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REVIEW: Perfect Sound d901 dido> > headphones > > REVIEW: Perfect Sound d901 dido

Friday, November 22nd, 2013

by Warren Chi & Michael Mercer


You've probably never heard of Perfect Sound. Don't worry, you're not out-of-the-loop. While they are already well-known in Asia - particularly in Taiwan where they hail from - they have yet to launch a sizable marketing campaign here in the States. So what makes them stand out amongst the sea of Asian headphones making their way onto our shores?

Their $799 flagship headphone: The d901 dido, is a fashion-conscious, fully metal, closed-back unit that is said to feature bio-cellulose drivers. The same bio-cellulose driver technology pioneered by Fostex, and subsequently used in their high-end headphones: the $1,499 TH600, and the $1,999 TH900. Yeah, we thought that would get your attention. It sure got ours!

"Three things cannot be long hidden: the sun, the moon, and the truth."


Perfect Sound first popped up on our radar nearly eight months ago in March of 2013. And while we were immediately intrigued by the "Fostex" driver rumor, it wasn't until May that we made contact with them at The Headphonium at T.H.E. Show in Newport.

We began our dialog there, and finally asked them point blank whether their headphones use the same bio-cellulose driver technology found in high-end Foster/Fostex headphones. The answer we received was as unexpected as it was definitive:

"Yes. We are confirming this and you will know once you have tried our headphone."

-Perfect Sound

This settled the matter for us, and immediately triggered an intense desire on our part to review the unit.

Appearance, Fit and Finish

Design-wise, the d901 is one part Beats Pro in the hinges, one part vintage Sansui in the ear cups, and one part Kanye West in the padding and upholstery. Now wrap up all of that in a package that's so chromed out the universe can't even handle it. That's the d901 in a nutshell.

While the bulk of it is mirrored chrome and etched metal, the d901 is offered in your choice of two upholstery finishes: black and white leather.

Mercer opted for the white swag version, while I stayed safe with executive black. We have since decided that we're going to swap first chance we get. But regardless of which version you get, the ridiculously-high bling factor is the same.

There is no screen printing of any kind throughout the entire unit. Every logo, functional indicator (L & R) and artistic detail is either laser etched into the unit, or worked into the stamping mold itself.

Visually-speaking, every detail of the d901 is flawless and screams luxe luxe luxe. If we had to select one headphone to include in the gift baskets at the BET Awards, the d901 would be it!

These are for the fellas who gotta look cool while rockin' em. There's absolutely nothing wrong with bling that's done right, done tastefully. With relatively minimal design changes, we could easily envision the d901 sold as a Prada accessory. Simply put, the d901 is the girl on the cover of Maxim: smart, sexy, and ready to fuckin' party.

Build Quality & Construction

Tank. Brick shit house. Insert your own choice of superlative metaphors here. This thing is beyond well-built; beyond solid.

Each and every part of the metal armature is machined to incredibly close tolerances, then meticulously screwed or welded together. In our experience, this makes the d901 very resistant to daily wear and tear as well as our [inadvertent] 1m drop tests.

One of the d901's main features is that it folds up for travel, with its earcup assemblies swiveling upward in the same way that a Beats Pro or Beats Mixr folds.

The d901's implementation of this mechanism performs flawlessly. After an untold number of swivel-tucks, the pivots remain smooth and tight with no signs of being loose in the caboose.

The vertical length adjusters are likewise extremely durable, with very little play or wiggle after hundreds of hours of stress applied. Even the supple leather comfort strap held up well throughout heavy use.

We have no qualms whatsoever awarding it top marks for build quality.

Ergonomics & Comfort

Now, one would imagine an all-metal headband assembly to be hideously uncomfortable. That is not the case here. Perfect Sound seems to have taken this into account, and engineered the headband to have a rather wide arc. This resulted in very little clamping force with which to cause us discomfort.

However, the flipside of this is that the d901 can be loose-fitting at times. Of course, this is largely dependent on the girth of your particular noggin, but Mercer and I found the d901 slightly larger than we would prefer. Still, we're not complaining, as we understand this to be the result of a design compromise.

Just remember that it may be loose for some - perhaps you - and that a loose fit will affect both leakage and isolation as well.

Additional Features

Like Beats Mixrs and Beats Pros, the d901 features dual inputs for either left or right side cable entry. And of course, the unused jack can also be used to daisy chain additional headphones that also feature detachable cables. In fact, Perfect Sound offers an optional 4m (13.12 feet) cable for exactly this purpose.

Unlike Beats Mixrs and Beats Pros, the d901's jacks provide for a very secure cable attachment. Each ear cup features an external catch that is slightly smaller than their cable housings, which are made of a soft and pliable rubber. Once a cable is inserted, it is then "caught" and held firmly in place to reduce the chance of being accidentally unplugged. A somewhat low-tech, but effective solution.

Accessories & Options

The list of included accessories are rather spartan in our opinion. In the d901's gift box packaging, you'll find the headphone, a removable cable and an aluminum stand. That's it. And while that is more than enough to ensure proper operation, we do wish it came with a few more items.

For example, some kind of protective case or bag would have been nice. Since the d901 itself is built like a brick shit house, we're not really worried about mechanical damage. But we are concerned that the d901's polished chrome finish might receive a few scratches over time. A case or bag would go along way towards preventing that.

Speaking of the d901's smooth and lustrous finish: we wouldn't mind a cleaning cloth of some kind. This thing is such a fingerprint magnet - every touch becomes a maddening affront to our delicate (i.e. OCD) sensibilities. A robust cleaning cloth would go a long way towards settling our nerves. Okay, fine, we're being a little vain here. After all, it's all about how the headphones sound right?

After applying a fair amount of burn-in to both our units - via pink noise and regular use - we developed clear and consistent ideas of how the d901 performs: all you basshead audiophiles out there, you can stop dreaming now, your unicorn has landed!


With Daft Punk's "Doin' It Right" and Charles Murdoch's "Why" we found the d901's low-frequency response to be perfectly respectable most of the time - though your mileage may vary depending on how good of a fit and seal you can get.

With a good seal, the sub-bass is well-extended with a good sense of impact. With a poor seal, it can thin out prematurely and lose coherency at times. And in case you are wondering, we found heavy head movement to be the main culprit behind the loss of a good seal.


The d901 is perfect for bassheads who need that visceral slam; the kind of hit you feel deep down in your loins. The sheer amount of slam and energy throughout the mid-bass is stunning, literally. Take the d901 for a romp through Porter Robinson's "Language" or Madeon's "Icarus" and you'll experience what we're on about. The d901 can change your fucking heart rate - no joke.

In fact, these are the only headphones currently in our labs that can cause nausea with their bass assault. They're that potent. They hit harder than a Denon D7000, punch tighter than a Sony XB-500, and can easily make a pair of Beats cry like a little biotch - and that's saying something.

But before you dismiss the d901 as a bloated or muddy mess, you should know that its bass response is also viciously fast and virtually distortion-free. Bass hits - even those in rapid succession - come at you as distinct impacts and not interminable drones. And these hits are clean, with no audible distortion. We confirmed this with Trentem°ller's Remix of R÷yksopp's "What Else Is There?" and Skrillex's remix of Avicii's "Levels." Oh there's probably some low-end distortion in there somewhere, there always is, but you'll most likely have to measure the d901 in order to find it.

Is this a result of the bio-cellulose drivers? Has Perfect Sound instilled the d901 with some of that quick and dynamic bass that Fostex's TH-Series is known for? Who gives a shit. We just decided to just enjoy the bass-kicking we got, because clean bass beat-downs like this are rarer than one might think.

So if you're looking to get drenched in the smooth and sharp edges of the low frequency effects from artists like Eskmo, Nosaj Thing, Machinedrum, Burial, Four Tet or Thievery Corporation... via a Funktion-One-like club experience; the d901 is your VIP pass through the velvet rope.


Don't let all this talk about the bass fool you. While the d901 does have a formidable bass hump, it presents the rest of the audible spectrum as well, albeit in a more polite and reserved manner. Taking a tour through some less bassy tracks, we found ourselves surprised and amused at how well the d901 rendered both the lower and upper mids for us.

The d901's lower mids were lush and full-bodied with The Impressions's "People Get Ready" taking on an organic quality, despite the archival sound of that vintage recording. But the d901 also served up some admirable depth and textural detail in Livingston Taylor's "If I Only Had A Brain", Marvin Gaye's "Sexual Healing" and "Bring It On Home To Me" from The Commitments Soundtrack, Vol. 2. Female vocals were likewise rich and natural in tracks like "The Prayer" by Jonathan & Charlotte and "Icicle" by Tori Amos.

While we're at it, we should mention that the d901 made everything from the Eighties sound better! We weren't sure anything could ever salvage that decade, but the d901 made a good go of it. Banarama's "Cruel Summer" and Wilson Phillips's "Hold On" sounded better than they have in years. What, oh please, don't even give us crap about Wilson Phillips. We know you sing like a little girl on the inside whenever it comes on. OK, maybe not, but with these cans you might.

Moving into the upper mids, we found the d901 impressively controlled in terms of sibilance and stridency without sounding sibilant-proof in a rolled-off kind of way. Breanne Duren's saccharin but sharp vocal work in "Honey and The Bee" by Owl City was listenable without too much irritation. Another Owl City track, "On The Wing" from Ocean Eyes, impressed us by remaining crisp and snappy in the upper mids. The sometimes somber, spacious, and soulful female vocals in Trentemoller's new Lost album were also well-articulated.

So yes, the mids are recessed in comparison to the bass. But they are neither absent nor muddy. You simply get a lesser portion, a smaller entree. Not ideal, but by no means the end of the world. Had they lifted the mids just a little bit more, and delivered it with more velocity and authority, the d901 would have had been more compelling. Shit, it would've been a knock-out!


The d901's mids and highs remain in relative balance to one another. Occasionally, the highs may step out a bit, giving the d901 a U-shaped sound signature at times. But for the most part, the mids and highs take stage in unison.

The highs that are present fall just short of a gossamer airiness, so tracks like John Williams's "Yoda's Theme" are enjoyable, but not exhilarating, because they don't have the sonic fairy dust factor at the top end. In many ways, the d901's highs remind us of a cross between Beyerdynamic's DT770 and DT880, particularly in pop tracks like The Dave Matthews Band's "Crash Into Me" and Fantastic Plastic Machine's "Philter."

Detail & Definition

As long as you're not listening to bass-heavy music, you'll be rewarded with some surprisingly decent detail retrieval, primarily in the mid range. It's not a detail monster, but the d901 maintained good separation of individual elements as well as overall coherency with most tracks. We were able to discern the autoharp in Rosanne Cash's "I Don't Know Why You Don't Want Me" and the sympathetic string vibrations in Sarah Jarosz's "Annabelle Lee" without straining to do so.

We should also note that the d901 excels at presenting detail naturally, with a creamy smoothness that is neither irritating nor offensive. This allowed us to enjoy the harmonies within Ride's "Crown of Creation" as separate vocals, as well as a sum of those parts. The same was true with Radiohead's "Everything in it's Right Place" off Kid A. The synths and vocals rippled forward with silky smoothness, but weren't so rounded off that everything got muddied. The presence was intact.

Soundstage & Imaging

Staging is balanced along both axes (width and depth) and lies just on the cusp of being out of head in many a track, which is rather good for a pair of closed cans. Live recordings, like "Wild Mountainside" by The Trash Can Sinatras, performed well enough to keep us engrossed in the music.

There's even a hint of Y-axis (vertical) placement with well-mannered recordings like Chesky Records's "What You Don't Know [Live]" by Sara K. The d901's imaging prowess is exceptionally good for all but a few tracks - like Yanni's "Swept Away (Live)" - which exhibited a bit of rushed left-right panning; though Mercer refuses to admit any listening sessions involving Yanni whatsoever.


If you're into balance and neutrality, you've probably figured out that the d901 isn't your cup of tea. But if you're a basshead (or closet basshead) this might just be the one you've been searching for all your life.

We don't offer up this statement merely because of it's ass-kicking low end thump and high bling factor. The d901, unlike most bass-heavy cans, also draws you into the emotive power of the music. So many headphones with staggering bass sound technically adept, but lack soul. They're captivating because of the shear velocity and volume of the sounds assaulting your eardrums. Your brain gets over-loaded.

With the d901, its massive bass fluidity doesn't muck up the rest of the audible spectrum. That's an accomplishment that makes for fascinating listening. You get the oomph and the finesse of your music, albeit a tilt towards the slam. If this sounds like something that'll move ya we recommend checking it out immediately. We're certainly not parting with ours!

The Perfect Sound d901 dido is now available in the U.S. at Moon Audio:


Ear Coupling: Circumaural
Driver Type: Dynamic
Driver Diameter: 1.57 inches (40mm)
Impedance @ 1kHz: 16 Ohms
Weight: 13.93 ounces (395 grams)
Connector Type: 1/8-inch (3.5 mm)
Cord Length: 4.26 feet (1.3 meters)
MSRP (US): $799

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