One day I was walking around in Best Buy and came across the Koss UR-55. Since it was a new product and cheap ($40-$50!) I figured I'd give it a try. I almost didn't because I have this bad habit of buying headphones I don't need! I expected that i'd be returning them the next day.
I clearly remember first using them and they sounded very slightly muffled. After listening to them and burning them in it went away. If if don't really like a headphone right away (after burn in) I'll usually return it or set it aside and not use it for awhile. With these I couldn't stop listening to them. Even in the morning I looked forward to listening to them after work. They seem to have my preferred sound signature.
I like a lot of bass, but nothing excessive (D2000 is too much for me for example). The M50's have almost too much for me, but I'm able to deal with it. It doesn't ruin them, but I do feel it's a bit bloated. I also dislike recessed midrange. The M50s also have this issue, but it's not too bad. It's such a non-issue that it's not even worth mentioning. The one thing that annoys me about most headphones is that the highs can be very fatiguing after just an hour. The Shure SRH-840s have some of the best sound quality ever for a headphone, but the highs can be slightly harsh at times. The Sennheiser HD-600 don't have this problem and perhaps some people see that as a negative. I don't. Those headphones will never fatigue my ears no matter how long I listen to them.
I also don't like excessive details. Some things were not meant to be heard I think. Because of this I generally don't like the Beyer Dynamic DT-880 and DT-990 32 ohm versions. I also generally don't like very bright headphones suchs as the Grado 325i. The Koss UR-55 fit nearly all of my requirements and it's not like I had planned it!
I kept comparing them side by side to my Audio Technica M50's. I could not honestly say the M50s were better then the UR-55! I just could not decide. On the UR-55s some instruments sounded a lot more clear and the vocals were more forward and easier to hear. I also felt as if instrument separation and the size of the soundstage was much better on the UR-55s, however this was possible! On some songs on the M50s all the instruments sounded like they were all in one big blob. On the UR-55 (and DJ100) it was easier to pinpoint all the instruments.
The bass is also just about nearly perfect on the UR-55. It has a ton of bass, but is never excessive at all. The bass on the M50 is at times a bit overkill and I find the quality of the bass on the UR-55 much better.
I usually don't get this excited about a headphone. The UR-55s impressed me from day one. The cheap price also helps a lot. I've suggested them to people when I can, but sometimes I felt like some people were going to start thinking I work for Koss!
I've never been a huge fan of Koss headphones. I own the KSC75 and Porta Pros but never loved either of them. I must have really not liked the Porta Pros much because they somehow went missing! Back when I was 15 or so (now 30!) my friend and I were always impressed with the Koss TNT-55. This was before I was seriously into headphones though.
The UR-55s are not exactly the most portable headphones ever, but they're not exactly a full sized headphone, but close! They are perhaps one of the smallest over the ear headphones you can find. They are also semi-open. One thing that I loved about them the most is that they had a perfect fit and the comfort was very good. The earpad looks like the cheap scratchy foam you find on cheap headphones, but it gets softer after a few days.
So after being so impressed with these headphones I noticed that Koss had several other new pairs of headphones and earbuds out. Along with the UR-55 they also have another product in the "Pulse" series. I noticed they had a pair of full sized closed headphones called the PRO DJ100. They were new and my local stores did not carry them. I did a "store pickup" online and actually drove an hour there and an hour back just for some stupid $80 headphones! All the way up there I kept saying to myself that this might be getting into an even worse addiction then I thought!
I brought them home and was VERY impressed. Right out of the box even. They had a lot more detail overall then the UR-55. It was a bit more forward. Vocals are still a bit more clear on the DJ100 then the M50. Same as the UR-55. The extra details are what made these worth the extra $30 over the UR-55.
Comparing the UR-55 to the M50 I couldn't decide which sounded best. With the DJ100 it's easy. The DJ100 is clearly better in nearly every way.
When I see headphones that look similar to the Shure SRH-840 and the M50's I get a bit worried. This is because I have a small head and they probably won't fit! The SRH-840 have some of the best sound out of a headphone, but the fit is extremely poor on my head. It was bad enough to be forced to sell them and stick with the M50 that doesn't quite sound as good, but close. The fit on the M50 is much better.
So anyway, the fit on the DJ100 is PERFECT. I can move my head all around and they don't move at all. The build quality in some areas seems much better on the DJ100. There is a lot more metal, but at the same time they seem smaller and lighter. The design is a bit more simple too. I hate the coiled cord though! The earcup material is the cheaper variety, but it's not too bad and it's more comfortable to me. I imagine after listening to them for hours they won't be sweaty on my head.
Koss is on a roll right now. Most of the new stuff they've released is pretty impressive in some way. I've tried three of their new products. The Pulse Insider is good, but the bass is too much for me. Those are also compatible with the T-400 Comply foam and that could be the problem. I'll have to try some new inserts. Those have the most bass out of any IEM i've tried. They seem like a in ear version of the porta pros, but with an insane amount of bass.
The DJ100 sounds like a mix between the Sennheiser HD-600 and a more toned down version of the Beyer Dynamic DT-880! Like on the DT-880 it's now easier to spot small details such as recording humm and even tiny things after a song has ended (that I never noticed much before). Like the HD-600, it's seems to be a very natural sounding headphone. Everything sounds exactly how I imagine it should sound like in real life. Overall, this is one of the best headphones i've owned under $200. I don't know how it compares to the SRH-840, but I prefer the sound signature of this a lot more. I'll probably end up selling my M50s and sticking with this pair.