Stax SR Sigma Question

[ESL-1]

I just made a deal for a pristine set of Stax Sigma phones. The seller claims they are in perfect working order. I should have them by end of next week. One caveat, the seller was allergic to the wool damping material inside the enclosures so that is missing, he also claims he found the sound more open without the damping. Should I feel different regarding that assessment would anyone have suggestions for an easily obtainable substitute for the damping?

Thanks,

 

[ESL-1]

The Sigmas arrived Mondsy and as I suspected, without the wool damping material they sound somewhat hollow and laciking in bass. First i cut some 3/8 thick sections of foam rubber and lined the inside of the enclosures which smoothed the sound a bit. Next I purchased some wool based dampening material for speaker cabinets from MCM electronics. I just relined the inside eith some of this material after removing the foam ripubber. Sound has improved another few notches but there is still not much impact and fullness to the bass. The rest of the audio spectrum is doing well.

Has anyone experimented with this and perhaps come up with ae better mating wool filler?

Thanks for any thoughts or advice.

:mad:

 

[n3rdling]

The purpose of the mineral wool is to absorb some of the sound waves in the cups so that they don't bounce around so much.  Mineral wool is one of the best materials for this purpose, but you can also try acoustic cotton, acoustic foam, and compressed fiberglass (just be careful with that stuff).  You can also try to use thicker slices than what Stax uses. 

 

[jaycalgary]

I would just try a bag of cotton balls from the drug store. Kind of pull them apart a little bit and they mesh together nicely. I thought they made the sound good in past experiments and doesn't have the downside of other materials.

 

[ESL-1]

Thanks Jay, might give that a try. At this point the wool packing seems to be working well especially as I continue to play them. It is possible that they had not been used for a long while before my purchase.

 

[jaycalgary]

I read on here before from one of the top stax guys that they soaked mineral wool in alcohol or water I forget to get the junk out of it. Let it dry out then installed it. Sounded like a really good idea to me. I would still try the cotton balls once. It was quite a while ago but I thought I got the best sound from it. It was interesting how it could be layered denser then a bit softer. Mostly felt like I could get a bit more treble and still keep the bass. Cutting down on reflections but I could be missing the whole point of the Sigmas.