[armyowalgreens]

Wow is really the best way to describe the transformation. I've never had a pair of headphones change so dramatically. 
 
Admittedly, I was fairly disappointed in the 550s when I first received them in the mail. They sounded extremely twitchy and distant with almost no bass response. I'm not sure if the burn in experience has anything to do with the fact that these are massive drivers (50 mm). 

 

[ricerocket]

I thought the same thing when I bought my second pair for my office.
 
Someone mentioned it might be the pads softening up to conform better to your head. Whether it's actual burn in or changing shape, there's a pretty big difference.

 

[RTTO]

Cannot agree more. My pair arrived last nite.
With the player EQ settings for my current ATH-WS55, the bass response from the spanking new K550 is almost like listening to AM radio.
After setting the player bass to the max and the bass on the e17 to +4. Faint bass (thump from drums...) can be detected.
During a 6 hour listening session. Constant adjustment to the bass settings is required for every 3 to 4 songs as the bass getting more and more noticable. It is that dramatic!
 
I am not a audiophile or the like. In layman terms, the vocal sounds clearer and fuller than WS55 which had been in constant use for almost a year. The rest is unknown as it is still morphing...

 

[macgig]

The burning process seems quite magical! I returned one because of  no bass

 

[RTTO]

After 4 days of listening, I am sold. It is better than WS55 in every aspect. I think it is an unfair comparison between the two.
Obviously, the comparison is valid only when the K550 is performing in its intended condition. ie. after some warm-up. The warm up time is getting shorter each day. The transition is very abrupt, Like listening to a song with the vocal and everything being very thin and distance. Then, all of a sudden, the full sound came out. It's like the singer and the whole band suddenly approached the microphone from 20 ft away. As a side note, the E17 is only required for the first day of listening. Once the unit opened up, seemed like amping is no longer required.
Another thing noticed is that the K550 can be driven to very high volume without any degradation. I can have the player and e17 (+6 db) volume at max and listening is so enjoyable. Where the WS55 becomes harsh when the player volume reach about 80%.   

 

[peetz]

I have just taken my first steps and got myself a set of K550's and an Fiio E17.  I'm keen to find out how exactly you did the burn-in?  Was it through listening to music or did you use white/pink noise?  Also, what sorts of volume are we talking about during the burning in, i.e. will normal listening volumes be adequate or do I need to max these out?

 

[FNgr8]

I have the same setup, I basically just listened to music for a long time (I'm a student, I listen to headphones anywhere from 5-10 hours a day).  Listening volume should be fine,  I keep mine at +6db gain and 20 volume.  I did start with +2 treble and +4 bass when I got the setup, but for the past month it's been 0 for both.  The burn in process might've been different for me for some reason, but it wasn't until a few months into my ownership (about 600 hours of listening I guess) of these that I felt they were significantly different, might've just been from fixing the fit. 

 

[peetz]

Thanks FNgr8.
 
I'm currently using +6dB gain, +4 treble, +6 bass, 20 volume.  Been listening for around 2-3 hours on average per day for about a week now (maybe 18 hours total).  It's going to take me a while to get to 600 hours at this rate!
 
If the improvements will come to me as I listen it's probably better I do that than running these overnight a few times a week.