[4mayday]

I always enjoyed the sound of my old good AKG K 340. I never used them often and intensively, just periodically, but quite regularly. Some circumstances in my life didn't allow me to use AKG K 340 almost last two years. And when I connected them after this long 'vacation' - I was really shocked! I did not recognize the sound at all! Now K 340 sound very dull and flat, with no dynamic or punch. It feels like the ears are tightly filled with a cotton. First I thought it was no high frequencies at all! But actually HF are still present - they only became very quiet.
What could happen with my headphones? Any suggestions?
Thanks.

 

[musicman59]

After sitting for that long they may need a little bit of burn-in time. Leave them running for 40 to 50 hours straight and then listen to them again. Hopefully that would do the trick.

 

[Ro-amp]

Funny coincidence? couple of minutes ago I was reading about the bass heavy version of the "340", the words you use is exactly what they implied of the normal version.
They are apparently very hard to drive...
So my guess is that they are fine and it is just their sound signature badly or not amped after a long time away from them...
However you should investigate further...
Cheers

 

[4mayday]

Thanks!
After running my AKG K 340 sonds better, but still HF level is a bit lower, than before.