[brawl]

Hello, it have been true love for 3 years. Now I have a problem with those headphnoes but I wish to solve it if it's possible. The problem is that the right speaker produce a notable
 trembling (only with very bass frequencies). at first I thought it was the plastic that was shaking because of the low frequency. then I tried to remove the foam and hold the speaker. tremor has continued the same.
I did not completely disassemble the speaker. I just removed the foam. I also tried to replace the plastic that holds the foam rubber with a sheet of cork (I tought it could improve the sound quality). 
 
I will be grateful for any suggestions. I love my headphones and I would like to save them.

 

[brawl]

I have done another test. The first sound from this trailer. 
 
https://www.youtube.com/watch?v=YGzhgDiiSgw
 
can you tell me please if you can hear that trembling please? 
 
it's really strange some times I can notice it. sometimes I cannot. 
 
I mean the really first sound effect when the video starts. thx!

 

[ROOMBAZOOM]

Hello Brawl.
 
I think I had this type of acoustic problem on a Koss PortaPro, once upon a time.
The sound kind of rattle at deep bass sounds on one side.
And I found the reason why:
Actually it is a mechanical intruder touching the moving membrane when heavy bass come on soundtracks.
Some hair - even tiny ones or barely visible ones because blond in color - are stuck between the membrane of the driver and the plastic part(with holes) that protects the driver.
In 3 years time thin hair managed to find their way through earpads and foam easily.
 
Try to gently remove hair in this area - with some adhesive tape of some sort if hair is seen coming out - and this disturbing sound on sub-bass will disappear.
Thus, be carefull not to touch the membrane of the driver while removing hair inside.
Membrane is fragile and its shape could be damaged applying pressure on it.
 
Hope this will help.
 
Regards.
A french portapro lover.