[Digitizer]

Hi all,
 
As the title states, I have a Beyerdynamic DT 770 Pro 80 in which the right driver is softer than the left. I've tested swapping them around on my head so I know I'm not crazy and that the headphones are the problem. I've sent it back once for repairs and they came back exactly the same with the message, "Re-soldered right driver".
 
That did not solve the problem, so they seem to have no idea what they are doing (might be something to do with the bad service everything has in my country but whatever).
 
I've noticed that someone else has had the same problem with the same model (other than the one in the linked thread is limited addition): link
 
Does that mean that this is a common problem with these headphones? Does anyone else have this problem?
 
I was wondering if I could fix them myself, so I opened them up and inspected the wires. Everything is soldered fine but I noticed that below the contact points on the right driver, the little wires that go into the driver are twisted around each other.
 
Does anyone know if that could cause the right driver to be softer?
 
Any replies or experience greatly appreciated,
thanks

 

[billybob_jcv]

Have you tried connecting them to completely different sources and amplifiers? Have they always been like this, or were they previously fine and then suddenly started doing this? I suppose it's possible the driver is wired backwards, and they are out of phase - I'm really not sure if that would cause this issue. It might just be a bad driver, or it might be something in the way the driver is mounted that is preventing the driver from moving correctly. A speaker driver is a pretty simple device - it either has electrical connection or doesn't, and if it does, then everything else is really a mechanical system, not electrical. It's really just an electromagnet being fed with varying voltage.

 

[Digitizer]

I've tried different sources. The same everywhere. They have been like this right from the start. I thought I could get over it by setting the balance on my pc but it just annoys me as soon as I want to plug them into something else, it's off balance again. I cannot listen to music like that.
 
So wires will not do this? Maybe I will start fiddling with taking the driver out of it's socket...

 

[billybob_jcv]

Like I mentioned, I'm not sure if reversing the polarity would cause this issue or not. I can't think of anything else electrically that would cause the issue - it's not like someone would have put some resistors inline just to mess with you!

It sounds like bad QC matching the drivers to me.

 

[Digitizer]

Yeah. Just sucks that this always happens to me. Why can't it ever just be right?
 
Anyways, I tried moving the left driver out of it's socket a bit and it kind of seems like it's helped now that there is a small gap, but when I did a "driver matching" test (on this page: http://www.audiocheck.net/soundtests_headphones.php), which sweeps through frequencies, it started off on the right with the low frequencies, then centered and ended off on the left at high frequency. So it's a hard problem to solve myself, if it's at all possible. But maybe... just maybe...
 
Thanks for the help though

 

[billybob_jcv]

So - the balance is frequency dependent? Wow - that really makes me suspect the phase - but I don't want to suggest reversing it unless you are confident you can get it soldered back correctly.

I'm sorry - I just don't know.

 

[Digitizer]

Nope, it looks like that was because of my "fix". I pushed the driver back to how it was, then repeated the test. Basically if I set the balance on my pc to what sounds correct and I do the test, it is perfect. So the problem really is just that the right driver is softer. It's really weird. So it can't be phase.
 
I also took them both out and removed 2 hairs I found on one of them but that made no difference. Sigh.
 
Maybe I could put a resistor on the left driver? Is that even heard of to fix balance issues?

 

[billybob_jcv]

Well, that's basically what a balance knob on an amplifier does - it simply changes the resistance on one side differently from the other. However, it can also change the sound signature a little bit. Why not contact Beyerdynamic and see if they can repair them? Is that who you sent them to the first time? I would tell them it didn't fix it and they need to make it right.

 

[Digitizer]

I guess that's my only option. As you say, soldering a resistor on would probably mess things up. I don't really want to be without them for the holidays though, so I'll keep setting the balance for now and then take them n next year. Again, thanks for the suggestions