal plate and stuff in between the pads and the protective fabric? I guess you'll end up hearing the excact same improvement ...

Click to expand...

At the moment I am at a good place having sorbed all my phones to.my satisfaction. I look forward to other people working out the kinks or finding better ways. 
 
You are correct, there is a spacing issue with the mod I  did for the 007. You are actually changing the resonant cavity somewhat. That is true whenever you sorb the inside of a phone, as opposed to putting it on the exterior.  
 
You are also changing the mass of the phones.  A couple of people suggested to me that the bass problems I sometimes found with sorb could be related to this i.e. I was hitting some resonance peak when I added too much sorb. 
 
While, as you say, just sticking sorb on things is not rocket science, figuring out all of what is going on is complicated.

Please read: http://www.head-fi.org/t/677809/the-stax-thread-iii/2040#post_10459375
And comment in rgrds to the sorb under the pads ....

Originally Posted by soren_brix
 
"Sounds like the more experienced people does agree that the sorbothane is improving the headphones."
 
I really didn't get any arguments against this,  and the more experienced people seemed to see the point.
 
 
"Interesting that the SRX/Sorb turned out to be more clear and crisp in comparison with 404LE (I haven't heard either), and the 404LE sounding muffled.
My own expereince sorb'ing the 404 (not LE) is that the sound gets more clear, less coloration ... I guess the opposite of sounding muffled
The same experience with the 202.
The reason why I haven't written alot about 202/404 is that I don't listen to either very often. I just thought I try it out since it's so damn easy to do the mod on those."
 
Even without sorb the SRXII pro is  very smooth across the middle although lacking deep bass.  The low bias SRX III was sold with a portable amp as a monitor phone.  The high bias model was made in very small numbers before Stax went to the Lambdas.   It has a better bass ( but is still no bass monster) and it may be a bit peaky at  about 2 kHz.  Adding sorb gets rid of some of its raspiness and adds some dynamics and  it is quite addictive.

soren_brix said:

Please read: http://www.head-fi.org/t/677809/the-stax-thread-iii/2040#post_10459375
And comment in rgrds to the sorb under the pads ....

Click to expand...

I have followed this thread. I would suggest that the opposite is true as well, i.e that while adding sorb, where I do on the 007, changes how the pad sits on these phones, changing the pad foam, irrespective of adding sorb, can change the damping too.
 
I am fairly sure that the main effect of sorbothane is damping for this reason.  My first efforts at using it were clamping it on the headband of the 007.  I also tried clamps on the body of the Sigmas and earcup of the 007.  Adjusting the tightness of the clamps changed the tonal characteristics even though this does not affect mass or any other aspect of system. The best explanation of this to me is that it changes the elasticity of the sorb as well as the firmness of its contact with the surface of the earcups.
 
 
 

 

 
However I recognize that other factors are at work here.  Probably the best way to do a  controlled study of absorbtion vs other physical factors would to compare 2 different types of sorbothane, of the same thickness but different duro (softness) .

Tachikoma said:

 
Re: damping headbands, I think it'd be more efficient to fashion sorbothane washers for the headband screws than to stick clamps on the headband.

Click to expand...

 
I think that both Stax and Sennheiser, on the HD 800, used metal bands  because they wanted a very rigid headband. Sennheiser however realized this would cause a problem and thus they damped their headband. Stax missed the boat on this.
I am sure that a manufacturer could come up with a better system than my homemade clamps.  Sennheiser's method is a sort of clamp too although it appears to use a hard plastic material with good damping qualities., or so they say.