[richard51]

I was using 1 centimeter squares as a baseline generally.
=1 Inch seems like a lot/excessively large considering I often could not use many depending on headphone in question.
You do not want to go overboard on this stuff, for me it's incremental tweaking to a critical point, and over that line it can ruin the headphone's characteristic sound ( often overboard they possibly can all start to sound the same )
Speakers would obviously be a different case

I apologize it is my bad.... 1 cm also for me I wrongly wrote 1 inch....

 

[edstrelow]

I was using 1 centimeter squares as a baseline generally.
=1 Inch seems like a lot/excessively large considering I often could not use many depending on headphone in question.
You do not want to go overboard on this stuff, for me it's incremental tweaking to a critical point, and over that line it can ruin the headphone's characteristic sound ( often overboard they possibly can all start to sound the same )
Speakers would obviously be a different case

Why would speakers be different from headphones?

 

[chrismini]

(it is possible to made the cut cleaner than mine with a razor blade..)


How to make a simple filtering space with many pieces of damping sorbothane : 6 RULES: 1 Many small pieces works better than more large one 2 too big mass of sorbothane does not work well , because too much is worse, (too much damping is a catastrophy, blutak mod for example is damping mod hence +sorb mod maybe too much damping simultaneous mod) and 3 the right thickness and duro...mine is 30 duro,1/8 inches for the metallic cup of the HE400, i had not try higher duro because i think the 30 duro work so well for me 4 and not more than 65% of the surface covered by sorbothane and probably around 50% or a little more is way better ....5 cut rule modulo 6 : with a razor blade or an exacto you cut a rectangular pieces in 6 little squares. ( it is not necessary to cut it before sticking it to the headphone, it was more easy for me to cut it after because i want them very close one another)I had originally stick 4 pieces of sorb at the bottom of the hoop, i cut now the four rectangular pieces of sorb in 6 pieces each, hence at one level i have 4 pieces of sorb, at another level i have divided these 4 pieces of sorb in 24 pieces, and i think that the mass of sorb act at one level as a 24 frequencies filtering mass, at another level act like an agglomerate 4 filtering frequencies mass of sorb... the principle is simple : divide the mass in cutting it in 6...

i am no engineer but the end result was extraordinary...clear sound across the board...that is my experience... The filtering of frequencies is not optimalized if the mass of damping sorb is too much big for the space damped or too homogeneous...In short i think the agglomerate of 48 located masses(6X8 on each cup) absorb better some higher vibration and the 4 little masses in the upper part of the cups and the 4 in the lower part of the cup act like 8 separate units and absorb better some other bass vibration... In short the GOLDEN RULE :cutting in 6 the damping mass of sorbothane transform it in a filtering space for various resonance. Effectively the form of any piece of sorbothane play a major role in vibration absorption.If for example the cuts were not totally completed and if the 6 little pieces are always partly linked together because the cutting was not absolutely complete the lack of clarity of the highs frequencies will be evident in a less detailed soundstage ...

Added 24oct: It seems that the filtering effect of the highs are better realized for me with this design cuts :



the highs are clearer and the bass untouched or less marked by these cuts, a rectangular piece of sorb cutted in 6 little squares.... i had translate all i had previously written in this post with my new experience (4 into 6 pieces) this is way better mod that clearly made an improvement of the definition of soundstage, if higher frequencies are more clearly defined, soundstage and localization of instruments are better , hence the filtering effects of dividing strip of sorb in 6 is an astounding improvement....

rule 6 : necessary to square all pieces of sorb,never sticking an integral piece of sorb without cutting in 6 or the sound will be more muffled; the filtering of the sound makes all frequencies more organic and will offer to you a more airy sound (Of my 8 pieces of sorb when 2 or 3 has been stick without being cutted in 6 the effect is immediately audible the sound was less airy less clear) . But i think, i had not try that, it is intuitive speculation, that the cut in diagonals will be better for the filtering effect : ( if someone try that let me know the results, i dont have leftover sorb to try )

i am no engineer but the end result was extraordinary...clear sound across the board ON MY 2 DIFFERENT headphones...that is my experience... The filtering of frequencies is not optimalized if the mass of damping sorb is much too big for the space damped or too homogeneous, that is the fundamental rule of rules...In short i think the agglomerate of 6 little squares act like one located mass and absorb better some bass vibration and the 6 separate little masses in each of the 4 upper and 4 lower rectangular pieces absorb better some other higher vibration... In short the GOLDEN RULE cutting in 6 the damping mass of sorbothane transform it in a filtering space for resonance. Effectively the form of any piece of sorbothane play a major role in vibration absorption (the sorbothane site affirmed that if i remember). I am no scientist, it is only my explanation...

It is an experiment in relation with the basic material of your headphone, plastic or metallic, the densities of your headphones, etc,and you must explore by Yourself and experiment, and READ the thread of Edstrelow to know the basic...People dont read these days... i put the sorb. outside BECAUSE nobody already know the right from wrong now for this or that headphones in particular, hence i dont want to mess with the delicacy of the grill right now in assembling and desassembling it many times.

p.s. i put duro 30 1/8 inches on my HE400 i cannot imagine better...duro 30 is very malleable under pression and perhaps better for the HE400

IMPORTANT NOTE: i cannot insist enough on that : too much sorb or too big piece will DESTRUCT the sound...i made this mistake in the beginning... i cannot insist enough on that:worsening the sound is very easy...My 6 rules will help you to try and when you will got it right, the result will be unmistakable. Essentially it is the end result when you have a clarification on all the spectrum,with an organic very fluid sound,restitution of a more natural midrange with more depth,nearly out of the ears soundstage, a real 3-d sound,this would be the end result for the HE 400...good luck to all


P.S. description of the mod : i have four rectangular pieces (3/4 inches by 1 inches) at the bottom of the hoop... the spacing is visible on the photos... i had four other little pieces (each 2 set of 2 little squares pieces of approx 1/2 inches by 1/2 inches approx. distributed between the center of the hoop in the upper half of the cup... the height is very tight there with 1/8 inches thick pieces of sorb( if i had one i would have tried with 1/10 inches there ) .. it is important to cut all these pieces in 6 ,,, the sound is better more soundstage and very silky sound.... Hence i had now 8 pieces on each cup of the headphone in all cutted in six...Between the 2 groups of 6 pieces on each cup there is a void space of approx 2 inches 1/2 without pieces...

Conclusion
The naked metallic case of the HE400 product vibrations resonance that kill the sound... I had not listen with pure bliss to my he 400 really for next to 2 years because these vibrations plagued the sound... i changed 4 times of amplifier with some good results but nothing was great before i begin to investigate this sorb. mod. this thread of Edstrelow is a great discovery the most important one... the great crowd of headfiers listen now their headphone without knowing that they dont have access to their true potential... it is a pity... it is the reason i put my observation here...In reality the Sorbothane application is not a modification of the headphone but a true restitution of the headphone potential... Perhaps it will be better to name this sorb. restitution rather than modification, it is in the end not a physical structural modification of the original product but the cancelling of the negative effect of vibration... My method confirm Edstrelow discovery that the sorb. mod transform the Stax more than an upgrading amplification and i confirm that for the HE400, with the application rule i describe below...

I apologize for my bad English(it not my first language ) thanks for your kind interest

p.s. i had seen a video about anax mod for taming senn HD800... i am pretty certain than the application of Sorbothane there will do a more miraculous cure... the reason is simple the material used in the anax mod does not have the filtration capacity of a pieces of sorbothane squared or diagonalized... A material only per se cannot filtrate highs and bass , sorb cannot if not squared, hence the anax mod must cure the peculiar high frequencies problem of this headphone but cannot cure all his vibration problem..I dont have an HD800 to experiment with,only my 2 cent as i say i am only an amateur... Same probably for ALL headphones...

EVIDENTLY ALL HERE PRESENTED LIKE FACTS ARE ONLY MY HUMBLE OPINION AND EXPERIENCE, I CANNOT BE RESPONSIBLE if you do not apply my guideline for 2 reasons: with sorbothane very little variation with form, cuts,thickness, duro, made BIG differences , and secondly in audio all is matter in the end of personal taste and past experiences...thanks to all of you

IMPORTANT NOTE AND ADDITIONAL INFORMATION : after 2 months with the sorb mod. it seems that the gluing process is very slow on metal, and the glue adhrence take weeks, I now observe a spectacular more imaging capacity and 3 d presence ....Hence WAIT for the better to come if you put the sorb on metal cups...I was listening the he 400 for 2 days now after 2 weeks without listening to them and i observe that upgrade with the gluing bonding adherence with awe...

 

[chrismini]

Hello Richard. Remember me, Chris?

 

[richard51]

salutation Chris.... I hope all is right for you my best to you...

 

[skwoodwiva]

(Edit October 13, 2015 This thread has changed considerably since i started it with the intention of showing how the sound of Stax phones could be improved by using sorbothane on various portions of the earcups. Several other Headfiers have joined in to discuss the use of sorbothane and even some other materials to achieve these improvements on Stax and various other phones. This is all to the good in my opinion because it has gradually become evident that there is a problem of undamped mechanical resonance in many, if not all headphones. The more phones which are studied the more we will come to understand the nature of the underlying issues of mechanical resonance. It is clear that this is no longer simply an issue for Stax or even electrostatic phones.

My efforts and those of others to come up with damping strategies with Stax phones are found in the earlier posts. Whenever I have modified my methods, I have edited the posts for those phones, including the Stax Lambdas, SRX III pro, Sigma/pro, SR007 and SR003 so what is there should represent my latest take.

I am trying to get another thread started to explain this problem. It is taking me a while to get this together, although there are snippets of explanations scattered throughout this thread and the previous thread dealing with the SR007 )



I have been toying with a write-up of my efforts to damp the vibrations in the earcups of various Staxen by sorbothane, something I have been playing with for almost 1/1/2 years. I realized that it was going to take a long posting to cover the 007A, 003, SRX3 Pro, Sigma Pro, Sigma/404 , Lambda LNS and Lambda 404 and that I was just not going to get it done. That plus the fact that I am still experimenting and have by no means fully explored this phenomenon to my satisfaction. However, I am reasonably happy with what I have done with the Lambdas and as these are probably the most common Staxen I thought it would be worth reporting these first.

EDIT 5/28/15 - When I started this work I did not have much more to go on than that I had found that under some circumstances the application of sorbothane to the earcups or other parts of some headphones could make an almost remarkable change in their sound. Now I realize that as important as that may be, more significant is the fact that doing anything to the body of the phones could markedly change their sound. I now believe this means that there is a large amount of mechanical energy floating around most phones, which is insufficiently damped and which is messing up the sound of even the best phones. Even more remarkable is that this phenomenon has either not been observed before or been ignored by even the top headphone makers. I will develop this argument at a later time, although portions of it are scattered throughout this thread. I am keeping the current thread for discussions of what may be the more effective types of sorb mods for the various Stax phones I own.

I got started on this issue when I noticed that the arc assembly of the 007A appeared to impact the sound of these phones. http://www.head-fi.org/t/671314/stax-sr007-resonance-problems I will grant that the first reaction of anyone who looked at this posting was very likely What? It is odd to claim that the headband has an impact on sound. But that's what I heard. I put together a simple damping mechanism using sorbethane and a plastic clamp, played with it, liked what it did to the sound and left it alone for many months. (EDIT: so far I have only heard this on the 007, but cucera has recently reported damping the headband of the 4070, which looks like it has much the same kind of band arrangement as the 007, i.e it screws directly to the earcups. Other Stax headbands, have at least one other segment separating the headband from the earcups and that, I used to believe, makes a big difference. Now it is more evident that it is easy for vibrations to travel across most headbands. Companies including B&W and Audioquest are specifically working on this problem.

After a while it dawned on me that even though the arc assembly may have been vibrating during the playing of music, the real problem had to be where the vibrations were coming from, presumably the earcups themselves since that was where the energy originated. I.e. there was energy floating around the earcups which was making it to the 007A arc assembly because of the way the earcups were tightly screwed to the arcs. If so, was there a similar issue with other Stax headphones and how could you find out?

After an even greater time I started playing around first with a Sigma Pro by putting a strip of sorbethane across the bottom front of the earcups. It made the sound awful. The bass could only be described as flatulent i.e a bass fart. There may have been some increased clarity in the upper and mid frequencies but the awful bass squelched this experiment. However it did show that something was going on in the cups and I did eventually come up with a reasonable fix for the Sigmas. But I am still playing with it so I don't want to discuss it first.

The Lambdas were a lot easier. There is room on the baffle board that holds the transducer to attach strips of sorbethane around the drivers. I used self-stick sorbethane about 1/8 inch thick. (EDIT I am now using 1/4 inch 70 duro sorbothane, cut into small segments with no dimension longer than 3/4" to 1. I am also playing with 1/2 " sorb but this is very difficult to locate on many phones, but is even better. The 1/8 inch is good but the 1/4" is better, and the small segments appear better than the longer segments noted in the original pictures.You can buy this stuff on ebay for a few bucks and it comes in various thickness down to 1 mm, with or without self-stick. It took about 10 minutes to install this on the Lambda LNS and 404s and because it's out of sight you would never know it's there. It may add an ounce or so weight to each cup.




So what does it do to the sound? Makes it tighter, cleaner, gets rid of some fuzziness and brings out sonic detail including harmonics. It's hard to do a before and after comparison with the Lambdas because of the time it takes to install the sorbethane but I was able to do this with the Sigmas because with these the sorbethane was simply stuck to the outside of the cups ( after I got an arrangement that I thought sounded good) and could be just peeled off. With both Sigmas, upon ripping off the sorbothane suddenly there was a jump in sound level, in which an odd ambience suddenly appeared. It wasn't unpleasant but it probably wasn't music either. It adds a fair bit to the volume though and probably ends up masking the sound coming from the drivers. This, I think is resonance which is getting damped by the sorbothane resulting in a lower overall signal. With all of the Stax I have tried with sorbothane, I find I am turning up the volume more. (but enjoying what I hear more too)

So what have I got here? A possible tweak with Stax phones. It could work with others but I don't have anything else. I would be especially curious to know if dynamic phones are affected this way. And as I stated in the beginning, these are merely first efforts. There are obviously a lot of parameters to play around with such as the location of the damping material, how much to use, its thickness, how it is fastened (I am still working on clamps so that the pressure can be adjusted) and whether there might be other materials which could work better. Sorbothane also comes with different levels of stiffness (duro) so presumably this is a factor too.

EDIT
A number of people have been reluctant to open them up to put sorb inside. However there is little or no other place on the earcups to put any significant amount of sorbothane. On other phones, you can place it outside but the Lambdas have almost no solid surface to do this, except the baffle. The lambdas are not that hard to open. For a start you don't need to remove the earpads, such peel them back a bit and unscrew the corner screws.


The baffle may be somewhat stuck. Stax does not glue them as should be obvious from the use of 4 screws to hold the baffle in place. However the baffle can feel stuck, possibly because glue from the earpads gets in to the space. However, a bit of careful prying will get the baffle out.



Lift the baffle a few millimeters all around and then lift it up along with the section where the cord enters the earcup and voila you are ready to go.

I have plenty of insoles, shall I put one in the blender?

Water helps

 

[skwoodwiva]

Imitation is flattery!
Good thread

 

[skwoodwiva]

@edstrelow
Can you see how the heel pad, by just hugging the magnet, acts like one of those massive building weights opposing / absorbing back movement.

 

[Maxx134]

(it is possible to made the cut cleaner than mine with a razor blade..)


How to make a simple filtering space with many pieces of damping sorbothane : 6 RULES: 1 Many small pieces works better than more large one 2 too big mass of sorbothane does not work well , because too much is worse, (too much damping is a catastrophy, blutak mod for example is damping mod hence +sorb mod maybe too much damping simultaneous mod) and 3 the right thickness and duro...mine is 30 duro,1/8 inches for the metallic cup of the HE400, i had not try higher duro because i think the 30 duro work so well for me 4 and not more than 65% of the surface covered by sorbothane and probably around 50% or a little more is way better ....5 cut rule modulo 6 : with a razor blade or an exacto you cut a rectangular pieces in 6 little squares. ( it is not necessary to cut it before sticking it to the headphone, it was more easy for me to cut it after because i want them very close one another)I had originally stick 4 pieces of sorb at the bottom of the hoop, i cut now the four rectangular pieces of sorb in 6 pieces each, hence at one level i have 4 pieces of sorb, at another level i have divided these 4 pieces of sorb in 24 pieces, and i think that the mass of sorb act at one level as a 24 frequencies filtering mass, at another level act like an agglomerate 4 filtering frequencies mass of sorb... the principle is simple : divide the mass in cutting it in 6...

i am no engineer but the end result was extraordinary...clear sound across the board...that is my experience... The filtering of frequencies is not optimalized if the mass of damping sorb is too much big for the space damped or too homogeneous...In short i think the agglomerate of 48 located masses(6X8 on each cup) absorb better some higher vibration and the 4 little masses in the upper part of the cups and the 4 in the lower part of the cup act like 8 separate units and absorb better some other bass vibration... In short the GOLDEN RULE :cutting in 6 the damping mass of sorbothane transform it in a filtering space for various resonance. Effectively the form of any piece of sorbothane play a major role in vibration absorption.If for example the cuts were not totally completed and if the 6 little pieces are always partly linked together because the cutting was not absolutely complete the lack of clarity of the highs frequencies will be evident in a less detailed soundstage ...

Added 24oct: It seems that the filtering effect of the highs are better realized for me with this design cuts :



the highs are clearer and the bass untouched or less marked by these cuts, a rectangular piece of sorb cutted in 6 little squares.... i had translate all i had previously written in this post with my new experience (4 into 6 pieces) this is way better mod that clearly made an improvement of the definition of soundstage, if higher frequencies are more clearly defined, soundstage and localization of instruments are better , hence the filtering effects of dividing strip of sorb in 6 is an astounding improvement....

rule 6 : necessary to square all pieces of sorb,never sticking an integral piece of sorb without cutting in 6 or the sound will be more muffled; the filtering of the sound makes all frequencies more organic and will offer to you a more airy sound (Of my 8 pieces of sorb when 2 or 3 has been stick without being cutted in 6 the effect is immediately audible the sound was less airy less clear) . But i think, i had not try that, it is intuitive speculation, that the cut in diagonals will be better for the filtering effect : ( if someone try that let me know the results, i dont have leftover sorb to try )

i am no engineer but the end result was extraordinary...clear sound across the board ON MY 2 DIFFERENT headphones...that is my experience... The filtering of frequencies is not optimalized if the mass of damping sorb is much too big for the space damped or too homogeneous, that is the fundamental rule of rules...In short i think the agglomerate of 6 little squares act like one located mass and absorb better some bass vibration and the 6 separate little masses in each of the 4 upper and 4 lower rectangular pieces absorb better some other higher vibration... In short the GOLDEN RULE cutting in 6 the damping mass of sorbothane transform it in a filtering space for resonance. Effectively the form of any piece of sorbothane play a major role in vibration absorption (the sorbothane site affirmed that if i remember). I am no scientist, it is only my explanation...

It is an experiment in relation with the basic material of your headphone, plastic or metallic, the densities of your headphones, etc,and you must explore by Yourself and experiment, and READ the thread of Edstrelow to know the basic...People dont read these days... i put the sorb. outside BECAUSE nobody already know the right from wrong now for this or that headphones in particular, hence i dont want to mess with the delicacy of the grill right now in assembling and desassembling it many times.

p.s. i put duro 30 1/8 inches on my HE400 i cannot imagine better...duro 30 is very malleable under pression and perhaps better for the HE400

IMPORTANT NOTE: i cannot insist enough on that : too much sorb or too big piece will DESTRUCT the sound...i made this mistake in the beginning... i cannot insist enough on that:worsening the sound is very easy...My 6 rules will help you to try and when you will got it right, the result will be unmistakable. Essentially it is the end result when you have a clarification on all the spectrum,with an organic very fluid sound,restitution of a more natural midrange with more depth,nearly out of the ears soundstage, a real 3-d sound,this would be the end result for the HE 400...good luck to all


P.S. description of the mod : i have four rectangular pieces (3/4 inches by 1 inches) at the bottom of the hoop... the spacing is visible on the photos... i had four other little pieces (each 2 set of 2 little squares pieces of approx 1/2 inches by 1/2 inches approx. distributed between the center of the hoop in the upper half of the cup... the height is very tight there with 1/8 inches thick pieces of sorb( if i had one i would have tried with 1/10 inches there ) .. it is important to cut all these pieces in 6 ,,, the sound is better more soundstage and very silky sound.... Hence i had now 8 pieces on each cup of the headphone in all cutted in six...Between the 2 groups of 6 pieces on each cup there is a void space of approx 2 inches 1/2 without pieces...

Conclusion
The naked metallic case of the HE400 product vibrations resonance that kill the sound... I had not listen with pure bliss to my he 400 really for next to 2 years because these vibrations plagued the sound... i changed 4 times of amplifier with some good results but nothing was great before i begin to investigate this sorb. mod. this thread of Edstrelow is a great discovery the most important one... the great crowd of headfiers listen now their headphone without knowing that they dont have access to their true potential... it is a pity... it is the reason i put my observation here...In reality the Sorbothane application is not a modification of the headphone but a true restitution of the headphone potential... Perhaps it will be better to name this sorb. restitution rather than modification, it is in the end not a physical structural modification of the original product but the cancelling of the negative effect of vibration... My method confirm Edstrelow discovery that the sorb. mod transform the Stax more than an upgrading amplification and i confirm that for the HE400, with the application rule i describe below...

I apologize for my bad English(it not my first language ) thanks for your kind interest

p.s. i had seen a video about anax mod for taming senn HD800... i am pretty certain than the application of Sorbothane there will do a more miraculous cure... the reason is simple the material used in the anax mod does not have the filtration capacity of a pieces of sorbothane squared or diagonalized... A material only per se cannot filtrate highs and bass , sorb cannot if not squared, hence the anax mod must cure the peculiar high frequencies problem of this headphone but cannot cure all his vibration problem..I dont have an HD800 to experiment with,only my 2 cent as i say i am only an amateur... Same probably for ALL headphones...

EVIDENTLY ALL HERE PRESENTED LIKE FACTS ARE ONLY MY HUMBLE OPINION AND EXPERIENCE, I CANNOT BE RESPONSIBLE if you do not apply my guideline for 2 reasons: with sorbothane very little variation with form, cuts,thickness, duro, made BIG differences , and secondly in audio all is matter in the end of personal taste and past experiences...thanks to all of you

IMPORTANT NOTE AND ADDITIONAL INFORMATION : after 2 months with the sorb mod. it seems that the gluing process is very slow on metal, and the glue adhrence take weeks, I now observe a spectacular more imaging capacity and 3 d presence ....Hence WAIT for the better to come if you put the sorb on metal cups...I was listening the he 400 for 2 days now after 2 weeks without listening to them and i observe that upgrade with the gluing bonding adherence with awe...

I have seen it all now.
Exterior modding actually funny but in a cool way.

I don't deny your results though.

I have used sorbothane inside cups over dynamic drivers with some success with bass,

but for resonance control, I would rather dampen than absorb,
so I like dynamat type material,
yet they add more weight than sorbothane.

Sorbothane is a tricky material for me to get most out of.
I still use sorbothane,
but in tension, not in an "at rest" state.

In my experience ,their best performance are done in either a "slight comprehension", or a "slight expansion" state.

I never posted about it before but its cool the ways it has been chosen to be used here.
So hat's off to you guys.

 

[richard51]

I have seen it all now.
Exterior modding actually funny but in a cool way.

I don't deny your results though.

I have used sorbothane inside cups over dynamic drivers with some success with bass,

but for resonance control, I would rather dampen than absorb,
so I like dynamat type material,
yet they add more weight than sorbothane.

Sorbothane is a tricky material for me to get most out of.
I still use sorbothane,
but in tension, not in an "at rest" state.

In my experience ,their best performance are done in either a "slight comprehension", or a "slight expansion" state.

I never posted about it before but its cool the ways it has been chosen to be used here.
So hat's off to you guys.

I use the sorbothane now mostly inside the He 400 .... and some between the headband to isolate the 2 cups.... I dont put in on the exterior cups anymore.... More practical to put it inside .... On My AKG 340 though I mostly put the sorb at the exterior around the cups compressed with elastic band because for this can it is more easy... Great results....

 

[edstrelow]

Maxx134 Looks like the outside of my Stax SRX 3 which I covered the same way. I cannot stress too much that covering the pieces with 4 layers of electrical tape magnifies the damping effects. hat is the principle of constrained damping.

 

[edstrelow]

I have not been too active of late, essentially because I have achieved my goal of getting effective damping of my headphones and loudspeakers and I have thus been doing less experimenting. Now it is just a matter of waiting for the rest of the audio world to catch up. Here is my headphone line-up, Stax SR007, Stax Lambda (404 and LNS) and Sigma (Pro and 404.)

You can see a lot of damping on the outside of these phones, especially on the headbands. It came as a surprise to me that placing damping material on the bands would be effective, but as we know, Sennheiser figured this out years ago and is doing it now on its best dynamic phones and very likely to its stats as well.

I have converted fully over to 70 duro sorbothane. I prefer to use the thickest sorb I can find, generally maxing out at 1/2 inch. The 3M self-stick is effective but not available on 1/2 inch sorb for which I have been using very expensive Lord 7650 glue, which came recommended by Sorbothane. The gluing matters a lot. You can hear the difference in sound as the glue cures (for 7650 that is a week or more, although it sticks well after an hour.) In fact even the tape cures over several hours.

You will also notice that I am using fairly small pieces.\ of sorb. This has been one of the more interesting findings in this forum and several others agree that you get the best results if you use small pieces, eg. an inch or less in dimension. This was counter intuitive to me and why it works, I still don't understand.

On top of the sorbothane I have also been adding 4 layers of electrical tape on the top (i.e. unglued side), thus turning the damping process into "constrained damping." I swear this doubles the effect of sorb. Possibly this article helps. https://en.wikipedia.org/wiki/Constrained-layer_damping

I have also been sticking sorbothane mounted as near as possible to the drivers.

Irrespective of Sennheiser's choice, I see no reason to let vibrations loose in the system and it seems a better practice to dampen them as close to the drivers as possible. This somewhat blurry shot shows small 1/4 strips, not yet covered with 4 layers of tape on the Sigma set-up. The Lambdas are treated similarly, while in the SR007, the sorbothane is stuck to a metal plate inside the earcup.

Finally, I have been working on my speakers. This shows placements around my Polk SDA 1's. I have tried various thickness and the like over the last few years. I believe all of these are 70 duro, although some are no the 1/2 inch sorb that I recommend. Also some have only 2 layers of constraining tape, 4 is significantly better than 2.

What does one gain by such damping? A huge improvement in sound quality. I have been to a fair number of audio shows and have heard nothing of this order of magnitude since I was exposed to me first electrostatics, many years ago. And of course damped stats gain hugely as well. The gains of damping on sound quality are in several dimensions:

1) Dynamics, the attack and detail are much enhanced. I recall when I first realized with my early experiments that I was involuntarily tapping my feet to the rhythm. The treble detail, such as triangle, attack on strings, tremolo is much enhanced.

2) tonal accuracy, you get more overtones and instruments and voices sound more real.

3) Spatial imaging on headphones is much enhanced. Instruments and voices are localized better in space and the spatial field becomes wider. This is presumably because of the damping of opposite channel signals across the headband (i.e. crossfeed.) Basically, if you mix left and right channel signals, you will get less stereo. Sorbing reverses that trend. If you go back some pages you will see where Mitchell actually measured the mechanical crossfeed from one earcup to another, i.e. he could detect and measure the left channel in the right earcup or vv.

4) Removing garbage sound. Volume goes down in my systems after sorbing. I generally will turn up my Stax headphone amps about one notch after damping of the phone. This is what I expect if the sorbothane is getting rid of some of the signal. Once early on, I quickly removed sorb which had been stuck on the front of my Sigmas, while listening to them. The sound level suddenly jumped about one amplifier notch. But what you heard was a sort of weird ambience added to the signal. That at least is how my brain interpreted it. That I suspect is the sound of the buzzing in the system caused by the mechanical vibrations.

What are the basic physics here? At the outset we have Newton's rule that for every action there is an equal and opposite reaction. That's what is pumping mechanical energy into the earcups and speaker cabinets. However, energy does not just die, it has to be converted to some other form of energy. Sorbothane claims it converts mechanical energy to heat, thus getting rid of it that way. If you don't get rid of this energy it either causes the earcups/speaker boxes to vibrate, or what I think is more likely, feeds energy back into the drivers, thus messing up the driver's operation and rubbish sound is being added to the music. Presumably this rubbish energy still dies fairly quickly, i.e. in the milleseconds range otherwise you would be hearing sound on your phones/speakers after the music stopped. Sorbothane damping merely accelerates the process.

I am very happy where I am in this exercise. I have great sound probably in the top 1% of high fi systems and at very little cost. I just laugh as I see the rubbish being talked about super costly systems, knowing that whatever the merits of such systems they are almost all suffer the major distortion that I am eliminating in mine and that they are not. And yet I suspect I have not got the absolutely best results even now. I have been struck that the sound just keeps getting better the more damping I add. I am guessing that I haven't got the full benefit especially on low frequencies, where according to Sorbothane, thicker sorb, eg. 1 inch or more works best. It is difficult to add 1 in sorb to most headphones, except on the headband. I suspect I may add some to the back of my speakers to see.

 

[Maxx134]

On top of the sorbothane I have also been adding 4 layers of electrical tape on the top (i.e. unglued side), thus turning the damping process into "constrained damping." I swear this doubles the effect of sorb. Possibly this article helps. https://en.wikipedia.org/wiki/Constrained-layer_damping

I do not dissmiss your methodology or results at all, but I like to try clarify some points.

Sorbothane was designed to work under pressure, or tension.
I see most usage here without pressure or tenion, which is good to know it still works.

I thinking your taping was good for adding pressure to the sorbothane.


But your link is a bit different.
Constrained damping works by use of different density materials, like what Dynamat does.

Both work great and you have shown very interesting results in the usage of sobothane methods.
Thanks for showing this.

I used sorbothane as well with success.
It deserves to be suggested for its benifits.

 

[richard51]

My testimony is the same ...A system without vibration does not exist....

 

[edstrelow]

I do not dissmiss your methodology or results at all, but I like to try clarify some points.

Sorbothane was designed to work under pressure, or tension.
I see most usage here without pressure or tenion, which is good to know it still works.

I thinking your taping was good for adding pressure to the sorbothane.


But your link is a bit different.
Constrained damping works by use of different density materials, like what Dynamat does.

Both work great and you have shown very interesting results in the usage of sobothane methods.
Thanks for showing this.

I used sorbothane as well with success.
It deserves to be suggested for its benifits.

Re: sorbothane under pressure. I have been on this problem for a few years and there is even one earlier thread just dealing with the Stax SR007. I have talked a couple of times with technical reps as Sorbothane who gave me some pointers but had little to specifically discuss about speakers and headphones. Often it is used in industrial applications, as footers for equipment but it has to be carefully tailored to the weight of the object and the frequencies needed to be damped. Vibration damping is a big deal to mechanical engineers and I have discussed what I have been doing with a half a dozen, and they they all seemed to understand and agree with the approach. I do recall talking to one of the Schitt designers who acknowledged the use of sorb to dampen circuits in some of their equipment. To my mind this problem is one of the last frontiers of audio.

My first efforts used clamps on the sorb but over time I found I used little pressure to get the best sound. Then I started just sticking the sorb on using the self-stick or other glues and it seemed that I was still getting good results and I stopped playing with clamps. Still later I used electrical tape to hold some in place on headbands, by wrapping the sorb to the band. I liked that even more, and finally realized that simply covering the back with tape gave as good result as wrapping. I got the term "constrained" damping from Mitchell who did the measurements of mechanical crosstalk on headphones. That does not imply pressure, just a wall of sorts on the back of the material.

There's a lot of basic physical measurement needed here to understand the phenomenon and to determine the best methods of damping. I would like to see measurements of the amount of vibration in earcups and speaker boxes and then a concerted effort to dampen it to non-existence. Then I want to hear what non-vibrating speakers and phones sound like.