I had the same issues with these headphones fatigue and ringing at low volume levels.  It could be that I had an r3 (I do not know which version I had)  as it has been several months since I purchased my pair, but you are not the only person who has experienced this issue.  

It could be your source as well. Since these phones are fairly sensitive, if you at listening to them at very low volumes, your source itself may be unbalanced. This happens to me when using porta pros with an old corda move amp at low volumes. The last thing I would try is to increase volume to...

the ultrasone pro models, especially the 550 and dj1 pro need more power then an ipod can provide to sound decent.  I would not recommend either of those phones for unamped portable use.  

Quote: Hmm, I was wondering how much the E17 does for the PRO900...  Not too encouraging.

Interesting.  I guess there could be a burn in effect or they could have been a defective pair, although I dont know why both left and right drivers would be simultaneously effected unless it had to do with the wire.

Hey everyone, I wanted to share my experience with these phones. I read the reviews about some people not getting these phones to fit right and hence the sound was horrible with lack of bass. Since I have a big head, I decided to give them a try and had the same sound issues.  I wear glasses and...

I prefer my uptowns over Koss Porta Pros (I have both).  It is comparing apples to oranges since the portapros are open vs closed uptowns.  THe sound of the uptowns is more balanced vs bassy portapros.  I use both at work, and have found that I am not using the portapros near as much anymore.

Hi everyone, what would you recommend as a decent portable amp for the 900s?  I ask for both the amp on its own and amp/dac combo.

Quote: All of their new line, but particularly the 7100.  Let me see if I can explain it.  Instead of having a headband holding a separate cup with the driver like traditional cans such as D2000, D5000, ultrasone (although many think they are ugly), etc...  These cans are adopting the one...

I guess I don't get the new Beats look on phones like Dennons new line. Not attractive at all. Hopefully they will sound better then they look.

Looking at the $1050 price and $699 current quoted sale price, I think ultrasone made a mistake painting these guys white and calling them Dj phones. I believe the pioneer hdj 2000s are on the upper end of what djs are willing to spend on work phones and the look and branding may be unappealing...

I agree with fhuang about the 900s as I currently own a pair. It's not that the highs are emphasized as much as the recessed mids that make the phone sound "unique". You either like it or don't and probably is dependent on the genres of music you listen too.

I Dj as a hobby and have always kept my Dj phones separate from my other phones Ihide for casual listening, I have a pair of Ultrasone DJ1 Pros that I Dj with that cant be driven very well by my iPod and iPhone. Dj phones tend to be ruggedly built with emphasis on bass (although this is not...

I am an ultrasone fan and am curious as well in how they perform. It is interesting to see Dj branded head phones continuing the price climb into higher end audiophile territory. I Dj as a hobby, and personally I would never buy a $700 headphone to Dj with. I have a pair of dj1 pros that I use...

Thanks jerg. It very well may be where the he-400s peak in the highs, One question about the FR charts as I still do not know very much about the technical side of things. Does the characteristics of headphones change at different volume levels. Would the FR charts be different at very low vs...