It's interesting that some recent pairs need burn-in. My last pair didn't at all, but my previous versions did.
I think based on memory, some of the pairs I had were a bit muffled out of the box. The common symptom of no burn on the DJ100 in is this weird lack of treble and a muffled sound. Crystal clear when burned in and it has the proper source and amp.
People say this stuff about no headphone can sound bad out of the box and great after burn-in, but most likely they've never experienced one of those headphones with the titanium driver or one that actually sounded bad!
Even the Koss Pro4AA series is known for needing lots of burn-in too i've heard.
I posted this in my review, but I once had a DJ100 that needed 3-5 days of burn-in to sound identical to my first. I had both of them side by side. This was actually only 5 nights of music/pink noise shoved in a drawer for 8 hours.
I guess that's a total of only 40 hours! I've never had a pair that needed more than that. I usually use really obnoxious music with the volume cranked up past regular listening volume. Not too high though.
I've had one pair that actually made me think it was defective. I even complained about it in some of my posts. I always suggest that if a pair is ever muffled or not clear to burn them in. Even for those that don't believe in burn in it's best to give them a week before judging them.
My Tony Bennett pair sounded perfect out of the box and I imagine most every DJ100/TB might sound fine out of the box, but who knows.
BTW does anyone else find the sound quality out of the Sansa Fuze LOD not as good as the headphone out? I did more A/B tests on this and the headphone jack is still clearly better sounding to me. I don't know if it's just that the DJ100 likes the extra power from the amp (since the DAC bypasses it) or what.
Sansa Clip and Fuze with headphone out to amp sound pretty similar in sound IMO. If I use the LOD cable on the Fuze, the mids are a little thinner. Very strange.
Also..did you know that external Ipod docks (the small white ones) have a DAC in them? I wonder why? I wonder what the point of having a DAC inside the dock is.
For those that have an iphone or Ipod Touch, try the DJ100 with the E5/E6 without a LOD cable. The sound is pretty impressive. The mids on the E5 are a little more forward sounding than with the E11. The E11 has a little better sub-bass it seems like.
Right now my setup is the Sansa Fuze to the E11 or Total Airhead using the headphone out. Airhead is way better than the E11, but I think the E11 has a larger soundstage. One of these days I might upgrade my Airhead to the DAC version (Total Bithead).