[Doppler]

Hello, 
 
I've got a pair of AKG 240s that were playing fine up until recently. The problem is that the sound has become extremely tinny, often with the vocals gone; For example, "Hey Joe" has no vocals from Hendrix but I can hear the backing vocals very clearly. If I listen to something like "Son House - Death Letter" they sound fine, with no elements missing. 
 
Some songs sound extremely cracklely, like "Rehab - Amy Winehouse" 
 
I tried contacting AKG, but they were useless.
 
Any help is appreciated. 
 
Thanks, 
 
Shane.

 

[viralcow]

Just a shot in the dark, but could it be your audio jack not being plugged in fully?

 

[Kodhifi]

I second viralcow.
 
partially plugged phones don't do L   R      they do a mono track of L minus R which is remarkably similar to dolby surround. Any center channeled material in the music would be wiped so many vocals, kick drums, etc will be attenuated or absent.
 
Sometimes the jack you plug into has plastic around it that doesn't let a thicker connector get in there all the way, like iphones with some cases. Just push that puppy on in and if it won't fit, use a short extension cable with smaller connectors.
 
If it's in there all the way it may be the connector is on it's way out.
 
If it's just one speaker that's doing this then it may be that the voice coil is not correctly seated due to dropping, over driving, etc.
 
A lot of Grado's are famous for this and the voice coil can usually be popped back into place by using air pressure, like carefully using your mouth to suck in or blow out slowly next to the driver to remove wrinkles. Think, blowing smoke rings, it doesn't take much pressure to damage a driver so that is a last resort and should be done with extreme caution.