Sony MDR-CD900ST

Disclaimer: I bought this on amazon Japan at my own expense.

Price: paid 125 usd (excluding VAT)

Specifications:

Frequency response: 5-30,000 Hz

Impedance: 63

Max. Input Power: 1,000mW

Accessories:

None



Cable: 2,5-meter-long cable, is pretty thick as most headphone cables are. Does not have a 3.5mm -> 6.35mm, only a 6.35mm connector. Has a strain relief and the connector is pretty big.




Build: Plastic/metal build, is pretty lightweight, slight cup rotation and you can flip them as well. Headband has damping and is pretty comfortable. The headband has a numbered adjustment system, from 0-11 (I am using it at 7), it’s not that long so if you have a big head be aware of that. L/R markings are marked with color on the headband. Be careful to not touch the center part of the cups, as the driver is pretty close to your ear.

Fit: Depending on your ear size, its either fully on-ear, over-ear or a weird “hybrid” fit (which is what I am getting).

Comfort: Bad, the weird on/over-ear fit makes it quite uncomfortable for longer sessions (along with my usual complaint of heat generation).

Isolation: slightly below average, not bad considering the hybrid on/over-ear fit.

Setup: Schiit Asgard 3 (low-gain, volume around 9 o´clock), stock pads, stock cable

Lows: Flat with rolled-off sub-bass, lacking a lot of quantity for my preferences. But has very good texture (especially mid-bass) considering how low quantity it has, is on the tighter/faster side so it is clean. Not for bassheads though, the sub-bass definitely isn’t satisfying for bassheads.

Mid-bass: Metallica – fight fire with fire (01:11-01:52), bass is clean due to the speed and tightness, lacking quantity though but decent texture. The (02:55-03:01) section with the chopper is hearable and pretty clean.

Hiroyuki Sawano – Pretenders (01:18-01:47), low quantity but quite good texture, is clean due to the speed and tightness.

Sub-bass: Djuro – Drop that bass (01:15-01:30), doesn’t rumble nor extend that much. Punch quantity is lacking and texture needs to be higher, is on the tighter/faster side.

Will Sparks – Sick like that (03:08-03:22), quantity is low but good texture, is on the tighter/faster side.

Mids: If you like mids, get this ASAP. Excellent vocal (both male and female, but especially female) tonality, forward, natural timbre and clean, has detail without “cheating” with brightness.

Female-vocals: Hiroyuki Sawano – OldToday (01:25-01:52), excellent vocal tonality and is forward, timbre is very good and is clean and detailed. Instrument tonality is very good, natural timbre and clean/detailed.

Yuki Hayashi – MightU (01:58-02:55), vocal and instrument tonality are excellent, with very good timbre, clean and detailed.

Evanescence – Bring me to life (01:18-01:35), vocal is a bit shouty and fatiguing.

Hiroyuki Sawano – Crescent (02:07-02:26), sharp treble and shouty vocals, very fatiguing.

Male-vocals: Hiroyuki Sawano – Pretenders (00:57-01:17), vocal and instrument tonality are very good, forward vocals and natural timbre, clean and detailed as well.

Hiroyuki Sawano – Scapegoat (00:57-01:17), vocal and instrument tonality is good, although could be a bit warmer, detail is good but clarity could be better.

Treble: Linkin Park – Shadow of the Day (03:24-03:42), electric guitars are a bit sharp and fatiguing but good timbre.

Deuce – America (03:03-03:16), a bit shouty and chaotic.

Hiroyuki Sawano – Lose (string version) (01:22-01:59), Cello tonality, texture and timbre are very good, detailed and clean. Violin tonality is quite good but does lack some brightness, treble-extension could be better, but timbre and detail are good.

Hiroyuki Sawano &Z (02:18-02:57), tonality and timbre are very good, detailed and clean.

Soundstage: Smaller (both width and depth) than average for a headphone (not that bad if you are mostly an iem user though). This is intentional by design though, since it is meant to be used as a monitor.

https://soundchaser.org/the-story-behind-sony-mdr-cd900st-and-its-unique-design-and-tuning-choices/

Tonality: n-shaped (would be neutral if the sub-bass/upper-treble wasn’t rolled-off), very good timbre. Note-weight is balanced between thick and thin, a versatile tuning.

Details: good detail without “cheating” with treble boosting, upper-treble roll-off does bottleneck the micro-details though.

Instrument Separation: separation and imaging are pretty good (it is a monitor, so they definitely need to be up for the job).

Songs that highlight the Headphone: https://www.youtube.com/watch?v=dNGiRuLABgI https://www.youtube.com/watch?v=uj5DRn7Y4ok https://www.youtube.com/watch?v=hNEC1NEfqLA https://www.youtube.com/watch?v=hSzyI3u5DFo

Good genres: The First Take, Hiroyuki Sawano, Acoustic/vocal music

Bad genres: Trance, EDM, Hip-Hop, R&B

Comparisons:

Headphone: Victor HA-MX100V

Bass: Djuro – Drop that bass (01:15-01:30), extends lower and rumbles more on the 900ST. Punch quantity is similar but more textured on the 900ST, similar tightness and speed. More tonally correct and better timbre on the 900ST.

Hiroyuki Sawano – Pretenders (01:18-01:47), a bit more quantity and texture on the 900ST, a bit tighter and faster on the MX100V. Tonality and timbre are a bit better on the 900ST.

Metallica – fight fire with fire (01:11-01:52), a bit cleaner on the MX100V due to the slightly lower bass quantity and faster/tighter bass, more textured on the 900ST and more tonally correct on it though.

Mids: Hiroyuki Sawano – OldToday (01:25-01:52), very similar vocal tonality, but a bit more forward and better timbre on the 900ST, slightly more micro-details on the MX100V but similar macro-details and clarity. Instrument tonality and timbre are better on the 900ST, similar detail and clarity although a bit airier on the MX100V.

Evanescence – Bring me to life (01:18-01:35), more fatiguing treble (brighter) and a bit shoutier on the MX100V.

Hiroyuki Sawano – Scapegoat (00:57-01:17), better vocal and instrument tonality and timbre on the 900ST as well as more forward vocals on it. Similar clarity and macro-detail but more micro-detail on the MX100V.

Treble: Linkin Park – Shadow of the Day (03:24-03:42), electric guitars are a bit more fatiguing on the 900ST but better timbre.

Hiroyuki Sawano – Lose (string version) (01:22-01:59), Cello tonality, timbre and texture are better on the 900ST but a bit cleaner and more detailed on the MX100V. Violin tonality is similar, but better timbre on the 900ST while treble-extension and detail are better on the MX100V.

Hiroyuki Sawano &Z (02:18-02:57), tonality is a bit better on the MX100V and airier treble, but better timbre on the 900ST.

Technicalities: Shiro Sagisu – Hundred years war (02:24-02:57), soundstage width is similar but deeper on the 900ST. Macro-detail, imaging and separation are similar, but better micro-details on the MX100V while timbre is better on the 900ST.

Overall: They are both monitors, both from Japan, both have that “hybrid over/on-ear” fit. But the CD900ST is pretty much dominating everything sound related.



Headphone: Hifiman Sundara (High-Gain), stock pads, stock cable 6.35mm

Bass: Djuro – Drop that bass (01:15-01:30), extends lower on the Sundara but rumbles more on the 900ST. Punch quantity is a bit higher and more textured on the 900ST but much tighter and faster on the Sundara as well as cleaner and more detailed. More tonally correct and better timbre on the 900ST.

Hiroyuki Sawano – Pretenders (01:18-01:47), a bit more quantity on the 900ST and more textured, a lot tighter and faster on the Sundara. More tonally correct and better timbre on the 900ST.

Metallica – fight fire with fire (01:11-01:52), much cleaner and more detailed on the Sundara due to the lower bass quantity and faster/tighter bass, more textured on the 900ST.

Mids: Hiroyuki Sawano – OldToday (01:25-01:52), vocal and instrument tonality and timbre are better on the 900ST but a lot cleaner and more detailed on the Sundara. Similar vocal quantity, although the Sundara is overall a lot more fatiguing.

Evanescence – Bring me to life (01:18-01:35), shoutier and peakier and a lot more fatiguing on the Sundara.

Hiroyuki Sawano – Scapegoat (00:57-01:17), vocal and instrument tonality and timbre are better on the 900ST but a lot cleaner and more detailed on the Sundara.

Treble: Linkin Park – Shadow of the Day (03:24-03:42), electric guitars are a lot sharper and more fatiguing on the Sundara, better timbre on the 900ST.

Hiroyuki Sawano – Lose (string version) (01:22-01:59), Cello tonality, timbre and texture are better on the 900ST but a lot more detailed and cleaner on the Sundara. Violin tonality, treble-extension, detail and clarity are a lot better on the Sundara but better timbre on the 900ST.

Hiroyuki Sawano &Z (02:18-02:57), a bit better tonality on the Sundara and a lot more detailed and cleaner, but better timbre on the 900ST.

Technicalities: Shiro Sagisu – Hundred years war (02:24-02:57), Soundstage is much wider on the Sundara but similar depth. Imaging, separation and detail are a lot better on the Sundara. Better timbre on the 900ST.

Overall: The Sundara is definitely outclassing the 900ST when it comes to technicalities, but the 900ST is tuned better (for my library at least) and has better timbre.



Headphone: Sony MDR-1AM2

Bass: Djuro – Drop that bass (01:15-01:30), extends a bit lower and rumbles a lot more on the 1AM2. Punch quantity is higher on the 1AM2 but more textured, faster and tighter on the 900ST. More tonally correct on the 1AM2 but better timbre on the 900ST.

Hiroyuki Sawano – Pretenders (01:18-01:47), punch quantity is a lot higher on the 1AM2 but is a bit more textured and a lot faster/tighter on the 900ST. A bit more tonally correct on the 1AM2 but better timbre on the 900ST.

Metallica – fight fire with fire (01:11-01:52), cleaner on the 900ST due to the lower bass quantity, faster and tighter bass as well as more textured. (Treble is also peakier on the 1AM2 and more fatiguing.)

Mids: Hiroyuki Sawano – OldToday (01:25-01:52), vocal tonality, timbre and clarity are better on the 900ST similar detail and a bit more forward on the 900ST. Instrument tonality and timbre are a lot better on the 900ST and a bit better detail on it.

Evanescence – Bring me to life (01:18-01:35), shoutier vocals and sharper treble on the 1AM2.

Hiroyuki Sawano – Scapegoat (00:57-01:17), vocal and instrument tonality is better on the 1AM2 but better timbre and cleaner on the 900ST.

Treble: Linkin Park – Shadow of the Day (03:24-03:42), electric guitars are a lot sharper on the 1AM2, better timbre on the 900ST.

Hiroyuki Sawano – Lose (string version) (01:22-01:59), cello tonality is a bit better on the 1AM2 but better texture, timbre and cleaner on the 900ST. Violin tonality and treble-extension are better on the 1AM2 but better timbre and cleaner on the 900ST.

Hiroyuki Sawano &Z (02:18-02:57), a bit better tonality on the 1AM2 but peakier treble, more natural timbre on the 900ST.

Technicalities: Shiro Sagisu – Hundred years war (02:24-02:57), a lot wider and a bit deeper on the 1AM2, more holographic. Imaging and separation are better on the 900ST but similar macro-detail while micro-detail is better on the 1AM2. Better timbre on the 900ST.

Overall: The 900ST is better tuned and has better timbre, they are pretty even when it comes to technicalities where the biggest difference is in the soundstage. 1AM2 is more suited if you prefer something more V-shaped, while the 900ST is the more neutral one.


Conclusion: Excellent tuned and great timbre, technicalities can still keep up with more modern headphones as well (although the stage isn’t that wide but it is intentional). If you are a mid-lover, drop whatever you are doing and get this ASAP.

Reference/test songs:

I bought this headphone last year from a fellow head-fier. Unfortunately one of the channels recently died. I suspect this is a cable issue as it was recabled by the first owner. Eventhough at that time I was already looking for a better closed headphone to replace them, I must say I will regret the CD900ST. This is a very capable headphone for the money.
 
As a studio tool you know what to expect, and the CD900ST does deliver a very well balanced and smooth sound. Unlike many headphones they don't have forward midbass, upper mids or treble. The only other fullsize headphones I've heard that are so well balanced are high end stats (the CD900ST actually reminds me of the Sennheiser HE60). They have an airy quality that can make them brightish and inconsistent sometimes, but they don't have a peaky treble at all. I know there are many conflicted descriptions about its treble, some people call it bright and analytical, while some others call it dark. I don't think these are accurate statements, again the CD900ST is quite flat and has an airy feeling that do make it sound a bit analytical, but not agressive by any mean.
 
The only downside is that you could sometimes wish for more bass quantity. Bass extension is good but bass and low mids are a bit on the light side. As a result tonality is not the most realistic I've heard, and I prefer the darker balance of the Stax SR-007 and SR-003. But if you can get used to it the CD900ST can become a very addictive headphone. It has a very intimate soundstage that sounds super clear and engaging. Female vocals can be breathtaking. Bass has good impact and music always flows in a nice airy way.
 
You should keep in mind that CD900ST is not a giant killer, it's a modest studio headphone, as such it doesn't have extreme resolving capabilities. It's not fast and razor sharp like an electrostat or even like balanced armatures IEMs. But for the money you will hardly find a better portable headphone (it beats the HD25 hands down). Get it recabled and you have a killer portable can. Comfort is quite good for me and weight is ridiculous. I should mention that it's also very easy to drive and and can sound very good out of a cheap Sansa Clip. Warmly recommended.
 
Addendum: I can have my CD900ST repaired as it was only an issue with the jack plug. I'm glad and this headphone is a keeper at the moment... I've had two occasions to audition the Z1000 lately and I was underwhelmed, I consider the CD900ST to be more balanced and clear, and maybe as detailed. The Z1000 can hardly be considered as a studio reference. I also let my Thunderpants go without regret. These were far from neutral and not especially impressive from a technical standpoint (in other words: way overhyped !!). The only thing I really liked about the TPs are soundstage and presence.