[richard51]

  Are you still using the sorb mod with the bigger amp?

For sure.... Its impossible to go back.... The he 400 is better , way better with the sorb mod.... How could i go back?  thanks to you.... But if you had planars headphone, the receiver transform totally the headphone....I dont listen to my headphone amp now.... sorb mod + hitachi receiver =  top of the line planars 

headphone

 

[edstrelow]

 
For sure.... Its impossible to go back.... The he 400 is better , way better with the sorb mod.... How could i go back?  thanks to you.... But if you had planars headphone, the receiver transform totally the headphone....I dont listen to my headphone amp now.... sorb mod + hitachi receiver =  top of the line planars 

headphone

It sounds like the overall result of using the bigger amp on sorbed phones is very good.  My question, which you may not be able to answer is would the big amp be as impressive on on phones with no sorb damping?
 
I have a somewhat similar issue with Stax phones.  There are several high end amps for these phones selling $5,000-$6,000.00. I have heard some of these at 2 Canjams and they were clearly  better with my unmodified phones  than my $1,000 amp..  But I also think the sorbed phones sound better on my $1,000 amp than the unsorbed ones did on those expensive amps.
 
However,  I have yet to listen to sorbed phones any of the $5000 amps,  except for one and on that one (no name mentioned) I didn't hear enough benefiton the sorbed phone to justify that kind of expense. Of course I was also listening to a different transport and DAC with the expensive amp and I suspected that  these  were working against the quality of the amp.

 

[richard51]

  It sounds like the overall result of using the bigger amp on sorbed phones is very good.  My question, which you may not be able to answer is would the big amp be as impressive on on phones with no sorb damping?
 
I have a somewhat similar issue with Stax phones.  There are several high end amps for these phones selling $5,000-$6,000.00. I have heard some of these at 2 Canjams and they were clearly  better with my unmodified phones  than my $1,000 amp..  But I also think the sorbed phones sound better on my $1,000 amp than the unsorbed ones did on those expensive amps.
 
However,  I have yet to listen to sorbed phones any of the $5000 amps,  except for one and on that one (no name metioned) I didn't hear enough benefits to justify that kind of expense. Of course I was also listening to a different transport and DAC with the expensive amp and I suspected that  these  were working against the quality of the amp.

Its completely 2 different things.... the Hitachi receiver offer to my he 400 what they needed....power....there is no comparison between  headphone amp (i have a very good one the Ember ) and the Hitachi....Planars needed raw power its simple ...Before trying i was sceptic...the sorb mod affected all headphone  because that dissipate vibration... With sorb mod any headphone (he 400 included) is no more the same headphone ... With the receiver the he 400 is no more under-amped... i know now that planars headphone are, more often than not, with ordinary headphone amp under amped...What is better ? sorb mod or receiver mod? the TWO are necessary if you had planar headphone...they dont affect in the same manner.... The sorb mod refines all the tonal spectrum, the receiver amplify all that to a new level.... i am in sonic bliss now.... and not in hurry to upgrade...the sound is REALISTIC , 3-d, with a real textured timbre, an oceanic bass, a fluid higher frequencies and more mids, my he 400 are no more v-shape more u-shape...thanks to sorb mod +hitachi 

 
 
p.s. my stax without any mod  has a more refined sound than my he 400 without any mod...but  without modification i prefer already  the more incarnated sound less surreal sound of my he 400... with sorb mod i prefer it more.... and way more with the Hitachi.... Stax are other animals than planars... They are probably more sensitive to the sorb mod than planars hence the sorb mod transform them more than an upgraded amp... Planars need to be more incarnated in the 3-d world, the sorb mod give them a better refinement all across the spectrum but the impact of a powered speakers amp on them is spectacular...i will not go without  the sorb mod, no way.... I will not go without strong amplification no way with the he 400... sorb mod =refinement, reequilibrium... power amplification= more realistic 3-d sound and soundstage
 
REVISED OPINION : the sorb mod rightly applied (check my 6 rules below ) has more impact on the sound of my HE400 than any of my amp... I must say that Edstrelow was right when he speaks of that with his stax... same here with Hifiman headphone ... Thanks Edstrelow

 

[nick n]

richard51:
 
The Soviet stuff is all over the map according to which model, a couple have a T50/30 -like driver, one is a giant rectangular thing and another couple are 55 and 60mm circular PMB type ( but not PMB ). Then another yet is rare and very unique circular driver.
I used a TDS-16 Smela model 55mm for that mod, but it sounds quite different due to specific mod materials used and shell cavity and mini damping chamber directly on the driver rear I did.
 Hard to say how the HE models will compare due to size differences and other factors.
This one is unique anyhow even against it's stock relative.
 
And the Dynamic thing was a clone of another I have or so I thought, but it was good in it's own right so I decided to test it out due to simple and cheaper materials construction.
Not worth mentioning it since it is only 1 of 2 I have ever seen.
 
I went in to see what effects I could get out of my Ultrasone Pro2500 a few minutes ago.
I tried 10 x 1cm squares on each side arranged around the outer baffle perimeter equally.
It killed the sound!
I reduced to 6 = a bit better.
I reduced to 3 and here it is back much closer to it's full glory again. I might reduce to 2 per baffle on either side of the driver opening at the bottom section.
Looking up the kees mod for Ultrasone ( Pro900 actually but similar baffle setup ) he used only a single circular damper and some things inside. O course not Sorbothane either which is why I wanted to try this version.
 
I don't get that nagging feeling that it sounds "slightly held back or slightly dead" right now.
 
So with 3 x 1cm squares per side = Bass is faster and bolder, and highs seem to have a bit more clarity and it seems easier to peer into the layering of everything.
 
I will update this when or if I try reducing it to just the 2 on either side of the driver openings.
 
Thought I'd post this because I went for bust and it turned out to not have the results I was expecting. Less was "more" in this particular case.
And this might happen with others I'd be curious to hear of similar results, though this does seem to be a limited crew playing around here.
 
Was not expecting that but I am hearing the effects here now.
Will it be tweakable down to 2 per side and stay improved?
Only time and a trial will tell.
But I will live with this for a bit. It's easy to narrow results down close to a bullseye but when you get this close it is best to sit with something for a while and learn it IMHO.
 
EDIT
 
Using 2 x 1cm squares brought it too close to stock sound =3 is the magic noticeable  transition point. Of course these baffles are only screwed in at 4 points and metal so that will explain why they are so sensitive to such a minor amount.
Would expect other builds to need the increased amounts.

 

[Hutnicks]

Question. Does anyone know of a liquid sorbothane that can be poured and let to set?

 

[nick n]

Only tried the liquid version of Plasti-dip myself, but that is of a different consistency entirely compared to this 30D.
Sorry for the no-help
Will look around
 
One possibility is a pourable Silicione material. http://www.mgchemicals.com/products/rtv-silicones/potting-compounds/rtv615/
When I get to trying the Permatex polyurethane on the car seals I will gunk a buit into a mold and see how it compares after it dries.
I have a sample of it on a paper no idea where it is. I t was more forgiving than Plasti-dip that's for sure.
 
I wonder how viscoelastic gels are poured and how to source those?
 
Wow visiting the MG Chemicals link under the technical data section, then under the Cured properties link  is a blue link with the following:
 
Durometer Hardness Comparison Chart ( WOW gives direct equivalent to Sorbothane measurement "D" ratings ) at room temperature (25°C)
 
it gives that pourable silicone linked a Durometer value of 44 which is a nice range within the Sorbothane options
 
Cured Properties -
MECHANICAL Hardness, Shore A Durometer 44
Tensile Strength, kg/cm² (psi)65 (920)
Elongation %120
Shrinkage, %0.2
Refractive Index 1.406 ( wonder how this compares )
 
I'll see if the local industrial electronics wholesaler here can get me a litre plus the 1:10 curing agent. They have a ton of MG stuff as it is.
 

 

[edstrelow]

  richard51:
 
 
I went in to see what effects I could get out of my Ultrasone Pro2500 a few minutes ago.
I tried 10 x 1cm squares on each side arranged around the outer baffle perimeter equally.
It killed the sound!
I reduced to 6 = a bit better.
I reduced to 3 and here it is back much closer to it's full glory again. I might reduce to 2 per baffle on either side of the driver opening at the bottom section.
Looking up the kees mod for Ultrasone ( Pro900 actually but similar baffle setup ) he used only a single circular damper and some things inside. O course not Sorbothane either which is why I wanted to try this version.
 
I

Glad you found a sweet spot however I am curious about how much attenuation you got when you used 10 squares.  The generally find that sorbing a phone reduces the volume maybe 5-10 dB, maybe one notch on the volume control of an amp, which I put down to the loss of the reduction of vibrations in the earcups.  You seem to be talking about a whole different amount of reduction almost as if the driver was switched off.  Possibly something else in the way of a mechanical fault was occuring.
 

  Question. Does anyone know of a liquid sorbothane that can be poured and let to set?

 
 

  At this point then, it might be a good idea to consider how Dynamat (buytl rubber) and Sorbathane are being used to do the same thing (provide damping in an under damped environment). I honestly don't think that "circle v. square" matters in this case, because the stuff isn't bearing a load (the "coupling" between speaker / ground is not an issue - we are just tacking it into our ear cups the same way we'd take dynamat to our car doors). Sounds like we should use small circles IF we are asking it to de-couple a something from a surface subject to vibrations.
 
In terms of choosing a density, that is an interesting point. But I'm not really sure what frequencies are impacted? We are still on the assumption that it is 50 hz on up. I am persuaded that the mass is doing something (changing the resonance frequency), and the material is also "capturing" some of the energy of reflected waves. It might therefore be interesting to apply it to the front wave, and then see if its done something horrible (like jack up bass reponse and literally kill treble e.g. overdamped somehow). I figure density / mass is important, but I assume that a softer duro would actually be more absorptive, not reflective. Otherwise, why would cotton batting work? It is not dense at all, but dampens the back wave.

Among the many things that need to be investigated in regard to damping is what materials damp what aspect of earcup vibration. I use sorbothane because it has been used for a long time for damping various items of equipment, although as best I can tell it was not previously used on headphones.  I am sure other materials will do something.  One guy I met at Canjam in Orange County showed me his dynamic phone which he said used some sort of soft copper inside to dampen them.  They sounded pretty good too. 

 

[BeatsWork]

  One guy I met at Canjam in Orange County showed me his dynamic phone which he said used some sort of soft copper inside to dampen them.  They sounded pretty good too. 

 
Copper oxidizes easily on it's own + Perspiration + other metals:  I'd be worried about galvanic corrosion

 

[edstrelow]

   
Copper oxidizes easily on it's own + Perspiration + other metals:  I'd be worried about galvanic corrosion

I didn't get a chance to look  inside to see if he had taken steps to protect it.  I raise this example just to show that there may be other ways to solve this problem. I offered to add some sorbothane to his phones to see if that would further improve the sound but they had wooden covers and he didn't want to possibly damage them with the self-stick on the sorb. 

 

[nick n]

  Glad you found a sweet spot however I am curious about how much attenuation you got when you used 10 squares.  The generally find that sorbing a phone reduces the volume maybe 5-109 dB, maybe one notch on the volume control of an amp, which I put down to the loss of the reduction of vibrations in the earcups.  You seem to be talking about a whole different amount of reduction almost as if the driver was switched off.  Possibly something else in the way of a mechanical fault was occuring.

Is that a typo? Do you mean 5-10dB?
 
Sorry that was a very poor descriptor on my part.
What I mean to say is that it imparted an overall dullness and lifelessness to the sound regardless of volume levels.
I do think the particular construction of that series of Ultrasones is the culprit there in that the drivers are bonded ( with holes exposing only half the driver ) onto the metal baffle plate, and that baffle plate is only attached by 4 tiny screws at 4 points.
I think in this case it relies on that plate and is tuned to this exact arrangement.
Very strange yes it is, since this is contrary to the other dynamics I have tried it on so far.
I would have thought otherwise had I not tried it firsthand.
Suppose at some point I can retry that again.
 
Have some more things to try it on as more 1/10 30D arrived and the list is long.
 
BTW some more favourable results posted tonight that seem to be in line with what people are finding.
This initial picture and initial brief impressions 3 posts down.
http://www.head-fi.org/t/658673/yamaha-hph-mt220-thread-merged/2250#post_11973031

 

[edstrelow]

  Is that a typo? Do you mean 5-10dB?
 
Sorry that was a very poor descriptor on my part.
What I mean to say is that it imparted an overall dullness and lifelessness to the sound regardless of volume levels.
I do think the particular construction of that series of Ultrasones is the culprit there in that the drivers are bonded ( with holes exposing only half the driver ) onto the metal baffle plate, and that baffle plate is only attached by 4 tiny screws at 4 points.
I think in this case it relies on that plate and is tuned to this exact arrangement.
Very strange yes it is, since this is contrary to the other dynamics I have tried it on so far.
I would have thought otherwise had I not tried it firsthand.
Suppose at some point I can retry that again.
 
Have some more things to try it on as more 1/10 30D arrived and the list is long.
 
BTW some more favourable results posted tonight that seem to be in line with what people are finding.
This initial picture and initial brief impressions 3 posts down.
http://www.head-fi.org/t/658673/yamaha-hph-mt220-thread-merged/2250#post_11973031

I am glad to see discussions of sorb and other damping issues spreading to other threads. Yes that was indeed a typo, I expect to hear 5-10 dB reductions with damping.
 
As regards dullness, I find that sometimes loose sorb, i.e. sorb that is not sticking properly sometimes gives odd results like dullness and bass boominess. No idea why, just that I have noticed it a few times. Part of the many mysteries of mechanical damping. 
On a related matter, before using sorb to dampen headphones, I used various commercially available sorb pucks under cd players, turntables, amps and the like. There appeared to be some benefits although the results were not overwhelming. Some puck makers note that you have to match puck size to weight, something not easily done.  I am trying small self-stick sorb squares on equipment and think I am getting better results than with pucks. If you have some sorb left over you might want to experiment here.

 

[nick n]

Unsure how many more "proof of concept" trials are needed here since it all seems excellent.
I will continue to post new things simply to bump this thread.
Once again thanks for starting this and bringing this product to our attention.
 
 On to the next project here.
Today is a vintage Audio Technica Electret, the AT-706.
Running off it's proper adaptor unit that can provide either 5 or 10 volts with the flick of a toggle.
 
In stock form these have a low end advantage over the Stax electrets since these have a factory integrated yellow biscuit material ( glasswool ) under the rear driver housing struts, as well as a massive puck of the same in the cups.
Stax does not have the integrated damping in the drivers ( same drivers ) or as thick of a rear puck, more like a thin disc in the back against the outer mesh.
 
I installed rectangular segments of 1/10 in 30D ( all will be the same Sorbothane in my mods ) all along the entire outer raised edge of the drivers between mounting posts, and 6 small squares on the inner walls of each of the thin aluminum cups.
 Upon checking the first side I did immediately notice a lower volume, in line with what edstrelow mentioned above , perhaps around 5 or 6 dB on the "Sorbed" side.
 
 Contrasts noticed in treated side
 

1. volume drop ~5-6 ish dB
2. much more clarity =clarity extends through into the improved depth of sound. Stock form is still very clear but it seemed to have a slight fuzz or haze which would otherwise not have been detectable except in direct A/B comparison!
3. more bulk
4. bolder low end is more extended in comparison

So overall a definite, concrete, noticeable improvement.
 
Impressive
 
A pic is always nice. Same as my 705 below but different colour scheme. No pics of internal mod that would be boring and it's hard to capture in this set.

 

[nmatheis]

I had the pm-3 for about 2-3 weeks. I liked how smooth it is from top to bottom. It's really well balanced. The isolation is great and the clamp is about neutral. Not too tight for a portable.

But I sold it after I sorbed my mt220. Why? Because the pm-3 felt too compact. It was a wall of sound and I felt it didn't breathe well. If you like that feel, then you'll like the pm-3. Even my iems don't feel so compact. It has to be the most compact sound headphones I've ever heard.

I feel the same way about PM-3. The felt quite cramped physically and audibly and got hot pretty fast due to the small closed cups.

Anyway, I'm joining the sorb-mod crowd. Mine'll be in Tuesday, and I'll be putting it into my HE400. I'll report in. Thanks for the help getting going with this!

 

[nick n]

Excellent!
Please post up.
 I just did another vintage Fostex ortho tonight and the bass goes lower, is bolder, and all sorts of details are exposed vs before.
Took it for a long walk and yes it has changed.
 
Now on to see what I can add to the Yamaha HP-1 mod. Yes HP-50 and HP-1 orthos are done.
 
If I get the guts to try to take off the pads on the PM3 I will add some Twaron Angel Hair ( will take care of the more closed sound ) and Sorbothane, but the risk of breaking baffle pad tabs is pretty scary since the whole set with the matching drivers will need to be warrantied as I understand it.
Might do it and throw caution to the wind.

 

[richard51]

i had some news on the Frontline of Sorbothane mod... I take off 4 or the 12 patches i had put on the HE 400 (duro 30 1/8inches) and put them on the exterior faceplate of the cups of my FOSTEX TH7-B... Wow the sound is better in the mids BUT the sound of the He 400 with only 8 patches on the exterior edge of the cups was way better, in the highs and mids frequencies...The lesson to be learned is : Not to much sorbothane... very important