Originally Posted by Shadowboxer
I absolutely let my system warm up. There is a noticeable difference after about 30 minutes. Music tends to sound much more organic and effortless once the system is warmed up.
Easy way to prove it's the system and not your ears; listen to a song you are very familiar with immediately after start up. Then put the system aside and let it warm up (play) for about 30 minutes. Them try the same song again - presto! Since you haven't been listening to it for the last 30 minutes, it's not your ears 'getting used to it'. How can they get used to something they have not been listening to for the last 30 minutes?
I only hear the difference if I keep my HD280 on my head for a while. If I put them down, and back on my head they don't sound as good. If they are on my ears for 30 minutes, then they start sounding amazingly warmer (which is a surprise for HD280s which are usually too transparent and high). I think it has something to do with them being closed, and the air pressure being different inside the cups. You ear drums have to get used to that pressure before you hear things properly.
This probably isn't as evident with open headphones.