The Japanese Cult Headphone: Sony MDR-CD900ST

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.

4.5/5 - (36 votes)


  • Reply March 12, 2011


    Hello! For a while now I’ve been trying to find a closed headphone with etymotic’s sound signature and a 50mm driver, which is difficult to find in any price range, let alone $200.

    I used to own the Bluetooth ety8’s till I returned them because the ipod dock stopped working (which I regret) so I remember the etymotic sound very vividly -I really loved their ability to sound so different from recording to recording.

    I’m basically choosing between these and the Audio-technica a900. The soundstage on the AT’s is supposed to be incredible but those phones seem to be too colored/not transparent enough.

    You already said they sound spacious, but how is the soundstage size-width/imaging/detail in comparison to the a900?

    Since I’m coming from the Klipsch Image S4 IEM, a 20 year old MDR-E434 earbud given to me as a gift and the MDR-V6 there detail and transparency should amaze me. XD I’m not interested in a 50mm headphone with sound like the image S4 -Denon D2000- as such an hp would crush my skull lol.

    Also, A member of headfi also described their treble as bright but rolled off, that won’t make the treble sound recessed will it?

    Last but not least, what DAC/AMP can you recommend within 100-200 dollars for these?

    As the CD900ST are still available at for 250$ (online only) I’d really like someone’s opinion on them before I make a purchase, and while head-fi is quite useful for tracking down information, I find your reviews and comments quite honest 🙂

    Sorry for the length.

    • Reply March 14, 2011


      I think the way I described the CD900ST would’ve made it sound a little like the ER4 (my reference for the Etymotic sound is the ER4), but truth is, both are still quite different in their own way. It’s probably safest to get another Etymotic, as that’ll guarantee you’ll get the same sound that you love about the ety8. A lot of Etymotic fans still stand by the ER4, even after the JH13/16, and I do think that there is something about the Ety sound that’s still irreplaceable.

      Of course, if you are interested in the CD900ST, you’re welcome to try it out. I think the CD900ST and the ER4 appeals to the same kind of people, though with their own differences.

      I’ve never heard the A900, and so I can’t comment on it, but I think it’s supposed to be a very different headphone than the CD900ST, or the Etymotics. Something like the SRH840 or the HD200 Sennheiser would give you a closer sound to the CD900ST.

      Rolled off is not necessarily recessed. Recessed is when you find the frequency to sound “sucked out”. Rolled off is when the frequency doesn’t extend as linearly and as far as it should’ve been.
      It’s possible that the CD900ST be a little rolled off, I think the SRH-840 has better treble extension than the CD900ST.

      Ultimately, I think the CD900ST may have had a bit of a high hype factor. It’s a nice headphone, but I don’t think it’s as “ultimate” as some people have made the CD900ST to sound. I find the SRH-840 to be better on all aspects when compared to the CD900ST. After all, one is fairly old driver technology, while the other is a very recent release by a major microphone company.

      I think you should just get an ER4.

      • Reply March 16, 2011



        Thanks! I find how far Etymotic was ahead of its time to be quite amazing, actually; considering the ER4 has been around for over 20 years.

        That leads to some quick questions though, between the ER4-P and ER4-S; which should I get? Etymotic offers an upgrade cable with resistors in it that boost the ER4-P’s impedance and drops its sensitivity to match the ER4-S. As the P and S have the same drivers inside this makes complete sense however, the cable costs 65 dollars and isn’t available as of now.

        The P’s are probably closer to the Ety8 sound sig and having P + cable would make them good for most genres. (A flat eq would bring out the mids)

        If I ignore the cable altogether, and just get the ER4-S, would the Fiio E7 do it justice with its DAC/AMP combo? (I’m already assuming my Fiio E5+realtek soundcard would not)

        If I could find an alternate cable I would be completely willing to upgrade my current setup (Fiio E5+realtek) to the aforementioned setup (ER4-P+upgrade cable+Fiio E7); it would be my dream setup for many years to come lol.

        Also just wondering if I have this correct, BA phone drivers don’t have any break in time right?

        • Reply March 16, 2011


          @Jason, from Headfonia (not Headphonia)

          I wasn’t aware that the ER4 has been around for 20 years? Is it really that long? Wow, where have I been all these time?

          I’ve owned the ER4P and ER4S many2 times. Owned the APureSound cable too, even tried driving the ER4 balanced from the Beta22.

          The ER4S ultimately has the better treble than the P, but the sound is also thinner, slightly less body on the mids and lows. For most people, the ER4P version is good enough representation of the Etymotic sound without having to bear with the thinner sounding ER4S.

          Using the impedance adaptor (I built mine, DIY) virtually gives identical sound as with an original ER4S. I really can’t tell the difference between a true ER4S and an ER4P + 75 ohm adaptor in a blind test.

          One more thing to mention is that the Etymotic HF5 has an identical sound to the ER4P, while often sold for significantly cheaper. I had both at one time and couldn’t differentiate between the sound of the two models.

          I think you need a better amp than the E5 or E7 for these though. Budget some $200 and you can get a good amp from Meier or Ibasso.

          BA phone drivers don’t have any break in time. Correct. People say the cables need breaking in. Whatever they want to believe I guess.

          • Reply March 16, 2011



            The Etymotic HF5 sounds the same as the ER4P? Wow that translates to only a $95 purchase from JR for the HF5 in ruby color.

            How is imaging between ER4P/HF5 and ER4S?

            I mentioned the E7 because of its DAC as I find it would be much better than a built-in realtek card, even out of my Fujitsu umpc which probably uses minimum interconnects.

            My desktop Dell has the same realtek as my umpc, and while the Dell powers my speakers better, quality through headphones is noticeably better out of the fujitsu; but not without eq’ing, as both are quite muddy throughout the entire frequency range.

            On both computers I have the “Environment” setting to “Carpeted Hallway” and the “Equalizer” set to “Soft” with Fubar set to play that. As this lowers bass levels quite a bit, the E5’s bass boost function brings low frequencies back to normal.

            For $100-200, what is the best DAC/AMP I can find? Perhaps a HeadRoom model?

            If the imaging on the ER4P/HF5 is the same as the ER4S I think I’ll take you up on that advice, thanks.

            At least I’ll have decent enough components to power my next earphone interests to save for in the coming years; the Yuin OK1 and EarSonics SM3 lol.

            • Reply March 16, 2011


              The HF5 supposedly has the same drivers as the ER4, with maybe some differences on tolerance settings. I compared both and found no difference in the sound. I’ve been recommending it to people looking for an ER4, since HF5 are much cheaper.

              Imaging is pretty much identical. It’s the same driver version between the ER4P/S and HF5, so you’ll hear the same imaging characteristics. The ER4S is of course better, but again, depending on your ears’ preference, you may find it too thin sounding. The ER4P/HF5 is generally the safer choice. But the difference is only 75 ohms, so you can get the HF5, plug in a 75 ohms adaptor and get the same sound as an ER4S.

              For $100-$200, I’ve been recommending the Audinst HUD MX1 ($180) and the Yulong U100 ($220). The Yulong is better, but with the ER4 sound, I think the Audinst have a better synergy in terms of sound.

              The Headroom models should be good too, but I have not had much chance to do a depth review on their stuff.

              SM3 sounds nothing like the Ety sound. It’s closer to a UM3X. So far I haven’t find one person who enjoys both the SM3/UM3X sig and the Ety sig. So they’re quite opposing signatures. It’s like a Beyer vs Sennheiser sound.


              • Reply March 17, 2011

                Jason Suarez


                I’m the same person that asked about the ety’s, I just decided to log in, sort of as a thank you/more personal gesture after all the help Mike.

                My birthday is June 27 and I’ll be in Spain at that time so my uncle sent me a gift in the mail early; the Fiio E7. Although I probably should have checked your review first, I decided to open it up and give it a try.

                It sounds more refined than what I’m used to. Bass is ridiculous and vocals become really weighty at the cost of air. But its sound sig is dark, smoothed out and laid-back sounding, with lost tightness in tom drums and details veiled behind said dark sound. It’s technically better than my current setup but isn’t lively/engaging enough IMHO.

                I read your review between the Audinst HUD-mx1 and Yulong U100 and enjoyed it. However, I prefer an airy, brighter, wider sound over greater depth/deepness.
                The opamp you mentioned in the Yulong review -Burr Brown OPA627 – only goes for $10 on ebay so I was just wondering if there was a more expensive one that would lessen the gap between the Yulong a little more. Or would the Yulong work out? I get the feeling HF5 needs a wide soundstage or else the Etymotic sound would congest a little. If you think the OPA627 is good enough I’ll buy it alongside the Audinst. Thanks

                • Reply March 18, 2011


                  Hi Jason, thanks for writing.

                  You describe the Fiio sound very well, I think even better than what I wrote on the review.

                  Are you already using the Ety? Between the Yulong and the Audinst, I think the Yulong will give you the sound closer to what you are looking for. More air, less dark, better soundstage, better bass articulation. But one that I am not sure will work well is the ER4 has a forward upper mid, and the Yulong also tend to do the same thing in the mids. With some laidback recording, this can work well to give intimacy, but on forward recordings, I am afraid the vocals may have a little too much presence, even making them honky.

                  Unfortunately I don’t have an ER4 at the moment, so I can’t test this out for you.

                  If you go for the Audinst, instead of the OPA627, go for the AD8066 or AD797. I think it will give you a more open sound but less mid body than the 627. I will have to check if the Audinst’s supply voltage is compatible with the AD797 or the AD8066 though.

                  I will get back to you on that.

                  • Reply March 18, 2011

                    Jason Suarez


                    I don’t have the Ety yet, I just remember from when I compared the Ety8 to the S4 that while rhythm guitars usually mapped as if they were being played on the tips of my ears with the klipsch, with the 8’s they seemed to be placed… closer to the cheek?

                    I actually tested the Fiio E7 on the three different headphones I mentioned; the S4 (Dynamic IEMs)/E434 (old sony earbuds from the same series as the more hyped E484)/and classic Sony V-6 for about 6 hours.

                    I didn’t mention it because I wanted to keep the comment short, but the E7 made the klipsch unlistenable.

                    The E7 made the E434 sound almost perfect as it fixed the faults of those headphones, without too strongly adding the characteristics I mentioned before. The E7 also rounded out/darkened guitar bite that was meant to be in recordings though.

                    As the E7 and V6 both share a forward upper mid, I think I know what you’re talking about, but only slightly. By honky do you mean vocals have too much power and not enough sweetness?

                    You make it seem like the Yulong’s superiority makes up for the slight synergy difference. Truthfully speaking, I don’t think the Audinst’s synergy means as much when you put the Audinst’s lesser detail retrieval into perspective.

                    And while you said the Audinst is wider you didn’t say the Yulong was narrow in any way. Soundstage width and mid forwardness tend to be very perspective so I think that I would enjoy the HF5 with the Yulong more.
                    The brighter sound of the Yulong with their greater detail and touch of warmth in the mids should be perfect. And if it isn’t I can always sell it on Head-fi and make enough back to buy the Audinst and a proper opamp upgrade.

                    • March 18, 2011


                      Lol… I didn’t quite get the majority Ety8/S4/E434/V6 comparison as I’ve never heard ANY of them. 🙂

                      But it seems that you’ve made up your mind about the Yulong, and so I think you should just go for it. After all, nothing beats having the unit at your home and spending time with it.


                    • March 18, 2011

                      Jason Suarez

                      ah, basicly the klipsch have big bass body and edgy treble that lacks detail.

                      The E434 sound like tiny AD700’s with fuller, perfectly placed mids.

                      V6 is a bright, mostly balanced closed headphone with forward upper mids.

                      I was searching around. Where is a good place to buy the Yulong U100 from?

                    • March 18, 2011


                      Thanks for those one liner descriptions. That really helps!

                      Well, I got the U100 from Jeffrey at Have you checked his store? You can click on the link to get to his online store.

  • Reply February 17, 2013



    just a quick heads-up: there is no known model designated ‘MDR-5607’. Perhaps ‘MDR-7506’ is what the author meant? This appears in the first and second paragraphs.

    Thank you for covering one of the more esoteric and harder-to-locate headphones out there.

  • Reply April 20, 2015


    Its the same price as the new JVC SZ1000 beat… What do you think… the Sony or the JVC?

    • Reply April 21, 2015


      According to reviews, the JVC is a bass-monster, while the Sony is mids-oriented or neutral.

  • Reply September 28, 2017


    I wonder how it compares to their studio IEMs, the EX800ST (MDR-7550 in U.S.) There is a website which shows them as a pair:

    and a PDF about their design:

  • Reply October 1, 2017


    they are the work of different designers and it shows, cd900st is rather clinical, like a better balanced 7506, with little subbass to speak of and a forward upper mid, the ex800 is more musically involving with (still) some of the best linear bass – from sub to upper, for iems, regardless of price. it has a very shallow U shape and a slightly peaky mid treble.

  • Reply October 16, 2017


    Typo in the first paragraph? You said the MDR-5607 but I think you meant 7506 unless I’m mistaken. Just thought I would point that out. Cheers!

  • Reply March 30, 2018


    You can also listen the Headphones with the dedicated amp BTL 900 from Japan. I like it mixed with a grace design as a DAC

  • Reply April 6, 2018

    Wayne Fontana

    The Shure SRH-840 lacks sub bass when contouring transient reverb in mastering but it’s still a good studio producer hp. Using just say Cubase or Izoptope for most modern genres of music like Chillstep, nEurofunk, ambient drum & bass etc.. you need the Sony MDR-V6 or its true heir to the throne, the Audio Technica ATH-M50x. The Shure’s are like the Yamaha HS8 studio monitors whereas the V6 or M50x are more like the JBL 308. I’d have no issues using the Shure with a Telecaster but with an 8 string ESP you really want the v6 or m50x.

  • Reply April 3, 2019


    Just a quick comment, tried and owned most akg for monitoring purpose and using genelec high end speakers for mixing, but when it comes to listening music and mixing these headphones are really spectaculars, haven’t tried the super high end brands cause the money, but i’m already trying to buy more of theses before they are gone..

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