Have you ever noticed?

If you have several headphones at your disposal..and one or more has set idle for several months, you plug in and something is amiss.

The phone in question has played for several hundred hours previously and is well broken in...but the Bass is threadbare and a bit lumpy..the treble is closed and has a nasal stridency, while the midrange is recessed and hollow sounding.

Then after 2 to 6 hrs. of healthy playback things flesh out and the balance and tonalities also timbers are as you remember.

Has the driver surround stiffened? Has the diaphragm itself loosened and lost the piston properties? Has the hole flow alignment that permitted electron flow closed, then has to realign? Is it all of the above? None of the above?

Now some of it might be that a different phone has different acoustical properties than the phone that it is replacing...granted. But after noticing that pinched unfocused quality after two minutes....then you hang them up to play sit and spin with healthy playback levels. Then return after a couple of hours to notice that things indeed have settled down?

Has anyone ever noticed or wondered?

I just got my HD650s this weekend. After hearing the HD595 and absolutely underwhelmed I have not been interested in Sennheiser much. But the HD650 always there, just taunting me (too many amazing reviews to disregard), but without the proper setup I dared not purchase and be dissapointed.

Though not perfect with an excellent tube amp, I decided it was time to jump in, and now relevant to your posting, I feel the AD900 may be neglected for a few weeks. I am perfectly happy to sit here and browse this forum using the HD650s. So far it's been a satisfying experience. But the forward, and fun sound of AD900s I believe will not be ignored for too long!