Pros: Price to Value. Soundstage.
Cons: Comfort is picky.
I've been a lurker for a long time, but now that I've got some more money and better cans, I thought I'd write a review of the AD900s.
I upgunned to the AD900s from my AD700s and an HD 555 modded to HD 595, so my review will be based on that comparison. I'm listening to these through a Asus Xonar Essence STX, and am using v0 mp3 files.
So everyone always says the AD700s and HD 595s have a great soundstage, and I'll agree, and the AD900s have an even better soundstage. It's really a cool feeling when you can listen to a song or piece of music and actually feel the instrumental separation that couldn't before. The separation is very clear and distinct, almost to the point where I would say it's almost TOO good for things like gaming, when a left directional sound almost sounds like it's only coming out of the left can, which I guess is good for competitive play, but it sounds pretty unnatural. On the downside, it makes listening to anything Glee insufferable because it sounds so fake by comparison to other recordings.
In terms of the mids and highs, there's really nothing much to say that hasn't already been said. They come through clearly and with plenty of punch, and because of instrumental separation it almost feels like you can hear things you weren't able to before in certain pieces. Anywhere where the AD700 excelled, these do even better, with sharper tones, and the HD 595s don't really compare in this department. The most noticeable places are in any song with lots of vocals, where the vocals are presented at a higher volume than the instrumentals, and in the big romantic classical pieces, where the soloist comes out much more than before. Also, in Battlefield 3, where the cracks of sniper shots become much more distinct and impactful than before.
The bass is where the Audio Technica AD700 is severely lacking, but I feel that the AD900 makes up for it in every way (although I am listening through an amp). I don't really own or listen to much electronic/techno, or other bass-heavy music so maybe I'm a bad judge of bass, but I feel like the AD900s have enough to satisfy me. Both the powerful rumbles and the sharp percussive sounds are really great here (think subwoofer vs 1812 overture cannons). The HD 595s have pretty decent rumbles by comparison, but the sharp percussive effects don't come through as well. One of the places where I really notice these coming through is in video game explosions, When done right, they don't really blow your eardrums out, but you can definitely feel the rumble in your ears. I'm someone who really isn't a basshead, but I thought the AD700s were actually quite light on bass and I think the AD900 is a marked improvement over them. I don't think I would necessarily want any more than these provide.
The design is basically the same as the AD700s, but these feel a little smaller, and have a higher, more metallic build quality. The thing I like most here is the design feels very strong and the frame doesn't involve using plastic which is one complaint I'd have about the HD 595.
The comfort is the one area where I feel these come up short. I am coming from the AD700s primarily, which I will admit are the most ******* comfortable headphones I've ever worn in my life. But where I could easily have 8-10 hour work sessions with the AD700s, I definitely can't with these. The angle of the driver is an annoyance, and they are smaller, so they fit much tighter on my head. With the driver angle, it's mostly an issue of getting the position on your head right. I feel the optimum comfort is when the back of the pad touches the back of my ear, but I really can't figure out why AT would do away with the angled drivers when they were so ******* awesome to begin with. I may be looking to put a little padding in the rear of the pads to increase comfort, but I'm worries this will dampen and muddy the sound too much.
Overall, I would say that these are a very good buy. And one strength is that it doesn't take the veteran audiophile to hear the differences here. Even a casual user can easily tell the changes between the AD900, the AD700, and HD 595 without jumping between them. At $200 I feel they are a steal, and even if you dislike the particular sound signature, you won't be disappointed in the purchase like you would for other cans. They have a sound that works very well for certain genres of music, they're relatively inexpensive, easy to drive, and even if you are a basshead they may fill a niche in your lineup that you didn't know you had before.