[aeromojito]

You could try some felt or cotton cosmetic pad rings directly on the back of the drivers.

 

[AudioCats]

Got a chance to listen to a pair of Sony ZX-770BN:
 
(with noise-canceling turned off clean sound, open stage, good mids. Bass is a not quite as strong as I would like but it is not weak either. No voice "graininess" like what I heard in the Bose. Sounds quite good. somehow I felt the sound might be "simplified" (therefore cleaner sounding?). The main complain is in the upper-mids/treble region, it has some sharpness that could irritate me after a while, this problem remained after lowering listening volume. Not sure if I will get use to it after a longer listen.
 
The ZX770BN is Very comfy.
 
I only had a pair of Level-2-KSC35 with me when auditioning the Sony. In comparison the L-2 sounds congested, very up-front with a small stage and with more distortion. But the sound is "full" and somehow easy to get use to.
 
I probably picked the wrong base phones, maybe I should have started with ZX-770BN or ZX-780DC, at least they are more comfy and Sony electronics inside should be pretty good as well. These Sony's are not that much more expensive than the SkullCandy. Changing drivers should easily solve the upper-mid/treble problem. But the Sony's don't come in Blue color.....

, (maybe that was the real reason why I chose the SkullCandy's).

 

[AudioCats]

Level-3-SR
* 560uf/6.3v OS-CON as output caps
* drivers changed to Grado SR80 drivers.
* 1.5 gram of Acousta-stuf per cup as stuffing.
 
The sound signature is somewhere between L-3-770 and L-3-PX, in about everything (bass quantity, bass quality, vocal smoothness, detail retrieval, clarity, etc). I like the sound, more engaging than the L-3-770, and cleaner than L-3-PX.
 

 

[AudioCats]

Final thought on my SkullCandy Hesh wireless experiments:
 
* If you already have the phones, I'd highly recommend at least a level-1 mod, it is easy to do, costs very little, and helps the sound quite a bit.
* Leve-2 is probably not worth the trouble. It is better than level-1 but the added clarity also helps to expose limitations of Koss drivers. Plus, if you are willing to go through the trouble of changing output caps, might as well find some better drivers and go level-3.
* in Level-3, the L-3-SR ( Grado drivers) seems to be a happy middle-ground, the drivers are easy to find ( eGrado's are widely avaialble for $50) and the result is good; Beyer 770 drivers are expensive, not readily available, and too capable for the bluetooth (exposes the limitation of electronics)  ==> L-3-770 is not recommended.
 
If anybody needs help with  Acousta-stuf and/or Koss drivers, I have some extra laying around, just PM me.
 

 
(Bluetooth phones are alright, as long as they are in blue....)

 

 

[DavidA]

That's a whole lot of experimenting you did there.  I'm surprised that the SR driver does sound okay in a closed cup.  What do you feel is the most important feature that needs to be addressed to use the SR driver in a closed cup?  A friend loves the Grado sound but needs a closed headphone while at work.

 

[AudioCats]

Probably the stuffing. In my experiment these SR drivers seem to like 1.5 gram stuffing per cup (1 gram sounded hollow and 2 gram sounded lifeless). Of course changing the cup size might change everything as well. And the ear pad size also matters, I tried a larger oval pad with the L-3-PX and the sound was tiny with weak bass....
 
I think the L-3-SR is good enough to recommend but please keep in mind that we are still talking about low price bluetooth phones here, the sound will still belong to the low-fi category, just how "acceptable" it is.

 

[DavidA]

Since I will not be limited to Bluetooth it might be easier to find a closed set and just add either the Nhoord or Ypsilon driver to it.  Another project I was contemplating was getting a HE-350 and installing some Ypsilon drivers in it since another member made a LCD-3/Ypsilon hybrid and seems to like it and then another did the same and confirmed that its a great pairing.

 

[AudioCats]

 
Level-3-SFI
 
* drivers are orthodynamic SFI tweeter, 32 ohms
* sound output is very very low. Even at the highest volume setting it is not loud enough to get the "rock" feel.
* very bright, though that can probably be ameliorated by different damping.
* good vocal.
* bass is weak but quality is very good.
* doesn't feel to be any more resolving than 770 drivers.

 

[AudioCats]

  Since I will not be limited to Bluetooth it might be easier to find a closed set and just add either the Nhoord or Ypsilon driver to it.  Another project I was contemplating was getting a HE-350 and installing some Ypsilon drivers in it since another member made a LCD-3/Ypsilon hybrid and seems to like it and then another did the same and confirmed that its a great pairing.

I guess what I was trying to say is..... the SR drivers sound quite ok in the L-3-SR, considering this is a bluetooth phone (which I have rather low expacation/requirement). Not sure if it can still be considered as "ok enough", once the bluetooth "excuse" is taken out.

 

[Sonic Defender]

You should really listen to a better Bluetooth headphone. I moved from an Oppo PM3 driven balanced with a custom cable for an Onkyo DP-X1 and went to the B&O H7 and thought the sound quality was easily on par. I also owned and loved the B&W P7 wireless and would not say Bluetooth is much of a compromise if at all, frankly. Depends on the quality of the implementation and hardware of course.

 

[AudioCats]

the models you suggested are more like "the best" bluetooth phones, instead of "the better" bluetooth phones.....
 
I do agree that the bluetooth transmission itself probably doesn't cause much signal degradation, but at least the amp sections is likely still compromised in a bluetooth phone, hence my lower requirement on bluetooth phones. But they are convenient and enable me to listen a lot more, I really like the mobility.
 
Maybe I will get a pair of P7 wireless one of these days to try out. 

 

[Sonic Defender]

  the models you suggested are more like "the best" bluetooth phones, instead of "the better" bluetooth phones.....
 
I do agree that the bluetooth transmission itself probably doesn't cause much signal degradation, but at least the amp sections is likely still compromised in a bluetooth phone, hence my lower requirement on bluetooth phones. But they are convenient and enable me to listen a lot more, I really like the mobility.
 
Maybe I will get a pair of P7 wireless one of these days to try out. 

You should. I used to think that the amplification and DAC sections that could be so small must sound significantly compromised. Frankly, they sound pretty darn good, and the P7 wireless is indeed a great sounding example as is the B&O H7 that I owned as well. In the end the driver is of course very important and just as much as you well know the enclosure is also critical hence why the better Bluetooth headphones sound that much better than the budget offerings which don't have anything particularly strong about them. I'm not one of those only the best is good type of person, far from it, but until you cross a certain design parameter threshold, the sound can only be as good as the sum of the parts ultimately so to a point price and components do matter.

 

[AudioCats]

agree. The transducer is usually the first bottleneck though, the difference made by electronics will only show once the drivers performence have reached a high enough level. I kind of suspected the electronics in the Hesh might not be able to keep up once the driver reached Grado level (Grado drivers scale..... Koss drivers, not so much).
 
Anyway, the SkullCandy modding is not about creating the best bluetooth phones in the world, it is more about getting the most SQ improvement with the least effort. Looks like that "point of diminishing return" was reached quite quickly, at just L-2-KSC level.
 
By the way, since you are one of the Bluetooth gurus.... have you use the Audio Technica Pha50BT amp? how does it compare to say Sound Blaster E3/E5?

 

[Sonic Defender]

  agree. The transducer is usually the first bottleneck though, the difference made by electronics will only show once the drivers performence have reached a high enough level. I kind of suspected the electronics in the Hesh might not be able to keep up once the driver reached Grado level (Grado drivers scale..... Koss drivers, not so much).
 
Anyway, the SkullCandy modding is not about creating the best bluetooth phones in the world, it is more about getting the most SQ improvement with the least effort. Looks like that "point of diminishing return" was reached quite quickly, at just L-2-KSC level.
 
By the way, since you are one of the Bluetooth gurus.... have you use the Audio Technica Pha50BT amp? how does it compare to say Sound Blaster E3/E5?

I really liked this mini thread and I like what you were working toward and achieved with finding the SQ points of improvement/limitations. It made for an interesting read. I actually haven't tried enough BT devices to be anywhere near knowledgeable. I did own the Creative E5 and was overall quite impressed although the forced DSP I found gave it a little bit of a processed, hyper-detailed sound lacking a little warmth for my taste. The new FiiO Q5 is a device I'm quite curious about as it will have dual AKM dacs and Bluetooth as well as modular amplification units. I have more experience with Bluetooth headphones, but even that isn't exhaustive by any stretch.

 

[AudioCats]

The Fiio Q5 seems interesting but the size is too large, kind of defeats the "ultra mobile" purpose of bluetooth....
 
I gave in to "the urge to know" and ordered an AT-PHA50BT to try it out (reads: to take apart). Lets see if the DAC is as good as the one in the E3.