Ultimate bluetooth headphones: DR-BT50 with KSC-75 drivers :)
Jan 29, 2010 at 6:42 AM Thread Starter Post #1 of 3

nightfire

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Hey everyone... it's been forever!

I've been so busy with other things in my life, but just thought I'd post about (if anyone's interested) my latest mod.

I bought a pair of Sony DR-BT50 bluetooth headphones to help me survive my winter walks to work (one of the few circumaural BT headphones). All of the reviews I read raved about the sound quality, but I was quite suspicious; everything I've heard from Sony consumer has been utter trash.

As it turns out, these were no exception. I have to assume that either the QA engineer had serious hearing damage, or they were tuning it to smooth out the most appallingly compressed, hot pop music.

It wasn't just an unpleasant sonic signature; not just muddied bass and recessed mids. The cans were undampened, the earpads (covering the speakers) were thick, the drivers were aimed wrong... the list goes on and on.

It was so bad eventually I had to stop the music on my walks to work and just use them to keep my ears warm. I was so angry I'd wasted $150, and worse, that Sony got my money.

Anyway, on the verge of tossing them in the garbage or donating them to someone I didn't like, I decided to try to fix them. New drivers, new damping measures... whatever it took.

The donor was one of my pairs of beloved KSC-75s. I stripped all the housing off, and ground them down to fit the speaker mounts in the Sonys.

With a heat gun and some patience I extracted Sony's worthless drivers. Then ground out the diffuser, widened the round mount a touch, installed the KSC-75 drivers facing the right direction, soldered them up, stuffed the cases with acoustic foam, and buttoned it back up.

I replaced the (admittedly soft) felt earpads (not the surrounds.. just the part that covered the drivers) with steel mesh from a car repair kit. It looks kinda cool now.

Sliced up the original pads and used them to cover the edges of the metal for comfort.

The result is outstanding.

Of course, it's still A2DP/bluetooth, so you can detect artifacting. But aside from that, they have the same sonic signature and clarity of the KSC-75 with slightly deeper bass. No midbass accentuation. Solid mids.

I lent my camera to someone but if anyone's interested I can take some pics with my cameraphone.

All in all the mod took about 4 hours (including figuring it all out), but if anyone's looking for an excellent cold weather bluetooth headphone rig (and not afraid of some work) I'd definitely recommend it.
 
Jan 29, 2010 at 5:23 PM Post #3 of 3
Yeah it seems like a technology that isn't quite there yet.

There are two problems... one, bluetooth should have been designed from the start to scale with the requested bandwidth up to 10x its current power. That would allow it to be used reliably outdoors (and we're only talking from I think 5mW to 50mW, and only as required).

Two, because all the A2DP headsets have only been around a couple years, people are still wow'd by the whole wireless thing. There's very little competition for quality (audio, fit and finish, etc). Just the fact it's wireless is enough to sell it.

But I think it's here to stay.. give it another year or two and I bet some really decent gear will come out. Hopefully the new bluetooth spec will include a higher power radio, or maybe even merge the wifi and bluetooth radios together so bluetooth can benefit from the more powerful hardware. With my new setup I'm convinced that the compression (with enough bit depth) doesn't unacceptably mangle the audio for casual use. It feels roughly equivalent to say 256VBR... obviously no good for careful listening, but fine for walking down the street or working out at the gym.
smily_headphones1.gif
 

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