My first real headphone experience was with a pair of Grado SR60s which I still own to this day. All I knew at the time was that they were "audiophile" quality, and I truly thought that this must be the pinnacle of headphones. It wasn't until a few years ago that I discovered Head-Fi and the amazing depth that this hobby has. As I read more and more, I realized my beloved SR60s were only the ENTRY level of headphone heaven. I then relocated to Santa Fe, NM, and got to experience a few more headphones. A buddy at work let me use his pair of AKG 240Ms. What a truly different sound it was to my Grados. This is what really sparked my interest in wanting to experience different models, and my taste for headphone audio began to develop. I also got the chance to try out the Sennheiser HD 265, as well as the Sony MDR-V6. Both of these were horrible to my ears, the Grado and AKGs were far superior. I moved back to NC, and soon decided to get serious with this headphone business. I scanned every manufacturer's website, and only one model really held my interest: The Beyerdynamic DT 880. Those earpads looked WAY too inviting to pass up. By this time, I had also learned I'd need a headphone amp to be able to drive them properly.
Before headphones, I had been exposed to many high end speakers and amplifiers(mainly Cary Audio amps), and was lucky enough to have a friend that worked at Cary Audio Design(and designed the acclaimed CAD-500T amplifier, as well as the A5). I knew he was the guy to ask for a headphone amp. I wanted a warm, rich, but accurate amplifier to go along with my 880s, as this was the sound I liked. He decided on a very simple circuit. I had the option to go with Black Gate output coupling capacitors if I wanted to. I decided to go with them, hoping they'd justify the difference in cost. The outcome was great, it was worth the extra bucks . This is the amplifier used in this review.
My sources are a modified Pioneer DV-414 with a LM833 opamp & Muse caps, a modified Pioneer DV-578A with Black Gate caps, and a modified Sonica. I also have 2 modified Marantz players, but I've always felt they have a slight harsh edge to them. For those concerned, I used Radio Shack Gold ICs, and "regular" power cables. I've tried expensive ICs before, and found hardly any difference between them audibly. I've also experimented with using power filtering, and found no difference as well.
The Test --
I have owned my DT 880s since October 2003, and have enjoyed them immensely along with my Sony MDR-CD1700s and Grado SR60s. I also owned a pair of Sennheiser HD 560s, which I sold to a board member awhile back. After hearing my DT 880s, my brother became more and more interested in headphones, and decided to get a pair of DT 660s and DT 990 Pros from HeadRoom. They've gone through a decent burn-in, and I found each to benefit well from it. All of my opinions are AFTER burn-in.
I used a few different well-recorded CDs for my comparison:
Erich Kunzel - Time Warp(Telarc)
R Kelly - R
Phenomenon Movie Soundtrack
Lusine - Serial Hodgepodge
Chris Cornell - Euphoria Morning
DT 660 --
Part of a new lineup from Beyerdynamic, the DT 660s were the only closed model introduced. The grills give off the appearance of them being open. They are surprisingly heavy, and seem very well built along with the DT 880 and DT 990. The earcups are much shallower than the 880/990 design as well. The headband has a small section of cushion at the top. It's fairly comfortable, but can drag your hair up if you re-position the headphones(if you have hair). The cable is 3m long, and is straight. The connection to the headphones is sturdy. The headphones do fold up, but the space saved is minimal. It's easiest to extend the headband to the longest length, then fold them upwards. The earcups also swivel 90 degrees just like Grado models. Wearing comfort overall is good, but the earpads can get rather hot after extended sessions. Speaking of earpads, the retail box also contained a set of pleather pads in addition to the cloth ones installed, but I haven't tried them out yet. These aren't the most comfortable to wear for extended periods, but they don't become extremely annoying like, for instance, Grados do.
My first impression of the DT 660s was positive. To start off, the high end was very clean and accurate. They definitely have an emphasis here, no doubts about that. Depending on the equipment used, they could even be called strident. Even still, nothing was offensive. The detail is superb without being analytical. This is fairly tough to pull off, but these do it gracefully.
The midrange, and especially upper midrange, is classic Beyer. It shares the same tonal balance that the others do, and is very pleasing to listen to. Detail, again, in this range is excellent. Voices, both male and female, are very articulate and natural. Male voices don't have quite the weight they should, though. Guitar notes have a good balance, which I find can sound too detailed and unnatural in some phones, or smeared in others. They perform very well with acoustic and classical recordings. Unfortunately, not ALL is good..
The low end was a disappointment for me. The upper lows quickly drop off, and this continues to get worse the lower you go. They sound restrained, and almost empty. Detail was also lacking, and I felt most of the low end gave off that "one-note" sound. I was hoping burn-in would help in this area, and it did to some extent, but not nearly enough. This to me is the huge critical flaw of these phones, it's so disappointing. You get the feeling the drivers are just trying to produce the bass, but it just comes out as being muffled, and again, restrained. Also, the lack of "uumph" in this area detracts from the mids, making them sound a bit prominent. This is definitely the Achilles' Heel of the DT 660s.
I was very interested to see how large(or small) the soundstage was on this model. From the closed phones I've heard, it's hard to get anywhere near the soundstage an open phone can produce. The DT 660s muster up a fairly wide stage for a closed phone, but there is a definite limit. The imaging is superb which helps you forget you're wearing closed phones to some extent. You can get a fairly involving experience when listening to an active stereo mix.
DT 990 Pro --
I've been really interested in trying a pair of DT 990s for quite awhile. The reviews I've read indicate they're similar to the DT 880s, but with more bass and perhaps a little darker sound. This piqued my curiosity. The first thing I noticed was that they LOOK like an old headphone, and they have been around for quite a while. The earpads are the same as the DT 880, as well as the headband. A problem with the DT 880 I had was with the headband burning my scalp after long listening sessions(others have reported the same). I tried removing the rubber piece inside the headband, and the scalp burn went away. This piece is absent on the 990s, which is great. I guess I have a large head, because I found fitting the DT 990s to be a pain. I extended the earcups all the way down, and I still had to tilt the headband forward a bit to get the right fit. The non-pro edition of this model I believe has the same (longer) headband as the DT 880 as well as less clamping force. The DT 990s clamp fairly tight, but they're not uncomfortable at all. It felt good to have a secure fit to be honest, sometimes I find the DT 880s to be a bit loose.
I couldn't help but smile when I put these on. The sparkling highs, the thunderous bass, it's wonderful! The high end is lacking in detail when compared to the DT 660 and 880, however. Not terribly so though, they never sound dull. The highest octaves are sparkly, which gives the sound a nice flair and excitement. They really do sound great, but not neutral. The lower highs can sound slightly rolled off, which brings us into the mids.
There is a slight dark overtone to the midrange. Again, nothing extraordinary, but noticeable. Male vocals have tons of weight and power behind them, and female vocals sing nicely(though perhaps not as nice as the DT 880s). The Beyer signature is slightly shadowed here, but the tonal balance still remains the same as the others. They all hit the same spots similarly in the midrange, and I love it. Everything flows nicely through these phones, I haven't yet discovered a recording I didn't enjoy.
I was so impressed by the bass of the DT 990s my jaw just hit the floor. It's not that I haven't heard bassy phones before, but the level of control and precision displayed is unbelievable. On some recordings, it can be overwhelming in some spots, but in most cases this is not the case at all. I've seriously never heard bass this musical before. It's not neutral, there's a good amount of emphasis here, and it can occasionally overshadow the already dark midrange.
Soundstaging is overall very similar to the DT 880, but I feel the channels sound a bit too "separate." Imaging was just shy of the DT 880s performance, but still impressive. They're very involving, and only add to the fun factor.
DT 880 --
These were my first high end phones, and I've found no reason to go any higher than these. Refer to the above comparisons on the DT 990 for my comfort impressions.
Compared to the others, the DT 880s are neutral. Almost every note hits perfectly where it should. The detail present is amazing, and nothing is emphasized. That being said, they can sound at times(depending on mood really) a bit boring. Everything is so clean and accurate that they can sort of force you to critique the audio instead of enjoying the music. This is really nitpicking, because in the end it's up to the person on how they listen to headphones.
The only thing I want to highlight in the midrange are female vocals. I'm not quite sure what it is, but they sound so incredibly magical and smooth. Every nuance of this frequency range is reproduced to perfection. I don't know if this is "neutral" or not, but it sure is natural sounding.
Another point I want to bring up is that some feel the DT 880 is lacking in bass or there's emphasis placed on the treble. I disagree with both. The bass is controlled, powerful, and neutral. It doesn't have the "boom" of other phones because this isn't natural OR neutral. The response extends extremely deep, again, in a controlled and powerful manner. The only slight nitpick I have about them is that the soundstage can sometimes hide or mask tiny details present in a recording. But really, this can give the music a "deeper" soundstage and more natural feel.
The DT 660s would do better in a darker sounding system. They do have their place in the headphone world, but they're really not for me. The only disappointment, albeit a big one, is the low end. Anyone looking for an accentuated or neutral bass response will be ultimately disappointed. One thing I didn't mention before is that they do isolate pretty well. Loud noises can leak in, but ambient noise is completely shut out. Hardly any sound leaks to the outside world. Anyone looking for a light sounding, easy to listen to headphone will enjoy them.
The DT 990s and 880s are a good match. The DT 990s are so involving, and so much fun to listen to. All kinds of music sounds fantastic, and you can't help but nod your head and/or tap your foot. They are proof that you don't have to sacrifice lots of detail, tonal balance, or accuracy in order to have a fun sounding phone. The DT 880s are, in my opinion, completely neutral. I don't detect any emphasis on any frequency range, the detail level is astounding, and the soundstage is immersive. I can see myself using the DT 990s when I just want to jam to my music, and using the DT 880s when I want to study and evaluate the music(and the equipment).
All in all I'm very happy I got to try out all these headphones. Beyerdynamic is a great headphone manufacturer, and what's really amazing to me is that they all have very different personalities. I find I'm most compatible with their "house" sound, and it makes me want to try out some of the other models.
I hope this review was easy to read, and most importantly, helpful to anyone looking for an opinion on these headphones. I have provided links throughout the introduction and to the headphone models in case anyone isn't familiar with the ones mentioned. Comments, critiques, and suggestions welcome.