Here is an obscure little Sony headphone that we don’t hear too much about. Unlike the MDR-V6 or the MDR-5607 headphone, the Sony MDR-CD900ST is relatively unknown, except perhaps in Japan, where it is quite a popular monitoring headphone.
The build follows the same Sony styling that you see with the MDR-V6 or the MDR-5607. It’s fairly comfortable and lightweight. Despite the closed design, isolation is not that great, much lower than what you get from a Sennheiser HD25-1 or a Shure SRH-840.
The reputation of the Sony MDR-CD900ST for a good monitoring headphone is well deserved. The sound is fairly neutral and uncolored. Though it has a sterile and analytical feel to it, that can be a very appealing if you’re into that kind of headphones. The sounstage is fairly spacious, when compared to other closed headphones in the $200 price range like the HD25-1 and the SRH-840. Due to the analytical sound signature, you really feel that the CD900ST is very revealing of the source. You do get an impression of detail, clarity and transparency. But after longer listening, I actually think that the detail and transparency cannot compete with more expensive cans like the K701 or the HD650.
I had some suspicion that the SRH-840 and the CD900ST was somehow separated at birth. Perhaps the same engineer that worked with Sony later moved to Shure to design the SRH-840. Perhaps the same base driver was used, but tweaked and given a different housing treatment. The Shure sounded remarkably similar to the CD900ST. Even their housing takes the same slanted shape with very similar basic lines. The Shure is like what the new BMW Mini is to the original Mini. It’s like someone took the original CD900ST design and created a newer version that’s bigger and better than the original. The tones, the voicing of the headphone feels like something of the same family. Being a newer product, there were also obvious improvements with the Shure, like the much improved midrange and bass presence, as well as an overall smoother sound from the Shure. The fit, comfort, and isolation is also much better with the Shure.
The CD900ST is certainly unique. I think that this headphone was purposedly designed to sound analytical. The AKG K701 can even sound warm when you put the CD900ST next to it. It definitely doesn’t have a Pop-voice that most Sony headphones are known for. It’s a love it or hate it headphone. It has quite a big following, in fact, that I’ve seen one guy ranks it higher than a Sennheiser Orpheus and a Stax Omega2, and another amplifier manufacturer made a headphone amplifier with a dedicated CD900ST output jack (like the Navigator HPA-900).
While I find it hard to listen to music with the CD900ST due to its analytical and sterile sound, it definitely stood out among the abundance of Pop headphones we find these days.