Okay, so I received my second pair of JVC HA-S500 and as promised I will share my experiences regarding burn in.
I've had pair A for 5 weeks. I've listened to them for roughly 4 hours every weekday, a lot more on the weekends. I'd estimate I've got at least 150 hours on them.
Pair B arrived two days ago. I marked the old pair "A" and the new pair with a "B" by using a small piece of masking tape on the driver housing, beneath the pads, without covering up any ports (on flat plastic). Both are identical and there is no way of knowing which is which without taking the pads off.
I prepared a simple test, not the most scientific, but I tried. I invited a friend who is also into headphones and I asked my sister to help. We each had a piece of paper and a pen, on which we attempted to write which pair we thought we were listening to. We each had a playlist of songs on our own DAPs (I figured we would be better able to identify differences using a set up we were personally familiar with) I used FLAC files on my Cowon C2, and he used 320kps files on his Ipod Classic. To start we both picked a pair at random (at this point there was no way of telling which was which) and listened to two songs from our playlists. I then asked my sister to take both pairs from us, go into a different room, take the pads off, jot down which one we had each listened to, put the pads back on, and using
www.random.org, assign both of us a pair. We could either get a different pair, or the same pair. We repeated this 10 times. She got very good at taking headphone pads on and off. Finally, after a break, we repeated the process 5 more times, this time listening to the same song every time.
To summarize the results for you: We were completely unable to identify which set we were listening to. After thorough discussion, we both agreed they sounded pretty much identical. I can't help but wonder how different the results would have been if we had been told we were receiving a different pair each time. Would we have forced ourselves to find differences which didn't exist?
Granted, this is not a watertight test. By any standards. But is it any less objective than the usual personal accounts of burn in on this forum? "I listened to this set of headphones out of the box for 10 minutes and it sounded X, I then left it playing inside a drawer for 10 weeks straight and when I came back it sounded Y"
So there you have it. In this Ork's opinion there is no such thing as burn in. Enjoy your S500s straight out of the box, because they already sound great.
