Home Closed Back Headphone Reviews Sony MDR-CD900ST Review: Mixing Superiority Over The 7506?

Sony MDR-CD900ST Review: Mixing Superiority Over The 7506?

by Stuart Charles Black
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Greetings mate and Welcome aboard!

Stuart Charles here, HomeStudioBasics.com helping YOU make sound decisions, so…

I finally got my hands on the coveted MDR-CD900ST; an ever-elusive headphone that has made waves in the audio community for its balanced, neutral profile and lasting appeal in the overseas market. 

Is it actually balanced though? How does it compare with the venerable MDR-7506 and V6? Is the CD900ST good for mixing?

We’ll answer all of these questions and more in this comprehensive review and comparison.

So grab a snack, sit back, and relax…

You’ve Come To The Right Place!

Despite the MDR-7506 being the most popular out of the 3, the CD900ST is certainly worth a thorough examination.

Made in Japan, it was originally built for producers in East Asia following the success of the original MDR-CD900 in 1986.

The “ST” in its successor stands for Studio, and this updated version included a redesign of the voice coil and housing structure, eventually hitting the market in 1988.

That’s right, Sony specifically made these for a certain demographic of peeps, and it’s evident in the way they sound.

More on that in a bit.

Beginning with the build, the 900ST is very similar in stature to the V6 and 7506, donning the same headband, bale structure, metal adjustments (numbered 0-11), non-detachable cable, and overall aesthetic.

Despite a nearly identical appearance, there are some marked differences.

For one, the 900ST is narrower and does not fold up, but the cups do rotate a little east to west ensuring flexibility on your melon.


Like the others, you can rotate them completely south as well.



7506 folded

In addition to that, the cups are around the same size in diameter but aren’t as thick and thus a bit shallower.

So your ears are closer to the drivers and this may cause some irritation after about an hour or so.

The same faux leather outfit makes another appearance, but I’m not a huge fan of this material, as it will peel and crack over time; and how soon this happens depends entirely on how often they’re used.



If you plan on listening daily for many hours, expect the pads to start flaking and peeling after about a year or so.

The underside of the headband also suffers from this issue, so bear that in mind.

The 900ST, like the 7506 and V6, is marketed as a Circumaural headphone but functions more like a cross between Supra-Aural (On-ear) and Circumaural (Around-ear).

That is to say that they kind of sit on your ears and around them if that makes sense.

Like the V6, the 900ST displays “For Digital” on the sides of the earcups – this is in stark contrast to the “For Professional” moniker of the 7506.

The overall text on the 900ST is a bit larger, but all 3 contain Sony’s iconic logo and “Dynamic Stereo Headphones”, in addition to their name: i.e. MDR-7506, MDR-CD900ST, and MDR-V6.

The words “Studio Monitor” in hollowed font make another appearance, this time adorned in Gold instead of Silver.


As mentioned earlier, the 900ST is indeed made in Japan while both my 7506 and V6 are “Made In Thailand.”

Lastly, all 3 cables are non-detachable but the 900ST is a straight variety and terminates in a silver 1/4″ (6.35mm) jack at the business end while both the 7506 and V6s are 3.5mm and come with a 1/4″ adapter; the 7506 being gold vs. silver for the V6.





I’ve never found the V6 or 7506 particularly comfortable, but the 900ST is a slight upgrade due to its lighter frame and less intrusive clamping force.

Still, you’ll probably find yourself adjusting them after about an hour or so due to the shallow cups.

They tend to heat up as they dig into your ears and can even cause a bit of moisture over extended listening and mixing sessions.

This is likely why the material slowly degrades, as it’s an extremely thin, overly malleable piece of faux leather covering the foam inside, and thus not all that durable. 

I’ve called for Sony to update the MDR series for quite some time, as the age and outdatedness of all 3 is starting to rear its ugly head.


That said, the sound of the 900ST presents a somewhat stark contrast to both the 7506 and V6. 

If you thought those headphones were neutral, the 900ST is like, “Hold my beer.”

It’s not exactly flat (rather think of an upside-down U), with a rolled-off sub-bass and subdued treble.

The mid-bass is handled beautifully, and because there are no weird bumps or peaks, the texture and vividness of notes come through with good accuracy.

I wish to God all companies who bloat this region of 100-200Hz would get the damn memo and stop doing it, but I’m not going on an extended rant today.

The presence region around 3kHz gets a much-needed rise, and overall, the headphones are fairly balanced across the frequency spectrum – all things considered.

There is a subtle decline from 1-2kHz, similar to HIFIMAN’s house sound, so the headphones can sad slightly wooly at times, but it’s not going to make or break the experience.

This is blank stare city all the way.

In other words, no lipstick on no pigs. What you hear is exactly how the track was recorded.

One thing you’ll notice immediately is that music may sound pretty bad through these.

You may initially blame this on the headphones until you realize that a lot of people just mix music poorly – purposefully or otherwise.

The Lo-Fi genre is famous for being just that; low fidelity, but that’s a can of worms for another day.

In many ways, the 900ST reminds me of my Yamaha HS7, in that it’s brutally honest and transparent in the way it handles sound.

This is most certainly a good thing.

When switching back and forth between the 7506 and 900ST, you can immediately hear the mid-bass emphasis on the former, and to be quite honest, it’s a bit jarring.

Some may be taken aback by the lack of reach and extension below around 70Hz, and it’s understandable.

But unless you plan to mix a lot of sub-bass, I think the 900ST handles the entirety of the low-end well for the most part. You’ll still be able to hear quite a lot going on, it just won’t be as prominent as the rest of the frequencies.


Speaking of, the mid-range is likely the 900ST’s best attribute, which is great news since the mids are arguably the most important to get right in a mix.

As mentioned previously, the upper mids around 3-3.5kHz get a rise, which gives vocals and instruments clarity without going overboard like an alcoholic on a cruise ship.

The low mid-range (roughly 250Hz – 500Hz) and mid-range (2-4kHz) are also very flat and don’t suffer from any strange peaks or dips; another great sign.

The treble is fairly laid back, and while some will inevitably complain about a lack of sparkle, there’s not a hint of sibilance and you’ll be able to listen for long periods without fatigue.

Contrast this with the V6 and 7506; both of which are headphones that suffer from some bite and essiness up top.

Dealbreakers? Not in my mind, but your mileage may vary.

All in all, the 900ST is probably not something you’ll likely want for casual listening, but that also depends. And I’m not talkin’ about your Grandpa’s diapers.

What I’m SAYIN’, is that if you prefer this type of sound for general music listening, the CD900ST is for you. If you’re a producer and need a closed-back, the 900ST is probably better for mixing than a 7506.

And I say that as someone whose first real headphone was a 7506 way back in the day; one I used to mix some of my very first beats on. 

The 900ST is going to provide a flatter, more accurate portrayal of what’s going on, and for a closed back, this is especially important since, unfortunately, you still aren’t getting a very open image or spacious Soundstage.

No, the 900ST is fairly in your head for the most part and isn’t going to wow you in any way – like say, a K702 would.

But, it also entirely depends on what you’re listening to as well, as different types of recordings can yield different results.

One song may not have been recorded in such a way to give off the illusion of a grand Soundstage, but another may have. This goes for shows like Rugrats as well. Through the 900ST, you can hear quite a lot going on in the background, and the image does feel very open.

I would say the headphones work well for most genres given they’re pretty neutral-ish, but if you listen to harder stuff like hip-hop, EDM, etc. and you prefer a lot of slam, you may be disappointed here.

That said, if you’re into mid-range focused music, vocals, the delicate hum of instruments, folk, acoustic, classical, jazz, beats, (should I go on?) you’ll love these.  instruments and vocals sound especially sumptuous, and if you want to get intimate, listen to Mark Mothersbaugh’s Rugrats score in addition to watching the show with these on. It’s a revelation in every sense of the word.

Suddenly all the sounds and ambiance you missed years before come galloping through like a thousand horses, and it’s really something to behold.


They also don’t require much in the way of amplification to get pumping loud enough.

At 63 Ohm Impedance and 106dB Sensitivity, you’ll hardly need any power at all, and just about anything is going to work wonders.

Please, for the love of all things holy, do not overthink this. Read my ethos first.

I happen to mix using a Universal Audio Volt 2/HS7/whatever headphones I feel like when swapping back and forth, but I also have a disgusting amount of amps and dacs here that I review.

Any one of them will do, pig.

Final Verdict

Sony’s MDR-CD900ST is a well-tuned headphone with decent resolution and separation. Soundstage can be hit and miss, the bass rolls off quite a bit, and the lack of sparkle is certainly going to bother some people.

Isolation is decent, but the hybrid character of these (cross between Circumaural/Supra-Aural) means comfort isn’t the greatest over long listening sessions.

All that said, if you can handle its caveats, the 900ST will absolutely net you a better mixdown than the majority of consumer products out there, and, due to its transparency alone, makes a perfect complement to a set of studio monitors like the Yamaha HS7 and an open back like the K702.

Learn More:


Can I say I’m definitively keeping them? Absolutely. They’ll also be added to the best headphones for mixing, mastering, and music production, so definitely check that article out as well.

Well, that’s about it for today my friend! I hope you’ve enjoyed this Sony MDR-CD900ST Review and came away with some valuable insight.

If you love what I do here and want to support the blog and channel in a more personal way, check me out on Patreon and discover all the value I have to offer you.

Questions? Comments? Requests? Did I miss the mark on something? Please let me know down below or Contact me!!

What are your thoughts on this unit? The industry as a whole? I would love to hear from you. Until next time…

All the best and God Bless,





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