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The important being the result!
Some advances in the war against mechanical vibration distortion. First, my portable Stax system and cd player. The phones, (the same as the SR003) show the latest bit of sorbothane damping on the headband, strips of 1/4 inch 70 duro self-stick on top and below the band and loosely wrapped with electrical tape. There are also 2mm thick pieces mounted between each driver unit and the headband,
Also note the same make of sorb pieces under the cd player. The machine sits on the outer three pieces, the inner pieces are for additional benefit. If you have a portable cd player you may notice that they tend to vibrate when playing, rather like off-balance car tires, getting especially bad at some rates of revolution. The problem is that the discs are not entirely true and round or possibly unbalanced in thickness. Anyway a cd player is an ideal candidate for damping. The total package is awesome, I hardly missed my main set-ups while I was travelling. Regular cd players have the same problem with vibrations, but you probably won't notice it because the mechanism is mounted inside. One day I will rip open a couple of my old players to see what I can do in the way of internal damping.
The second advance is that I have found that loose wrapping of sorb on headbands with electrical tape is as effective or more than the little clamps I had been using for experimentation. Since I had found that the clamps sounded best only lightly tightened, I thought that taping might be just as good. Now you can see that there are sorb pieces on the covering the underside as well as some on top. I will probably end up covering the entire top but for the moment I am just enjoying the superb sound of these Stax Sigma/404's. http://www.head-fi.org/t/175556/the-sigma-404-a-new-stax-headphone
Taking my own advice about damping a cd player I opened up my mid-low end Sherwood today and placed a bunch of small pieces of 1/4 inch. 70 duro self-stick sorbothane in various locations. The result,a big sonic improvement, reduction in harshness, better timbre and spatial imaging.
I am not the first person to relaize this and I am sure more than a few companies are doing similar things in amps and the like. Some years ago I first read that the English company Naim was putting sorb on circuit boards. A few years ago I was at the CanJam in Orange County and was sitting around talking with people the night before the show opened. I was talking with one of the engineers from Schitt and after telling him that I was putting on a demonstration of sorb in headphones, he told me that Schitt used a custom order of sorb. I wish now that I asked him for more information.
Getting back to cd players, I suggest running it for a while before before using sorb so that you can find where it gets hot. You don't want to install sorb near hot spots. And obviously check to make sure you are not obstructing any moving parts.
If you look up ultra high end cd players you are generally going to find that they are very heavy so as to control the vibrations. I see a current Naim player which weighs in at 45 lb. I am sure this helps, but sorb can turn a light-weight into something sounding more like a heavy.
The HE-6 is know as "power hungry" because it has 84db/1W efficiency vs. like 108db/1W like the Denon/Audio-Technica/JVC and every other mainstream lineups. It's true and a good speaker amp does both commit power to them and gives control over it. I've heard my 4-pin HE-6 off of both speaker amp and regular head-amp and there's no contest.
However, I'm also all about modding them to bring whatever I can out of them and I have always wondered about doing the 2 things you said: stupid SMC->mini-XLRs swap, then Sorbothane damping.
I'll follow up most on this via PM as I'm very excited about the potential now given your feedback.
Just for confirmation, was the "blue ring" in your pic blue-tac or something like it? I couldn't understand that, but previously the blue-tac mod was for driver damping.
My HE-400's(Not 400s) have undergone a incredible transformation for $20 worth of sorb. I did add 4 pieces to each outer cup which has also contributed to the sonic improvements. I find this to be well worth the trouble and the lack of ascetics. Not as much as installing them inside the cup surrounding the driver, but worth it nonetheless.
Please keep in mind this mod is totally reversible. In fact it's a lot easier to remove the sorb if you so desire. I don't think any anyone would, but the option is there. So what does anyone one have to lose, $20?
Just to keep things in perspective, I purchased custom made hi-end cable for $160 and the sorb mod had a more dramatic improvement for $20 and a little elbow grease.
I have put (suggestion of ilmothedude of the he-400 thread, thanks to him ) 9 pieces of self-gluing sorb duro 70 on the white plastic grid inside the he-400, in surplus of the pieces put there already around the driver.... I must say that the improvement was immediate , more soundstage, and more naturalness of the timbre... Sorb. is an audio success story...
in fact I did the 2 modes at the same times, the pieces of sorbotanes are separated by a little spaces, the bluetack will feel the spaces remaining between the sorb. I did a spaghetti with the bluetack because it was the easiest way to apply it (it was certainly a copy because I bought in a dollar store). The last vesrsion of pieces of sorb was a little shorter.
I replaced the original plastic ring by the aluminium one to be able to tighten more evenly.
I had a lot of difficulties to remove the plastic ring because in my headphone (~2011 ?, 4 screws) the plactic ring was strongly glued to the driver! in 2 points (north and south). I used a round strong knife and I insert under the ring and broke the point of glue! (be careful you can broke the plastic ring! but anyway the goal was to replace it after all!)
I'm pleased you try because you will not believe the result!
It's a shame they have neglected the dampening aspect of the headphones, the improvement are so huge!
My next project will be to replace the plastic cup by a nice wood cup but thinking about it. I will not reproduce the original cup (to fragil in wood) I will take inspiration from the Kennerton Odin
I found out something that markedly improves the benefits of sorbothane damping today and it costs almost nothing to do. What is it? Adding 2 layers of electrical tape as backing to the sorb. I tried this with the SRXIII pro, with interchangeable fronts, which I use as a test bed to compare the sound of a front with regular 70 duro 1/4 inch self stick sorb, with the same sorb backed with tape.
To backtrack a bit, I have been in touch with Keith Howard who did the measurements of mechanical cross-talk between earcups through headbands which I noted previously. See p26 of this http://www.politicalavenue.com/108642/US-MAGAZINES/Hi-Fi%20News%20-%20July%202016.pdf in HiFi News and Record Review.
He pointed out to me that my procedure of simply applying sorb to a surface has a name "extensional" damping. However "constrained layer damping" i.e. backing the sorb up with other materials, is generally more effective.
I have done experiments previously clamping sorb to the headband surfaces, something which is similar to constrained layer damping. There I noted that I did not need to apply much clamping pressure. In the end I used very little pressure and in fact replaced the clamps with electrical tape wrapped loosely around the sorb and headband and found I was getting as good, if not better results as with clamping.
However now I am getting great results with no pressure at all, merely adding a backing of electrical to the sorb. This is pretty easy to do and dirt cheap. l I keep finding that you have to let the modified phones sit for hours, if not overnight to really hear the differences properly. I suspect it is a combination of the glue having to cure and the fact that you have messed up the mechanical properties of the sorbothane by compressing it while you are working..
Is it possible that other backings may be better, eg. more layers of tape, plastic or metal? I may get around to looking at that. However, the SRXIII surface is curved so putting a solid material would be tricky. In any case, I have previously found that wrapping the sorb with tape was as effective as using clamps which were of course solid.
Mostly I just want to open up some phones that I have already sorbed, and add some backing. Next, on to Amazon to buy more tape!
This is super, fcukking interesting! I've been looking at applying some constrained layer damping on my PC source and DAC using some kind of treated/coated sheet steel glued to the duro70 Sorb, with the self-stick backing of the Sorb connecting to the metal chassis of the PC and DAC. I haven't gotten to it yet, but the feedback and resources showing the benefits of constrained layer damping are many. From what I've gathered, having another stiff material like sheet steel or PCB makes it most effective. I can see how electrical tape would work, but from reading what I have, I'd say optimally the outer layer should be stiffer and heavier material; just like sheet steel. I'm no scientist, though, so maybe it's not too critical as long as your constraining both surfaces of the damping material (the Sorb).
If you're dealing with a curved surface, this should work fine as long as the glue/compound you're attaching the formed sheet metal to the Sorb with was high quality/bond. It should in fact help keep the self-stick side of the Sorb curved and stuck to the headphones.
Man, if this pans out and is the case for Sorb on headphones as well as metal chassis, I'm SUPER PUMPED!
It is possible that other backing could be more effective, particularly in a different application. I mean, it could be that 10 layers of tape is better than 2. But part of the reason I don't think a solid surface matters here is that, as you will see in other posts, I originally started out using plastic and metal clamps. So these put a solid plastic or metal surface to the back of the sorbothane. What I found, fairly consistently, was that I got best results with only minimal pressure. Then I tried replacing metal clamps with tape, loosely wrapped and still got as good results.
But there is a lot we don't understand about this, and I have only added a few data points to what is probably a complicated multi-dimensional problem.
Let us know what you find.
I think a metal clamp, which equals = a metal surface + pressure - no self-adhearing glue, is not comparable to a freestanding metal surface without pressure + self-adhearing glue. I'm not trying to be a dink, I just don't think your original clamp is automatically comparable to a glued on, correctly sized piece of sheet steel.
But besides that, yes, it's totally possible that several layers of continuous electrical tape, fastened beyond the extremities of the Sorb, is better than the cut to size sheet steel.
I'm filling in what I read about constrained layer damping before this and saying there isn't a direct item that should point us to think otherwise, though otherwise isn't an issue to look into.
i have always compress SELF-adhesive sorb. only on the headphone with paper metal clamp, but my preliminary results with he 400 with 2 pieces of sorb. between the 2 cups wich are taped now there seems to confirm Ed experience with the tape, i think paper metal clamp are no more needed (hurrah!) , tape will do the job....
the mystery is : for the other pieces of gear, speakers for example, if i substract the load or a great part of it compressing the sorb. wich are on top of the speakers and under them, the result is negative, the imaging is less, and with less sparkle sound...
A beginning of answer perhaps is linked to the fact that the level of compression that would be necessary to apply is different for different level or vibrations frequencies, function of the mass and volume, shape and origin of the vibrations , of the vibrating gear...
Though i have also with great effect many pieces of sorb around the woofer and tweeter of the speakers that are not taped nor clamped, only glued in place, and this sorb. also clean without compression some negative resonance of the speakers membrane...I will wait for some scientific explanations, because sorb. work more or less optimally, compressed or not, depending of these different factors: mass,origins of negative resonance from the gear, shape, etc .....
P.S. By the way my experience with crystals are no more in the beginning and the results with a fully sorbothanized sound system is ASTOUNDING! Each crystals species have audible diffferent results, hence experimenting is key, but the effect is the most extraordinairy upgrading one i have experience, but remember that it is necessary to use sorb. before to clean negative resonance and vibrations otherwise the results would not be audible on the same level....THEY ARE 2 PLAGUES IN ANY AUDIO SYSTEM : VIBRATIONS and EMI ....
There are so many variables at work here and so many permutations and combinations of materials to try. I would not make the mistake of assuming that any of my direct comparisons using the SRXIII phones give ultimate results of what is the best technique for damping, any more than I assume that sorbothane is the best material. All I can say is that it gives good sounding results and in a direct comparison works better than blutack. My comparisons are just that, x is bettervthan y in this specific situation. Change the situation and you mat get different results.
What we really need is some way of measuring vibrations in the earcups and headbands. I liked what I saw being done in Keith Howard's measurements referred to above. The waterfall graphs look especially interesting for showing how energy decays in a headphone. My only quibble with that is that you need to measure vibrational energy in the headphone structures as well as acoutical effects. His measurements are, I believe of airborn sound.