[soren_brix]

  ...So what does it do to the sound? Makes it tighter, cleaner, gets rid of some fuzziness and brings out sonic detail including harmonics. (first post)
 
... my first impression was of a reduction in harshness, greater separation of instruments and voices, better dynamics and a wider spatial field.    The bass is good, probably a bit better than before, but I wish it were a bit drier.  For my first listening,  I put on  the first recording of Lucia di Lammermoor by the great Australian soprano, Joan Sutherland, and was blown away by how good she sounded when she was young.... (later posting)
 
I have mounted 3M200MP on the vertical plate only, and can report similar impression. Although "greater separation of instruments and voices, better dynamics" this seems to be what I notice the most, greater separation and way better dynamics ...
Will let this settle for some days before doing some more, but definately worth a try.
 
 

 

[edstrelow]

I have mounted 3M200MP on the vertical plate only, and can report similar impression. Although "greater separation of instruments and voices, better dynamics" this seems to be what I notice the most, greater separation and way better dynamics ...
Will let this settle for some days before doing some more, but definately worth a try.
 
 

 

Good to hear this. The sound may change over time as the sorbothane bond cures although some of this could be getting  used to the new sound.

 

[soren_brix]

Tried the same damping on a pair of 202 much similar to what Edstrelow did to his 404's.
Damping the baffle only.
After some listning I recognised the better clarity. The sound is more tight and clean.
Tried to damp my 404 using sorbothane around the driver itself, rather than on the baffle. (the green area on the pic shown earlier, although going around the hole driver except for the area with the terminals). The result sounds much similar to the result from damping the baffle of the 202.
The much spoken etch that the 404 has almost disappeared.
As far as my experience the damping reduce the coloration and results in a cleaner sound with greater separation
Based on these findings and from Edstrelows reports, it seeems that the damping works best when applied to the source of vibrations or very close to, and can make things even worse if placed far from the source of vibration, although it seems to work damping the chamber of the 4070 also.
As far as I remember Spritzer made a few comments about the lack of glueing of the 404 driver itself using adhesive instead and that caused a great deal of coloration.I cannot see whether my 404 drivers are glued or pressed together using some adhesive.I guess using the sorbothane directly on the driver rather than at some distance must be the right way.

 

[edstrelow]

Good that you like what the sorbothane addition does to the sound.  I don't think I have been exaggerating these effects.  Anyone who wants the best sound from their phones, irrespective of make, should try this stuff.
 
 I think the best location to add this stuff is as close to the drivers as you can get. However I have noticed that merely adding a small piece on the oustide of an earcup (as in the SRX III) can give you some improvement too although I think the ideal would be close to the drivers.or as you note, on the drivers.
 
I can just vaguely visualize drivers made where the sorbothane is on the drivers as part of the design.
 
Re the 404 drivers:  I have also found mine to come loose, in fact I had to put them back where they were supposed to be before I could add the sorbothane.  Now the sorb helps to keep them in place.
 
I don't know how many Stax phones have this "wandering driver" problem .  My LNS and my old Nova (since sold) didn't do this.

 

[soren_brix]

to my knowledge the driver should be glue to the baffle and not able to move at all.
If your driver is loose I suggest you glue it to the baffle or fixate it using adhesive as Spritzer tend to.

The sigmas i have converted to sigma/404 has the driver glued to the baffle.

 

[edstrelow]

to my knowledge the driver should be glue to the baffle and not able to move at all.
If your driver is loose I suggest you glue it to the baffle or fixate it using adhesive as Spritzer tend to.

The sigmas i have converted to sigma/404 has the driver glued to the baffle.

I understand what you are saying.  The 404 drivers are firmly in place right now but they move over time because the glue seems to have become soft over the years.  If the problem continues I will have to try some other glue but I am more wary than Spritzer about messing with the drivers.

 

[edstrelow]

  Tried the same damping on a pair of 202 much similar to what Edstrelow did to his 404's.
Damping the baffle only.
After some listning I recognised the better clarity. The sound is more tight and clean.
Tried to damp my 404 using sorbothane around the driver itself, rather than on the baffle. (the green area on the pic shown earlier, although going around the hole driver except for the area with the terminals). The result sounds much similar to the result from damping the baffle of the 202.
The much spoken etch that the 404 has almost disappeared.
As far as my experience the damping reduce the coloration and results in a cleaner sound with greater separation
Based on these findings and from Edstrelows reports, it seeems that the damping works best when applied to the source of vibrations or very close to, and can make things even worse if placed far from the source of vibration, although it seems to work damping the chamber of the 4070 also.
As far as I remember Spritzer made a few comments about the lack of glueing of the 404 driver itself using adhesive instead and that caused a great deal of coloration.I cannot see whether my 404 drivers are glued or pressed together using some adhesive.I guess using the sorbothane directly on the driver rather than at some distance must be the right way.

 
I don't have an open Lambda and I can't recall how the dust cover is set up. As I understand it you have attached the sorbothane to the edge of the 404 driver, i.e. the what you show as green in your previous picture of the Sigma (which uses the same driver as the Lamda).  Can it be placed on the top of the driver, i.e. what you mark as blue without interfering with the dust cover?
 
 

 

[soren_brix]

  I understand what you are saying.  The 404 drivers are firmly in place right now but they move over time because the glue seems to have become soft over the years.  If the problem continues I will have to try some other glue but I am more wary than Spritzer about messing with the drivers.

As far as I have experienced the driver sandwich is rather stable and rigid. I have experienced some lambda drivers litteraly falling apart when cutting them free from the baffle; the glue has simply lost its gluing ability due to aging I guess. Those were drivers back from very early 80's.
Cutting the drivers free from the baffle is kind of a rather delicate process were you need a lot of patience. But I guess yours are not that firm glued since they move over time, so a sharp thin Stanley knife and some patience should do the trick.
 
In rgrds to soldering the terminals I remove the connector (loosen up the screw) for the diapragm it self and solder that before I attach it again; I don't know if the heat from the iron can damage the diapragm so I am a bit carefull here. The stators I just solder.
According the 404/Mod thread started by Spritzer you will probably get a better bass from glueing the driver more firmly in place. (have a look at the 'case' site).

 

[soren_brix]

   
I don't have an open Lambda and I can't recall how the dust cover is set up. As I understand it you have attached the sorbothane to the edge of the 404 driver, i.e. the what you show as green in your previous picture of the Sigma (which uses the same driver as the Lamda).  Can it be placed on the top of the driver, i.e. what you mark as blue without interfering with the dust cover?
 
 

 
"As I understand it you have attached the sorbothane to the edge of the 404 driver, i.e. the what you show as green in your previous picture of the Sigma"; YES, I did that - I used Sorbothane on the entire circumference except where the driver terminals are on the 404's ...on the Sigma/404 there are no space on the one side of the driver due to the housing, so the green areas in the pic pretty much shows where I put the damping.
Doing the vertical part of the baffle (blue) made a significant improvement, doing the (green) is not that significant a difference .....might notice after a few weeks and then remove it again ...
 
"Can it be placed on the top of the driver, i.e. what you mark as blue without interfering with the dust cover?" ....hmmm.....since the Lambda house is screwed a bit it looks like a tight fit at least.
 
I've been listning to a few ECM recordings using my Sigma/404s (s for Sorbothane and better clarity, separation, dynamics is still what I notice.

 

[edstrelow]

   
"As I understand it you have attached the sorbothane to the edge of the 404 driver, i.e. the what you show as green in your previous picture of the Sigma"; YES, I did that - I used Sorbothane on the entire circumference except where the driver terminals are on the 404's ...on the Sigma/404 there are no space on the one side of the driver due to the housing, so the green areas in the pic pretty much shows where I put the damping.
Doing the vertical part of the baffle (blue) made a significant improvement, doing the (green) is not that significant a difference .....might notice after a few weeks and then remove it again ...
 
"Can it be placed on the top of the driver, i.e. what you mark as blue without interfering with the dust cover?" ....hmmm.....since the Lambda house is screwed a bit it looks like a tight fit at least.
 
I've been listning to a few ECM recordings using my Sigma/404s (s for Sorbothane and better clarity, separation, dynamics is still what I notice.

 
Do you have an opinion as yet as to whether the sound is better with sorbothane directly on the drivers or on the baffle that holds them?  Related to this question is whether or not it would be a good idea to add more sorbothane to whichever of these areas has no sorbothane..
 
I have found with some phones that "less is more" i.e. at some point adding sorb causes a degradation in sound.  Last night I went back to the SRXIII pro, opened it up and added some 1 mm sorb over the plastic which covers the driver.  To make a long story short, this  caused some sweetening of the sound, but also  an unpleasant bump in the bass and I ended up removing about half of this new sorb.   They then sounded good  and I spent the rest of the evening listening to these phones..  However I have some other ideas about what to do with the SRXIII and I will post the details after I get a chance to test these.
 
The bass boom has cropped up before, first with the SR003 where I also ended up cutting down the amount of sorb until the sound got balance.  Then when I recently added more sorb to the Sigma/404s the bass also got boomy.  Fortunately it's not particularly hard to find the optimum amount of sorb, "if the sound gets worse, cut back on the sorb until the sound is good."   I am curious as why this sometimes  happens but so far I have no good explanation..
 
BTW I like the "s" designation you are proposing for these modded phones (eg."Sigma/404s.")  Soundwise it's almost a new phone.

 

[soren_brix]

   
Do you have an opinion as yet as to whether the sound is better with sorbothane directly on the drivers or on the baffle that holds them?  Related to this question is whether or not it would be a good idea to add more sorbothane to whichever of these areas has no sorbothane..
 
I have found with some phones that "less is more"
 
 
BTW I like the "s" designation you are proposing for these modded phones (eg."Sigma/404s.")  Soundwise it's almost a new phone.

I need more time with the various phones, and probably also an oppertunity to remove some of the damping, before I can say anything about that.
Short term the experince from the 202 (baffled damped, like your 404s) and my 404s that are damped directly around the driver is about the same.
The Sigma/404s (I really, really love those even more now) I have damped even more (around the driver and on the vertical part of the baffle) .... don't hear that much of a difference.
I heard the Garbarek Dresden concert on ECM this evening and did some comparison with the 007mki I have .... sorry to say, but the Sigma/404s definetly have better dynamics....still the 'odd not linear' characteristic .... but I have to say, these Sigma/404s is really good. (the 007 is more delicated, more refine bla bla .... that is right, but those Sigma/404s do rock in a very attractive way )....  "Soundwise it's almost a new phone" ....couldn't agree more.
 
Please post some pics of what you are doing with the SRx ....

 

[edstrelow]

"Please post some pics of what you are doing with the SRx ...."
 

 
OK, this is a picture of what I was doing with the SRXIII pro.
 
On the upper left is the metal cover. It is made of thin aluminum and has the earpad glued to it. It is then held on the main body by two screws that also act as sleeves where the headband is attached.   You can see one of these screws on the upper right.
 
So you pull the headband off, unscrew these two screws and pull off the aluminum cover.  There are  three scerws on the top of the main body( shown with the cord running from it.) which can be unscrewed allowing access to the driver.  I didn't see much room in there for any sorb though.
 
When the metal cover is placed on the main body, there is a bit of space between it and the aluminum cover.  Stax has some minuscule rubbery/sorb type dampers here.  So I decided to try some 1 mm sorbethane there ( you can see one piece I cut out on the lower left and another  on top of the main body.)
 
When I put it back together, it was  a  tight fit and hard to get the two screws in place so I extended the holes in the aluminum covers a bit by filing with a circular file. This took about 30 seconds of filing.
 
I put the phones back together, still keeping the previously added 1/8 in sorb attached to the outside of the aluminum cover.  See previously posted picture showing a treated and untreated SRXIII.
 

 
 
The overall sound was too bassy and I went back and cut off about 1/2 of the amount of 1 mm sorb.  This gave a much better sound now.  Compared to the previous sound  (with just the 1/8 in sorb on the outside of the aluminum)  the  sound now was smoother and less harsh and the bass seemed to be both more extended and sonorous.  All in all a good sound and I spent the rest of the night just listening to these phones.
 
However I do want to try these phones without the outer ring of sorb, but with  thicker sorb between the main body of the phone and the aluminum cover.  The screw holes on the aluminum cover won't match but can be extended by the above mentioned circular file or just drilling new holes.
 
For the moment I am going on the belief that sorb is best placed closest to the drivers and here that means on top of the main body of the earpiece as opposed to the outside of the aluminum cover.   I also have one extra SRXIII low bias with perforated  drivers that I can use for spare parts.
 
Honestly folks,  if you are interested in getting the best sound from your  phones, this is a pretty interesting way to spend spend your time.This is not high level tinkering and as long as you take a modicum of care you shouldn't damage anything.  All of the effects  are reversible and sorbothane sheets are cheap (BTW it is about 1/3 the price on ebay and amazon than what the audio dealers are charging)
 
When I get a good result, which is about 80% of the time, I often just stop and spend hours/days or weeks just listening to the phones, enjoying the new sound or listening for subtle faults.  It is super cool to be able to adjust favorite phones to your own preferences.
 
In general I would say, based on almost 2 years of playing with sorbothane, that it is most effective on cleaning up the sound of the middle and upper frequencies.  The effects on bass are generally good but can sometimes go wonky.  If so this can generally be corrected by reducing the amount of sorb.
 
However there are a range of other sonic benefits such as better space between instruments and dynamics as soren_brix notes.

 

[soren_brix]

  ...
In general I would say, based on almost 2 years of playing with sorbothane, that it is most effective on cleaning up the sound of the middle and upper frequencies.  The effects on bass are generally good but can sometimes go wonky.  If so this can generally be corrected by reducing the amount of sorb.
 
However there are a range of other sonic benefits such as better space between instruments and dynamics as soren_brix notes.

These 'new' Sigma/404s still impress me a lot; I have been listning to a lot of different records since the mod, and the overall impression stands.
I'd say that people should at least try this; it's rather cheap and totally reversible - although in my case it is not reversible, since the improvement is so significant ...'S' for significant, Sigma/404s ;o)

 

[edstrelow]

These mods show that most headphone designs are  inadequate and that the designers have missed something basic, going back to when  the first phones were made. Possibly it didn't matter before there were high performance designs.
 
So far  I have only sorbed one set of dynamics and it seemed to have the same effects as with the Stax, so  I doubt that this is just a Stax or electrostatic problem. As best I can tell it has to do with getting rid of earcup vibrations caused by the basic operation of the drivers which is not being effectively dissipate.
 
  I discovered this by accident.  Many months ago it would not have occured to me to try this stuff on headphones. I had used sorbothane footers under  things like turntables but I would have assumed that just sticking it on an earcup would have no effect whatsoever.
 
Instead,  my 2 Lambdas sounded better after adding the sorb than my unmodded 007.  Upgrading the lambdas this way cost less than $1.00/ phone. Upgrading from a current Lambda to an 007 will cost in the region of $1,500.  For anyone looking for a sonic upgrade, unless you just like pissing money away, I suggest you try this first.
 
Re: the modded Sigma/404,    of all the Stax phones, I have so far tried the sorb fix on, the Lambdas (404 and LNS) have sounded the best to my ears. And by this I mean, improvements across the full frequency spectrum with no frequency anomalies( I did have bass problems on my first attempts with the Sigmas).  At the same time adding air and dynamics.They are historically related designs and use the same drivers. The mods on the other phones are good but  I suspect could be better although this may take a lot of trial and error. 

 

[soren_brix]

  Instead,  my 2 Lambdas sounded better after adding the sorb than my unmodded 007.  Upgrading the lambdas this way cost less than $1.00/ phone. Upgrading from a current Lambda to an 007 will cost in the region of $1,500.  For anyone looking for a sonic upgrade, unless you just like pissing money away, I suggest you try this first.
 
Re: the modded Sigma/404,    of all the Stax phones, I have so far tried the sorb fix on, the Lambdas (404 and LNS) have sounded the best to my ears. And by this I mean, improvements across the full frequency spectrum with no frequency anomalies( I did have bass problems on my first attempts with the Sigmas).  At the same time adding air and dynamics.They are historically related designs and use the same drivers. The mods on the other phones are good but  I suspect could be better although this may take a lot of trial and error. 

As far as my experience the Sorb needs to be added at or very close to the origin of the vibration in order to be a clear improvement.
 
@Edstrelow: "I did have bass problems on my first attempts with the Sigmas" - but you were addind the sorb to the chassie rather than the driver or close to it, right?
 
As for the Lambda/Sorb improvement, I've done two different types of Sorb'ing on a 202 (Baffle) and a 404 (around the driver itself) , and the improvement are about the same.
The Sigma/404s has both Sorb on driver and baffle, but due tolack of proper space it cannot be done to the same extent as on the Lambda's.
 
Comparing the Lamda/Sorbs to my 007mki is still in the favor of the 007mki.
Comparing the Sigma/404s with the 007mki is kind of another story since they excel in different areas; after doing the sorb mod to the Sigmas they get a lot more listning time than before. Might be a matter of preference/taste. (the 007mki as unaltered).
 
As for dynamics, I have a BeyerDynamic DT990 Premium....that has some boomy/treblish signature that works ok for electrical music but certainly not for any acoustics. I have added small pieces of sorb around the driver and onto the back of the driver - not much, because the space is very limited - but the result is about the same. It still have the signature but the sound is definately more clear and dynamic in comparison