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Damping Mechanical Energy Distortion of STAX and other phones with SORBOTHANE and other materials.

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  1. richard51
    I cut mine from a pizza mesh plate i bought from a one dollar shop ( using before that a plastic grid mesh).... any grid, plastic or metal, easy to cut with not a too small square grid will do...[​IMG] 
  2. edstrelow Contributor
    I added some more 1/2 in 70 duro sorb to the 007a  and the sound again went up a couple of notches in performance, especially in the clarity of bass. The drums were tighter and the double basses growled.
    I am doing the same now with my two Lambdas. The problem they pose, like many other phones, is that there are few if any places to mount sorbothane inside the ear cups. With the lambdas, I was able to place some 1/4
    inch sorb on the back plates 102_3689.jpg  as shown here but 1/2 inch is too bulky and would extend beyond the top of the drivers, thus possible creating some reflections.
    Fortunately we now know that damping can be applied to headbands so I added three pieces to the top of my Lambda LNS.  You can see three big lumps.  These have a double layer of electrical tape on their tops as well as being glued (3M80) and loosely taped to the band. This does an enormous amount to improve the sound, again as noted above in the bass.  There is a further jump in  clarity there now and I am hearing more bass instrumentation.  But the sound is not bassy, just clear sounding throughout the frequency range.
       Why is the thicker sorb better? Because it it works better at lower frequencies, according to the Sorbothane site. http://www.sorbothane.com/   
    The way I conceptualize damping now is that the undamped phone is essentially buzzing with the Newtonian, equal and opposite energy from the driver. The buzzing gets back to the drivers both on the original ear and on the opposite ear through the headband.  Damping cuts the buzzing.  Thicker, denser sorb cuts more buzzing. 
     The problem is finding places where you can install  1/2 inch thick material. I would prefer to have these in the earcups because I suspect they would dampen more but as  note above, there is no real place to do this. As an alternate,  the headbands work well too. 
    richard51 likes this.
  3. edstrelow Contributor
    I measured the effects of sorbothane damping on the frequency response of my Polk SDA speakers using the real-time analyzer portion of my old dBx 10/20 equalizer/analyzer and calibrated microphone. Basically it showed that the bass response had gone up considerably after I applied about $10.00 worth of 1/2 inch 70 duro sorbothane to each speaker. The deepest bass was up about 5-6 dB at 30Hz which is the lowest region the 10/20 analyzes.

    Now I don't think that the sorb is actually increasing the bass but rather it is damping the higher frequencies, more than the bottom frequencies which are more or less untouched. It has been clear for a long time that the sorb lowers the volume output from phones and speakers, which is more or less what you expect if it is absorbing vibrational noise. Many pages back, I had checked this volume reduction out by ripping off some sorb strips off a set of Sigma pros. The volume went up after the sorb was removed and what you heard was a marked increase in something which sounded somewhat like ambience but was presumably the vibrations of the earcups coming back and messing up the sound. In effect the sorbothane is increasing bass by absorbing mid and upper frequency distortion. Also the website for the Sorbothane website states that you need very thick sorb to dampen the very low frequencies although it doesn't give much detail.

    Increasing bass is not a problem for most folk, where increasing bass is like a search for the holy grail. However the Polks are big speakers with a very wide frequency response. With no equalizing they measure +/- 5bd from 30Hz to 16 khz, which is the range the 10/20 measures. So they are quite remarkable in that regard, but better if equalized. Once I saw the new measurements I had to reduce the deep bass peak by a combination of reducing the bottom slider of the amplifier's equalizer and raising some of the mid range. They now sound amazingly detailed, balanced and dynamic.

    Nevertheless I intend to add more 1/2 inch or even 1 sorb if I can get it, based on the aforesaid report on Sorbothane website that you need to go thick to dampen the very low frequencies.
    Last edited: Jun 24, 2017
  4. Henery
  5. Jaab
    I have just saw this thread!
    Some comments make me smile!
  6. chrismini
    Hello Richard and Ed. Very inventive and cost conscious. It appears you have crystals installed in the grill. Could you elaborate? Right now I'm just being VERY careful with my 400s. I was listening to Bob Dylan Highway 61 and Free Wheeling and it sounded like he was 4 feet away from me. Same with Steve Earle The Low Highway. 
  7. richard51
    Chrismini, dont begin with crystals in your he-400 grill... Put agate, and amethyst quartz on top of the power transformer of your amp, only that will give you a great impact for almost no money, and no installation problem...[​IMG] The most impactful results on the headphone will be with crystals and minerals placement on the  electrical breaker, amp, dac. interconnect etc, hence no need to begin with the crystals grill mod. where the impact is less...only go with the grill at the end...  
    i listen my speakers now and the agate minerals (banded madagascar one) i have bought  on Ebay are on top of my speakers, on my speakers cable, on top of my dac, with some other crystals and minerals, but the impact of the agate was spectacular...The greatest transformation imaginable of my speakers now...I dont recognize any of my musical cd...What i can say more? it seems  no one dare to try a few bucks trick that some company sells for thousand dollars... The snake oil is not so much with  the crystals or minerals use  but with the price asked by some sellers and with the pseudo-scientific  explanations they give to justify the product... trust me with a few bucks the results are amazing...It is not necessary to pay much...[​IMG] Best regards to you Chris...
    experimenting is the key
    no crystals or minerals act  the same...the placement for example  play a great role, if you put some crystals  in the rear or in the front of your speakers for example, that would not give the same result, even few inches of displacement gives difference...Same on top or at the base..It is mandatory to try many locations...
    Any placement or change is immediately audible for the better or the worse but it takes  approx.12 hours to settle correctly for your adapting brain and ears ...
    all crystals and minerals correct themselves if added together... but you must experiment to discover the right mix and synergy...Your ears will guide you by trials and errors...After 2 month of experiment, i have reach an optimal peak of natural unbelievable  natural musicality with my system... 
    I now use agate, topaz, amethyst, tourmaline different species of quartz,fluorite octahedral crystals,kyanite minerals (but dont buy these last 2 for beginning i use them mostly to equilibrate the imaging) etc (Banded agate are my favorite minerals but it is necessary to place some other crystals to equilibrate them and for optimal results)
    all that reach at the end a new level for the most extraordinary upgrade in my system i have ever experimented...If you have already a good dac, a good amp, a good  set of speakers, and a good   headphone, forget any upgrade tentation to spend on a so call  newer better gear, rather crystals and minerals will transform your actual  good gear to a new level...You will discover that you had never listen before to your system at his optimal maximum quality level... Totl for a few bucks, and if not totl, very good upgrading effect, law of diminushing returns will apply...
    A last remark : like my experiment with sorbothane have teach me already, remember to damp your gear before buying other product for the so-call upgrading urge...After sorbothane and crystals, upgrading really will cost me above 5 thousands...[​IMG] The miracle is: i dont fell that necessary anymore...
    This is  only one of my big agate on top of my speakers ( i have others smaller one for other locations and also agate peebles  mix in  bags)
    this is the other big one on top of the other speaker...
  8. chrismini
    Those stones or minerals in the photographs beautiful! How much are they?
  9. richard51
    You prey on them on ebay when the price is under 7 dollars...You wait and with time you will have them for a cheap price...the price is relative also to the beauty of the stone, and his weigth...But remember that it is better if you buy different kind of  stones and crystals not only one species...But the  banded madagascar agate are not only beautiful but very transformative of the sound in a spectacular way( more positive change than any tube i bought for my last tube amplifier), and it is my favorite one, love at first sight!...[​IMG]
    Best regards Chris
  10. chrismini
    I have always wanted a tube amp but the good ones are out of reach financially. Plus my little HeadRoom Micro amp sounds very good and has the best crossfeed circuit/software I've ever heard. I know a lot of purist thumb their noses at crossfeed effects, but, if done well, it rids the hard left and right panning that's used/overused on a lot of rock recordings especially from the late 60's and entire 70's. For a 2 channel stereo loudspeaker setup, panning works great, but for headphones, not so much.
  11. edstrelow Contributor
    I tend to agree with much here. Of course open back speakers will have a lousy frequency response. I am personally adding sorbothane to my speakers. However given the size of speakers and the amounts of sorb needed it does get more expensive. Still the results are remarkable.

    The claim that sorb stores energy seems false. The originators claim that it transforms it to heat. I have no idea what Herbies stuff does. I have seen many reports of people putting speakers on top of sorb footers with apparently good results. I would rather have a rigid mount myself, and use the sorb for damping. Most people seems to have assumed that it needs to be clamped or held firmly to whatever you are trying to damp. However, you still get good results just attaching it to the speakers, headphones or whatever. However the adhesive must be good, the self-stick seems pretty good and i have recent bought a very expensive adhesive by Lord to hold the thick sorb which is not available with self-stick. Adding a backing to the sorb also helps, I have been using double thicknesses of electrical tape. As regards clamping, it does seem to be a better solution but you don't need to use much pressure.
    Last edited: Jun 24, 2017
  12. edstrelow Contributor
    I find the sound can be so much more realistic when the phones are damped. My thinking is that the upper harmonics are less obscured by the residual vibrations in the earcups and also that you get better dynamics (although why I am not so sure.)

    I find that so much of my music just sounds better, including really bad recordings. I was listening this morning to a real cheap set of 50/60's re-issues, probably unlicensed, and some sounding like they were copied off lp's. Yet they were all sounding very good through my Stax SR007A. These phones, and most stats tend to show harshness with such material, but a lot of that is now gone.
  13. edstrelow Contributor
    I am getting some good results with 1/2 in 70 duro sorbothane both on speakers and headphones such as the Stax SR007A. The essential problem with the 007A is a certain bass boominess. It's always had this but to some extent it got worse after the thinner sorbothane was applied.

    Sorbothane's website noted that you need fairly thick sorb to dampen low frequencies. The thinner sorbs, i.e. 1/8 - 1/4 seem to do a great job clarifying mid and upper frequencies, but sometime seem to add to the bass. My explanation is that if you are getting rid of a lot of mid and upper frequency sounds (and sorbed phones reduce volume and need to have amplifiers turned up to compensate) then you are left with more bass especially after the amplifier is turned up.

    I have recently added 1/2 in 70 duro directly to the 007A and am pleased to say that it seems to finally take care of the boominess of these phones. The first problem I encountered was where to put the sorb, because at this thickness it just doesn't bend to fasten to a curved earcup surface. So I found a smallish bit of flat area below the headband.

    How to fasten it was the next problem. Self-stick was not available for 1/2 inch, and I have been getting less satisfied with 3M 80 since it wasn't always keeping the sorb from falling off my speakers.

    Sorbothane Inc. recommended Lord 7650, an industrial adhesive not generally available. I finally bought the bullet, $35 for a 1/2 pint can, minimum order of 2 cans and I am pleased to say that it really does good job. I wonder if it may be hard to remove.

    I initially put on a piece about 1 1/2 inch long. This took care of the bass problem with th 007A but also seemed to muffle the treble and midrange. Then I remembered my own advice, "no dimension more than 1 inch" and cut the middle out. The sound was now much better in treble and mids. Two layers of electrical tape reduced a bit of too much edginess in fact.

    A lot of this work with sorbothane makes sense to me:
    1) basic Newtonian mechanical principles mean that that any driver will direct energy equal to what it is blasting into your ear, into the earcup housing. This energy is probably the source of the sonic problem.
    2) sorbothane transforms that energy into heat thus removing it from the headphones.

    But I still have no explanation for why small pieces of sorb work better than large ones.

    I was hoping to post pictures here, but the new set-up doesn't seem to let me upload these from my sd card.
    richard51 likes this.
  14. Hutnicks
    Small pieces are easier to excite due to their lower mass.
    Locktite 454 is a good adhesive choice as well but pricey. Shoo Goo will do it cheaper and has its own damping abilities as well.
    I have yet to try bicycle tyre tape. It is fairly expensive as well.
    richard51 likes this.
  15. edstrelow Contributor
    The low mass argument makes some sense, although I wonder how this plays out with the fact that denser (70 duro) and thicker (1/2 inch) sorb is more effective. You would think those two factors increase mass and would impede sorbothane excitation.

    Along these lines, I wonder if a smaller footprint allows vibrational energy to pass more easily into the sorb? I am sure a mechanical engineer could explain this, but this site tends towards the EE types.

    What is really needed to inform these problems is measurement of vibrations in headphone assemblies, but even the Mitchell article I referenced didn't do this. He seemed to be saying that one needed a strain guage to provide such measurements, which he did not have.
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