PRO 900. The Acoustic Majesty of Professional Grandeur. The first Ultrasone PRO headphones with the...

Ultrasone PRO 900

  • PRO 900. The Acoustic Majesty of Professional Grandeur. The first Ultrasone PRO headphones with the patented S-Logic PLUS technology. Enjoy unlimited sound performance. Trust your ears. New Titanium drivers S-Logic PLUS technology Ultra Soft detachable Cable Diamond-cut Aluminium nameplate Velvet earpds in BLACK & SILVER Hard sided transportation case Neutrik connectors. Short description Foldable, closed-back professional headphones with new Aluminium nameplates New PRO Box (hardcase) for safe transportation and storage, incl. accessories Technologies: S-Logic� Natural Surround Sound MU Metal shielding (ULE-technology) Safer hearing PRO Box contents Professional headphones 2 detachable cables: one straight (length 3 m), one coiled (length > 3 m) with gold- plated jacks 6,3 mm and gold-plated adapter 6,3/3,5 mm Spare pair of speed-switch ear pads Demo CD Instruction manual Technical specifications S-Logic� Natural Surround Sound Dynamic principle Frequency range 8-35.000 Hz Impedance 40 Ohm Sound pressure level 94 dB MU Metal bufferboard, reduced field emissions in accordance with ULE (=Ultra Low Emission) standard Driver 40 mm titanium-plated Weight 295 g (without cord) Long-term availability of spare parts.

Recent Reviews

  1. TWerk
    The EDM master
    Written by TWerk
    Published Jan 2, 2015
    Pros - Powerful bass, Impact, Speed, Imaging, Detail, Comfort, Unbelievable with EDM
    Cons - Can be bright in the treble at times, Mids aren't the greatest
    I've owned this headphone for years, and I cannot say that about any other headphone. I've compared it to headphones costing multiple times its cost, other "supposed" EDM cans, and other Ultrasone headphones.
    The Pro 900 is special. It's the bass, which goes very deep, very low, and sounds powerful. This headphone also has some very good impact, slamming nice and hard on electro house tracks. The bass goes deep, but it doesn't sound too uncontrolled or boomy. This is the best bass I've heard in a headphone.
    Okay, so it has great bass. What else?
    These also have great detail. If you've never heard Ultrasones before, it's a safe bet you will hear things in your music you haven't heard before with their extended highs and very clear sound.
    Now the mids. They a bit recessed. Even though this is true, it is obvious... If you're going to boost the low end and the high end, the middle part is going to sound less "boosted". The mids are still very detailed, just not emphasized much in the overall sound signature. That's okay. You don't need very forward mids for EDM. 
    They are great with anything modern. Pop music, dance music, hip hop, anything with a modern beat which can take advantage of the amazing bass of these headphones.
    These are very comfortable. As the pads break in, they soften. The pad on top is very comfortable as well. I can wear them for hours with no problems at all. I actually love their design.
    Furthermore, these are built like tanks. You'd have to try really hard to damage these. 
    Positioning? You want the back of your ears just grazing the back of the ear pads. That's what works for me, at least. It's effortless to get a good fit, once you adjust the size to fit your head comfortably.
    These have nice imaging when you get them positioned right. You can hear sounds from lower left, upper right, etc. It's a very interesting experience and something I have found the Ultrasones to excel at versus other brands I have tried.
    I think that's about it. These headphones have given me probably 1,000's of hours of listening enjoyment. I love them. Though they aren't perfect, they offer a unique sound signature that no one else seems to offer. And if you love it like me, that makes them very special. Highest recommendations if you are an EDM listener.
    Don't hesitate to add a comment if you love your 900's like me, or if you have any comments or questions!
    These can be run without an amp, and they'll sound great. Most of the time I don't even bother using a separate amp, since they sound great without it.
    Feel free to PM me if you have any questions or want to talk about the best headphones for electronic music (ahem the Ultrasone pro 900)!
    These aren't perfect headphones, but for my listening purposes, they are as close as perfect as I have found, which to me, means they deserve a full 5 stars.
      tbritton, trellus and Renzuken like this.
    1. MadMusicJunkie
      I'm looking at the Pro 900i. It looks like the ear cup has a 3.5mm connection (right?) with screw threads.  Would I be able to use any cable that terminates at a 3.5mm?  I have cable with microphone for my iPhone that I'd like to use with it...
      Also, how would these compare to the Fidelio X1/X2? 
      Thanks for your help.  I too, am an electronic music junky; big time.  
      MadMusicJunkie, Jan 7, 2017
  2. jbarr1989
    One of my favorite headphones
    Written by jbarr1989
    Published Apr 9, 2013
    Pros - Great bass and treble
    Cons - Slightly recessed midrange, sounds can "bleed" a little, especially at high volumes
    I've had these for a couple of years now (although they don't get as much playing time anymore) so I figured I'd write a review.  Of all of the headphones I have owned these are the ones that wowed me the most upon my first listen.  The bass on these is just ridiculous.  They are easily driven by an iPod/Phone but do sound a good bit better when paired with a nice amp.  Like many others have said these do best with electronic music, or anything aggressive, however I have found that they perform more than adequately with all genres of music.  They are a very clean and sharp sounding headphone.  My main complaint about these would be comfort, they clamp very tightly and it can get uncomfortable after a while.
    1. Oregonian
      My thought are these are THE basshead phone but don't get the recognition simply because they are pretty darn good all around. I think they are truly great phones and I have no issues with the treble shrillness some people do. These are in my top two headphones and that's in some pretty select company.
      Oregonian, Jun 5, 2013
    2. jbarr1989
      I definitely agree with your comment. The bass these headphones create is just absurd, but they are imo excellent all-around headphones. I even think they do quite well with classical and acoustic music, pretty much any genre. I have to say I feel that they offer the single best performance for the price out of any headphone I have tried, including the He-400s (which to my ears sound almost as good). I just slightly prefer the D7000s and Th-900s over these, but by a very, very small margin.
      jbarr1989, Aug 10, 2013
  3. jibzilla
    awesome headphone for electronic
    Written by jibzilla
    Published Apr 8, 2013
    Pros - great midbass, detail and speed
    Cons - burnin is long
    worth well more than what you pay for them. need a long burnin though
    1. twiceboss
      how the sounds improve after burned in?
      twiceboss, Mar 3, 2016
  4. LordOctron
    Written by LordOctron
    Published Mar 31, 2013
    Pros - Capable to deliver awesome bass / Comfortable / Detachable cable / Straigt and coiled cable / Two pairs of velour pads / Slick look
    Cons - Way too strong on the lows out of the box / Perhaps not so good for music with vocals
    This cans are able to deliver outstanding lows, but to sound good they need some EQ tweaking imo... I ended up lowering the region between 50 and 150 Hz and slightly raising the region around 2 and 10 kHz. I mainly use em for electronic music, that's where they shine and probably beat most other headphones out there. For other stuff like Rock, Metal or Classic I didn't enjoyed em that much, the mid/low region feels "anomalous" here, hard to describe.
    I find em very comfy, just like my Beyers, velour pads FTW!
    If they were 100 bucks cheaper I'd give em 4 1/2 stars and recommend em to anyone who likes Electro/Dubstep/Drum&Base etc. But for what they cost I only recommend to get em if other "basshead" cans (like the HFi580 or DT770Pro80) are not enough for you :wink:
  5. Monir
    The true meaning of a love and hate relationship
    Written by Monir
    Published Jan 26, 2013
    Pros - incredible mid-bass, detail, build quality, isolation, soundstage, comfort, engaging
    Cons - sibilance, too bright sometimes, unforgiving of low quality recordings, the holographic soundstage, comfort (a little clamping for some heads)
    One of the best headphones for gaming and movies - superb for EDM and dubstep

    Source 1: Asus Xonar Essence ST (OPA2170 + JRC2114)
    Source 2: Audio-gd NFB-3.32
    Cables: Signal Cable Analog II and stock coiled Neutrik 3,6mm
    Amplifier 1: Matrix M-Stage (with LM4562)
    Amplifier 2: Violectric V200

    Music played:
    Skrillex, Knife Party, Netsky, Adventure Club, M83, Infected Mushroom
    Florence and the Machine
    Foster the People
    Depeche Mode
    (All the tracks were FLAC/ALAC 16bit 44.1kHz and 48kHz with ~1000kbps)

    The Design
    The Ultrasone PRO 900 have very robust / sturdy and have a beautiful silvery/metal-like finish to it on the sides of the phones. The general build quality seems very solid and it wouldn't amaze me if this thing could take a lot of beating and survive. They're also a bit heavier than your average headphones, depending on your model of course. Other closed headphones could be a bit heavy, but open cans are generally very light in comparison to these. They're also designed to be portable, probably a really good thing for DJing? You can fold the phones up to the rim and if you have deep pockets they can fit in there, otherwise you have a neat little bag that's included. Changing earpads is also easy peasy, you just rotate/screw them gently to either side and they come right off. Putting new earpads on is just as simple, just press them in where they fit with the bent edges (just like placing a square or a star into one of those boxes for babies) and then rotate them on so they lock.
    The Comfort
    At first wear they feel odd on the head. Since the headband is fairly bendable there's not necessarily much clamping force, but there's a tad more force on the upper areas of the earpads just above the ears. But after a while this is overlooked and the headphones are pretty comfortable, not really that clamping, and the earpads are softer and a bit more comfortable than the ones on the HD650, but still doesn't beat the comfort of the DT990. Overall I would say they're comfortable, more than could be expected. But I should add I have a fairly small head - and I could probably see and issue with people who had bigger heads. Earsize could make an impact as well, but unless you have troll-like massive ears I wouldn't be worried. They're about the size of the DT990. Some people have complained about the padding on the rim which feels uncomfortable on their heads. I can feel it sometimes too, but I won't attribute it to the padding but rather the weight of the headphones - they are fairly heavy, noticably heavier than my HD650 and DT990. Atm I feel quite comfortable with them on. They're not clamping and I don't sweat with them on. However, sometimes the weight can be a little straining and fatiguing; that is my only dislike about the comfort of the PRO900.
    Initial impression (Burn-in 1-2h)
    The first hour of burn-in the Ultrasones PRO900 was hideous. I tried it first straight through the HP out on my Xonar Essence ST. As soon as I connected my Little Dot MKIII it became much more bearable. The warm tube amp managed to soften the higher end of the headphones and brought extra thump and depth to the bass, but still, the highs were prominent and on some tracks I felt a terrible sibilance that could not go left unnoticed. At this stage I realized that I will need many more hours of burn-in. At this stage I also played a random trailer in HD called 'Sorcerer and the White Snake'. I'm a huge film buff, but this trailer seemed like a total piece of laughable garbage. But nontheless I was captivated by the sound the PRO900 managed to present that I disregarded the cheesy CGI effects of the movie. The bass was brilliant: deep and detailed, the highs in this case worked well in the trailer and I can see the V-shape working quite good in movies and possibly even games. The soundstage also felt deep, but not necessarily very wide. I wouldn't call it bad, it's good. But going from the DT990s I felt something odd, I think it could be because of 2 things: the intruding bass, and the fact that the headphones are closed designed - but nontheless there was a good soundstage despite it not being very airy/open (I suspect it is the S-Logic in the works). I also took the liberty to listen to a few dubstep tracks. Generally I don't listen to this genre much, but I thought I'd bring some of it in when reviewing the PRO900 since they should excel in this type of electronic music. I have to admit they have much more power and thumping bass when comparing to the DT990s. Some tracks however were very heavy on the highs, there was still noticable thumping in the background, but you could definately feel the texture on these tracks, which you could not on the HD650 for example (the bass wasn't even present on the Sennheiser). Skrillex - Alejandro is not that bass heavy track, but there's a beat in it that I dig, and it was really present and deep on the PRO900, I remember how I kept tapping my foot to just this track, and even though it was just the first hour of burn in and the highs felt at times pretty sibilant, the PRO900 were very enjoyable with this genre. The DT990s were also bright, but softer and with less bass, at least not as deep and punchy as that of the PRO900. I felt the soundstage was more enjoyable on the Beyers.
    ~24h Burn-in: The bass has become more pronounced and emphasized. The highs are slightly, just slightly more defined but still quite sibilant at times. It's less dry, but only by a margin. I believe I will have to wait longer for the final burn-in process to finish. I'm estimating around 100+ hours judging by the other members.
    Burn-in after 24h
    The bass seems to gradually come forth more, and apart from minor detail adjustments I felt more impact from the beats. The highs were a little smoother, but just a little. I can imagine I would need a lot more time to burn these in, I'm expecting around 300 hours considering what other people have said.
    Conclusion: If possible, I would recommend a warm amplifier - but since it's a low impedance headphone you would mostly be restricted to solid state amplifiers, unless you have the money to go for a tube amplifier with an output transformer - or possible a hybrid amp like LD1+ if you find it good sounding. Having a warm source might help also, but only marginally - however I can imagine either the Yulong D18 or Rega DAC having some impact with their rather analogue sound (I have not tried these DACs so my I'm only speculating).
    My gear consisted of rather budget-oriented equipment but in good stuff for the buck. I can imagine the Ultrasones sounding even better on more expensive gear. I recommend these headphones for some electronic music (mostly dubstep). But overall I would classify these headphones as great for movies and games, it brings a new dimension to these medias' sound and make them more immersive than is. A little convenience of these cans is that they're portable: either by using the small neat bag, or by just folding them in - just expect to bring them to a place where the equipment is made to drive them properly. But, portability might not always be a convenience with these cans. Maybe if you wish to take them with to a meet or to a friend's. People have reported that the PRO900 work well with the portable Fiio amps. Just because they have low impedance does not make it easy to drive in my opinion. You have to take into consideration 1) output impedance and high damping factor for better bass response and 2) output power. The M-Stage runs at 5ohm output impedance (which is ideal for 40ohm) and 400mw/60ohm. It does quite well for the PRO900 and its slightly warmer signature is a good compliment to the brightness of the Ultrasones. However I can imagine these headphones pair very well with the Violectric V200.
    Impression after 300h
    I let the headphones play for more than two weeks through the M-Stage and normal to high listening volume (listening only 15 minutes each 2-3h interval). I can attest to the marginal difference in sound (without trying to be affected by brain burn-in). The bass feels fuller and it seems as if the low-end has gotten more body than it used to have. The sibilance however is still a big factor in this - making some tracks less listenable to, but it's not as terrible as it used to be. The op-amp change in M-Stage could factor in on this.
    The Soundstage
    There is definately a discernable holographic soundstage on these headphones despite them being closed. They aren't as airy as the HD650 or DT990, but they do have a sense of width and depth, still. Some people may call it 'fake' or 'unnatural' and to a certain extent I would agree. The best I can compare this type of soundstage, most likely a bi-product of the S-Logic, is to Dolby Headphone. What it does is that it creates an audible space between the ears and the instruments, making it feel as if the sound is further away from where the drivers actually sit. If you know what Dolby Headphone with Virtual Surround sounds like then you can expect a similar effect from the PRO900. Though its effect is probably just half of what Dolby Headphone produces, which is good news for you who don't like DH. I find this ideal for HD movies and gaming, especially if you have Dolby Headphone enable when using the Ultrasones.

    This is an important factor to closed headphones, mostly because you don't want any sound leakage for others to hear, but also to help prevent you from being disturbed from outside noise - it also contributes to the bass response, as you may be aware of. When I wear them I barely hear much from my surroundings: I have a mechanical keyboard which can make much noise sometimes, especially when I play games or chat. Playing music while typing is no issue, but I can still hear the keyboard if I stop the music. Also, when people speak I usually have to take off my headphones to hear them clearly. From a 3rd person perspective there was minimal leakage on medium to semi-high volume on bass-heavy tracks.

    This is probably what makes the greatest representation of the PRO900's signature. It's quite deep, very punchy and detailed+controlled. I would say it excels more at mid-bass rather than low-bass. I haven't tried any headphones that do low-bass very well, but I believe the Sony XB-1000 or the XB-700 and the Denons should fit this bill. The bass on these headphones can probably be described best as a built in subwoofer. When the bass hits as deepest (especially with some EQ) on some tracks or movies it literally feels as if the ground is vibrating; as if you have a subwoofer standing on the floor. It's a very interesting sensation, although it's all in your head.
    On music the mid-bass shone. It gave so much texture and quality + quantity to dubstep that I could listen to the genre for hours even though it's not really something I prefer listening to. The impatcful and quick punches worked really well with the treble on most electronic songs (but mostly just dubstep, it don't work so well with most Röyksopp tracks). The sub-bass was also quite good. For example, 'Knife Party - Sleaze ft. Mistajam' was head-shaking and punchy on the PRO900. However, do enjoy this type of mid-bass at its fullest the tracks got to be emphasizing this frequency, I found most of the tracks from Knife Party and Infected Mushrom do this well.

    Another part of the signature, contributing to the V-curve in its frequency chart. Think of it like this: the highs are just as prominent and exaggerated as the bass on these cans. Whether it's a good thing or a bad thing is up to you. Personally I think it's more straight forward and engaging, but it's gone way further than the DT990 - even to the point where you could hear sibilance depending on what song you listen to. Burn-in helps soften the initial peak, but it won't go much further down. Luckily, it does go down after burn-in, unlike the bass which seems to go up after burn-in. Listening to Fleetwood Mac was not a very nice feeling. It was overly bright most of the time, and when the cymbals struck it was really high and screechy. To sum it up, on dubstep and most electronic music I ended up raising the volume for more bass thumping; but on pop and folksong I had to lower the volume due to its excessive amount of sibilance. Röyksopp was a mixed bag. I absolutely loved how the Ultrasones performed on 'The Girl and the Robot' for example, but on other tracks the highs were too umbearable. Same goes for 'Florence and the Machine - All This and Heaven Too' where sibilance was very noticable on the many 'sss'es ontop of it being a female vocalist. Same goes for the cymbals and drumkicks in 'Foster the People - Waste'. Short answer: depending on the source it can become very fatiguing at times, and rather than tapping your foot to the rythm you oftentimes end up taking the headphones off for a break. 'Susumu Hirasawa - Yume no Shima Shinen Kouen' however was by far the worst track for these cans. It was so bad that I felt like pressing two screwdrivers into my ears just to remedy the damage done to my head. These headphones need very specific music! You have neutral cans, you have allrounders, and you have basshead cans, THEN you have the Ultrasones.

    The Sibilance and its Sensitivity
    This is the inconvenience of these headphones. Due to its bump in the higher frequencies the sound can be very sibilant depending on the recording. Florence and the Machine did absolutely not work on the PRO900. Florence has such a bright and loud voice which I love, but on the PRO900 it is something that I hate. The PRO900 is also quite unforgiving of low quality recordings and quickly points out the flaws of your tracks. This could be attributed partly to sibilance but also its sensitivity. I still have some 128kbps to 256kbps songs and the Ultrasone did pronounce how low of quality they are, and it can be very unforgiving. Through the V200, which is generally very silent, the PRO900 made a little noise audible at max volume without extra gain setting. And while listening to some orchestral tracks in FLAC/800kpbs, I noticed some background noise of the instruments and recording room which I had never heard before. May this be a good or bad thing, in any case I wouldn't recommend them with classical and orchestral tracks.

    Not a strong point of the PRO900 as the mids are very recessed, even more so than on the DT990. And consequently it makes some genres of music quite unbearable to listen to, especially Susumu Hirasawa, Fleetwood Mac, Florence and the Machine or Depeche Mode; that is when my HD650 shines. In comparison PRO900 sound hollow.

    I think an amplifier in general is important overall for hi-fi headphones, but more so for Ultrasone PRO900. I tried three different amps in this case, gradually stepping one in the price range and quality and sound signature. The first contender was the built-in headphone amplifier in Asus Xonar Essence ST which runs at around 11ohm output impedance and can drive headphones up to 600ohm - it did a good job driving my DT990. But how does it go up with PRO900? So-so. The most think that I found was lacking was the bass, the treble was too overwhelming. Of course I could counter this somewhat with some equilizing - but without damping factor in motion I could hardly get to the PRO900s true signature - and the treble still peaked the bass on bass-heavy tracks. As soon as I switched to the Matrix M-Stage everything seemed so much better! The ouput impedance is at 5ohm on the M-Stage which is a perfect suit for the 40ohm on the Ultrasones - plus the LM4562 op-amp added a warm coloration over the stock op-amp that went really great with countering the treble-peak of the Ultrasones; it also added a thin extra layer of bass quantity. And this time I felt that the bass was more emphasized than the highs but not only that... they felt fuller now and powerful and not as thin and metallic as they did through the sound card. In my opinion the M-Stage is a perfect match for these cans at this price range. Now, can the Ultrasone PRO900 get any better? These are things that I've heard, but since I no longer own the Burson HA-160 I could not try it out. Although, I have tried it on the V200 and found that its grainy treble was 'tamed' by the smoothness of the Violectric. However, the treble will always be there (maybe less sibilant on greater/coloured amplifiers), but not so much if you compare its use on cheaper amps. I don't honestly think it's a true musical or detailed/analytical audiophile headphone, but it's still very fun (maybe hateful and unforgiving sometimes) and very engaging. Other amplifiers I do believe work well with the PRO900 are Burson HA-160 and Yulong Sabre A18 since they share similar character as the V200, but maybe even more so, at least the Burson HA-160.

    In other areas

    Brilliant headphones for FPS gaming, I'd say. Battlefield 3, Counter Strike, Metro2033, Skyrim felt much more immersive and engaging. Especially with its S-Logic holographic soundstage and deep lively bass. Explosions never felt more powerful and real when shooting from a tank or having a grenade explode some yards away from you. And the shouts never felt as overwhelming and authoritive in Skyrim as with the PRO900 (especially in the intro theme: you can literally feel the choir reverberate in your head). And in this case I really think the V-curve sound of these headphones work really well! It might just be my personal preference but I would generally prefer games to emphasize the highs first and low-end to mid bass. Bass would attribute to the more immersive sound of explosions and gunshots for example, while the highs apply to voices and detail to footsteps etc. I have used my HD650 when gaming as well and felt them less engaging and alive than my PRO900 simply because of its emphasize on midrage and weaker bass. Of course they feel slightly more airy/spacious as they are of open design, but other than that I don't feel the same vibe in games I get with the PRO900. The only issue I had with these cans in gaming were possibly in games like Crysis. Because of the extreme highs the voices over the radio were very shrill and annoying. I also mentioned that explosions and shouts seemed very powerful - to a degree it is true, but the gunshots were more prominent as these cans emphasize mid-bass. For more rumble I'd suggest a pair of cans that has deeper bass extension and does low-bass really well. The PRO900 does it well in fact, but its strength lies in mid-bass.

    Ultrasones went really well with movies, especially with the action genre (and its many sub-genres) as it presented a very lively and powerful bass and this semi-artificial soundstage. It sometimes felt as if I was sitting in a room with speakers and a powerful subwoofer pumping on the floor. Similar sensation can be achieved with Dolby Headphone, but I found the Ultrasones working just fine without any DSP. I should also add that when comparing the Ultrasones PRO 900 to the DT990 600ohm in movies (where I would say the DT990 won in terms on soundstage), there was an interesting finding that I made in one scene of the film 'Tower Heist'. It's an indoors scene and you can hear a car drive by outside rather faintly. On the DT990 there was nothing unusual, sounded just as a car should. But on the PRO900, on the other hand, it sounded rather unnatural and impactful; imagine watching 'Transformers' or something with exaggerated electronic/robotic sound with a plentiful amount of raised bass - that's what it sounded like, as if the car's movement affected the door/walls of the building making them 'vibrate'. I kind of like this effect when watching films, but might not be suited for those who want a more natural film watching experience. Of course, I would resort to my HD650 when watching more serious films; the PRO900 will be reserved for shows or commercial (mostly action-packed) movies. The film genre must be very specific when choosing to use the PRO900 respectively the HD650.
    If possible, I would recommend a warm amplifier - but since it's a low impedance headphone you would mostly be restricted to solid state amplifiers, unless you have the money to go for a tube amplifier with an output transformer - or possible a hybrid amp like LD1+ if you find it good sounding. Having a warm source might help also, but only marginally - however I can imagine either the Yulong D18 or Rega DAC having some impact with their rather analogue sound (I have not tried these DACs so my I'm only speculating). The V200 is quite warm sounding, but with detailed highs, perhaps not as emphasized with rolled off highs as perhaps a Burson HA-160, but a good pairing with the PRO900. It smoothes the excessive treble peak and refines the sound even more - especially in the bass department as it bolsters a great bass extension.

    I can recommend these headphones for some electronic music (mostly dubstep). But overall I would classify these headphones as great for movies and games, it brings a new dimension to these medias' sound and make them more immersive than is. A little convenience of these cans is that they're portable: either by using the small neat bag, or by just folding them in - just expect to bring them to a place where the equipment is made to drive them properly. But, portability might not always be a convenience with these cans. Maybe if you wish to take them with to a meet or to a friend's. People have reported that the PRO900 work well with the portable Fiio amps. They're not hard to drive, but I can imagine you'd want a considerably altered sound in your amp when using these ultra-bright, ultra-bassy headphones. I switch between both my HD650 and PRO900 from time to time but generally it looks like this, usagewise: Music + Films (less intense and more acting, scenic) for my HD650, and Games + Films (intense, action-packed) for my PRO900 (with perhaps the exception for EDM and dubstep when listening to Music). These two headphones are so dynamic in that they have so many differences in both strengths and weaknesses that sometimes I would recommend people to own at least 2 pairs of headphones - instead of focusing on just one pair as allrounders for all your sound oriented activity. Even if music is your primary (or only) activity then one type of headphone could perhaps not be enough unless we're speaking expensive orthodynamics and you're on a tight budget already. Think of whatever activity you value the most, or what music genre you listen to the most. If you listen to a lot of EDM, Dubstep, etc. then the Ultrasone PRO 900 is one of the best headphones for this kind of listening - they offer that umph that headphones like HD650 lack (or open headphones in general) and yes even the DT990s. Don't get me wrong, I loved the DT990s, but the electronic music I felt they worked well with felt quite restricting, tracks that the PRO900 nailed it in felt less intense and engaging on the DT990.

      trellus likes this.
    1. ayaflo
      (without trying to be affected by brain burn-in)... how did you achieve that ?
      ayaflo, Jan 26, 2013
    2. Monir
      taking notes, going back to other headphones, and only listening briefly after a few hours of intervals on the same tracks to see if anything changed from the previous listening session
      Monir, Jan 26, 2013
  6. LazBro123
    Excellent Headphones!
    Written by LazBro123
    Published Dec 29, 2012
    Pros - Deep impactful bass, great soundstage, extremely detailed highs and mids, comfortable, look great, detachable cable, efficient
    Cons - Recessed mids, not the most portable, leak quite a bit of sound, highs can get a bit extreme at times, HIGHLY recommend an amp (Fiio E11)
    These are some excellent bass-head headphones. The sound is extremely clear, with an extremely tight, deep, well-textured and impactful bass, a clear midrange, and a very detailed high end. The mids are recessed, so if you don't like a V shaped frequency curve, then steer clear from the PRO 900. The highs can get a bit extreme at times, but I wouldn't call it harsh or piercing... I actually find it quite enjoyable. As well, the soundstage is excellent for a closed headphone, and the lows, mids and highs are all seperated very well. The PRO 900 are also very comfortable imo, and can wear these for hours, because of the soft velour padding. They look great, with the all black matte finish and the aluminium ear cups. Even though these headphones are efficient, I HIGHLY recommend an amp, such as an FiiO E11, which will drive them more than fine. Also, the PRO 900 are not the most portable, as they are pretty darn big. Overall, excellent headphones which I wholeheartedly recommend.
  7. conquerator2
    Revisited - good but not great
    Written by conquerator2
    Published Nov 10, 2012
    Pros - - great build quality - good accessories - good comfort [for some] - easy amping - rap/hip-hop master - great thumpy bass - awesome for gaming
    Cons - - overly expensive - strident vocals - shrill treble- recessed midrange - shallow earpads [for some]
    Ultrasone Pro 900 - Ultimate Review w/ pictures
    1)Equipment and cabling
    Ultrasone PRO 900
    Type: Closed, over-ear, big, dynamic driver monitor
    Frequency response: 6 - 42.000 Hz
    Impedance: 40 Ω
    Efficiency: 96 dB
    Weight: 295 g (without cable)
    Fun, colored, bass heavy, unforgiving, aggressive, extended, V shaped.
    The midrange is recessed with very potent bass and extended aggressive highs. Prone to sibilance, but can provide a very special sound signature. Takes a lot of time to get used to and has a long burn in process. Adds a bit of extra bass to everything. They complement neutral headphones very well.
    Works really well for gaming. Also really good when traveling [even unamped] but a slightly warm amp [ex. Fiiio E11 works really well] would be recommended.
    Doesn't cope well with neutral amps.
    b)Amplifiers, Digital to Analog Converters, Preamplifiers and more
    Fiio E11
    A very versatile little amp.
    Slightly warmer tonality with smooth highs. Decent instrument separation and soundstage. Ideal for most portable headphones. Fits your pocket nicely. The stock[​IMG] battery lasts about 8 hours.
    Packs lots of power. For 60 bucks it is hard to beat. Fully aluminium casing (like all amps here). Has a bass boost switch as well as a low/high gain one. Fiio is getting very popular among audiophiles these days because it offers[​IMG] good quality throughout for the price. The E11 is no exception
    + Small
    + Decent battery life
    + Price
    + Works with most headphones
    - Cannot charge while playing
    Overall 9/10
    [A/N - The amplifier was not tested with the IEM, though I imagine it'd work well together. Not that it is necessary though, as these are pretty sensitive and don't really require amping to sound great]
    Pro 900 stock[​IMG] 1/8 cable
    Very sturdy stuff but also somewhat flexible
    Also comes with a 1/4 cable
    It is coiled. I also think those huge 1/4s are really pretty [much more than the 1/8s] as they feel more audiophile.
    You can also get a 1.2m straight cable for portable use if you want [sold separately] 
    2)Unboxing and accessories
    It comes in your standard packaging. Card-box, manual, a sample CD, the two cables, an extra pair of earpads and of course the headphone.
    Nothing fancy but all the accessories you need are included. The cables are good, the earpads are soft the CD is a nice touch too.
    If all headphones came like that, I'd be happy.
    But as we know, some headphones come in a more bare-bones package, so kudos to Ultrasone here!
    Package overall 9/10
    Fiio not included.
    3)Design, build quality and comfort
    a)Design/Build quality
    The Pro 900 is build like a tank. I actually had an accidental crash test with these. I accidentally pulled them down from a counter [around 1m in height]. It was absolutely in tact afterwards, as if nothing happened.
    Pros are made entirely of plastic and come in at 280g, very durable, they can certainly take a beating, though the aluminium plates on the cups are prone to scratches. 
    As far as looks go, they look quite intriguing, unique indeed. They are not what I'd call sexy, but interesting looking nonetheless. No mistaking these for other headphones.
    Build overall 9/10 (Build quality 9/10 Design 9/10)
    It is a very comfy headphone. Their lighter nature makes for very comfortable listening. The headband's padding does extort a bit of pressure on the top of one's head. The pads, while a bit shallow, are soft and seal well, one of the better made velour materials. They are also interchangeable, though the Ultrasone's proprietary mounting mechanism makes using third party pads difficult. 
    Comfort overall 8/10
    4)First and further impressions
    First off, the burn-in/brain adjustment period is very long with these. It's important to keep this in mind.
    The highs were initially very strident and metallic, even harsh. Yes they were detailed but at the same time aggressive and during the burn-in period it was really hard to listen to female vocals for instance as these were just very sibilant and unnatural [way too pronounced] and not inviting at all. They smoothed out a bit over time.
    Mids,what mids? No just kidding but the midrange is definitely recessed. String guitars and basically any background instruments are pushed back a great deal. Now, that doesn't mean you can't hear them. Because you can. Just not clearly enough due to the highs and lows taking preference. These did not improve with burn-in unfortunately... But it's their signature after all... A big V-shape.
    In the other hand, bass is the next best thing. Really, it is phenomenal. It can do anything and drop as low as ever. It can do subwoofer bass... somehow.
    In general the bass is very deep, impactful, nicely defined and detailed. It can be very satisfying as it can make the earpads resonate, so no change there.
    Great for movies and video games as it can reproduce every explosion to the deepest note, no roll-off.
    Right, but one's biggest strength can also be its weakness. The bass is not tight and very intrusive. It is more than slightly overpowering.
    It doesn't sound particularly real at times [with drums,etc]. It does the oomph, it is not very audiophile  and the extra oomph masks some texture and definition. Where the bass wants more texture than oomph, you still get more oomph. Nonetheless, the satisfaction factor is great if you crave for the boom 
    More in Sound category.
    First impressions overall 7/10
    I will put a graph here, should anyone be interested :]
    + Incredibly punchy and deep bass
    + Detailed
    + Reproduces both rumble and sub-bass effortlessly
    + Incredibly fun and satisfying
    + Mini subwoofers in your ears
    - Too much of it for certain genres
    Overall 8.5/10 – The bass is very satisfying as stated earlier. There are times when you simply can’t have enough of it. It hits as hard and deep as anything. Perfect for hip hop and such but less so for different genres like rock and others as it can sound quite unnatural and overpowering. Nonetheless, this is a bass-head can and as such it delivers. No matter how much bass, it is reproduced with authority and with detail mostly in tact.
    + Detailed
    + When it’s there it sounds quite nice
    - Most of the time it’s not there
    - Gone for vacation (recessed)
    - Pondered by bass and treble
    - Lots of detail is hidden, even instruments
    Overall 2.5/10 – The midrange is only amazing if you can hear it. If you can’t, it’s hard to judge. It’s amazing just how much of it is missing here. You get plenty of drums and bass and lots of vocals and cymbals but you only hear hints of guitars and pianos.
    It’s V-shaped at it’s finest. The headphone was made like this for the reason of it’s fun signature, but I have to rate the mids as well and because there is very little of them and thus you can only hear little of the overall information that lies there, the rating will be representative of that. A recessed 2 and something.
    + Extended and detailed
    + A hint of air
    + Pleasant (to a certain volume level)
    - Unnatural
    - Too much presence
    - Sibilant and harsh
    Overall 6/10 – for a closed pair of cans, the vocals are nice. They are finely extended with a smidge of air. The problem is the balance between them sounding pleasant and harsh is rather delicate. It’s normal for the whole frequency spectrum to get stronger with volume but the vocals are somewhat pronounced by default due to the V shaped sig. Once you cross a certain level they become hard to tolerate and very tizzy. With most singers the sibilance is there but the amount varies depending on whether the song is bright or dark by default.
    + Detailed
    + Aggressive/exciting
    + Extended
    - Unnatural
    - Fatiguing
    - Cymbals
    Overall 7/10 - The highs sound fine. However, they do are, much like vocals, unnatural and fatiguing. Some call it metallic. Cymbals are an issue of their own, they sound way too emphasized, to the point, where their echo goes through your ears, up to your brain, where it causes a mini sensation [as in seizure] and then darts through your skull. The highs are the vocals in black and white. Cross a certain volume or pair them with the wrong source and you'll be wishing to take them off.
    e)Soundstage/Instrument separation
    + Good soundstage width and depth
    + Colored tonality }alters the soundstage in a "fun" way]
    + Okay instrument separation
    + S-Logic?
    - Not coherent
    - Isn't transparent
    - Not a good all-rounder
    - instrument separation suffers due to V shaped signature
    - S-Logic? 
    Overall 7/10 - It would be really good for a closed can, but the V-shape always ends up ruining the soundstaging. It is really nice that the song has strong bass and prominent treble but too bad I can't hear that guitar in the background or the piano behind it.=. The headphone is not good with many genres where midrange is important. However, it excels in genres like hip hop, rap, electronica and dubstep, where midrange isn't very present. If you listen to these exclusively, perhaps this is the can for you. If you don't, then look elsewhere.
    S-Logic does nothing for me. No enhancements anywhere, nothing different from other headphones... If it is some proprietary technology build into the driver, I sincerely hope it wasn't too expensive.
    f)Recordings sensitivity
    Overall 2/10 - Let me say that Pro 900 is much less forgiving of bad files than any other headphone I've tried. Well to be fair, all headphones with analytic treble do tend to be less forgiving by nature but headphones, where the treble is inherently flawed [like this one], certainly enhance the issue.
    Bright recordings are a nightmare. Vocals are most problematic due to increased sibilance. A little sibilance is okay, this is not.
    It is hard to listen at loud volumes to virtually anything, let alone less stellar songs. Your only hope for loud listening is a warm amp/source or dark recordings.
    My ears did not fancy this. Not cool, Ultrasone, not cool!
    Sound overall 6/10
    This HP provides surprisingly good spatial cues and soundstaging here, where the issues are much less prominent.
    The V-shaped signature is much less apparent than with music.
    The midrange is luckily not too important for immersive gaming.
    Highs are nice and extended and detailed as well, albeit not as airy or natural but still very engaging and less fatiguing.
    The bass is again phenomenal here. It can reproduce the deepest explosions, no matter how deep or rumbly it is, 900 will reproduce it effortlessly
    Pros are definitely very fun sounding and some might actually prefer it to other cans here, like with music.
    In conclusion, the Pro 900 definitely works better with games and movies than it does with music.
    Substantially so
    Gaming overall 8.5/10
    The Pro 900 is also great for portable use. With the Fiio E11 for example [not that you ever have to use the bass boost... but you can :]], which is my go to amp for the Pros. They isolate quite well and if you don't mind their size, put them on and go. Don't mind the people staring at you, just enjoy the music!
    I never really found full-size headphones to be too obtrusive for walking, travelling or commuting, as long as they are driven reasonably by portable sources.
    Portability overall 8/10
    My current portable player [Clip+] not tested with the PRO 900 [Back then it was Ace II -> E11]
    8)Unique trait
    Pro 900 - Bass
    As a whole the bass is their strongest point, very punchy and strong. has nice definition and detail and it can reproduce subwoofer like tones and even give the feeling of pushed air. It can do anything bass. Faithfully or not, it always also adds some extra everywhere. I never had it distort and the balance between quality and quantity is more than fine for suitable applications.
    I know this is somewhat reminiscent of all bass heavy cans but it is not always executed as well as it is here.
    9)Songs and genres
    [see HE-6 Ultimate Review, page 1]
    Again if we evaluate the Pros as an entity, it can fill many gaps except for the all-rounder gap.
    It is great for gaming and likewise nice for portable use. However with regards to music only,you can't listen to everything you have in your collection, without scratching you head. Certain instruments and genres just don't cut it and others might sound unnatural. You are left with a mixed bag in the end. Due to the titanium drivers, there is much longer burn-in than necessary and due to the aggressive sometimes even shrill presentation the brain adjustment is longer as well. You can't do one without the other.
    Chances are, by the time you burn them in, you might be on the verge of selling them, like me, but if you persevere, you will be rewarded.
    They have an edge in the build quality, while not necessarily in the design and looks. Nonetheless, their appearance is definitely unique and the headphone is quite functional. 
    For 500 bucks, you might want to have a HP that can do it all, or perhaps not... Either way, 7.5 is the value here. It is a very decent headphone for various kinds of music, be it at home or outside and they perform quite remarkably when used as a gaming can.
    Overall value 7.5/10
    Titanium drivers - very long burn-in...
    I think the Pro900 is a good headphone of a bit overpriced for its original MSRP. The street price has gone much lower, however, and as such  I think around 300$ it is a much better value than it originally was. It is great for gaming and suffices for portable use as well. It is of course U-shaped and as such it is quite restrictive in which genres it performs well. If you are an Electronica/EDM/Rap/Hip-Hop or a gaming fan, these are the great immersive and involiving headphones for you. If you want an all-rounder, neutral headphone though, I'd look elsewhere.
    Pro 900 final score 7/10
    1. View previous replies...
    2. conquerator2
      No, they don't. Bass remains clean and very punchy. They improve with amping of course.
      conquerator2, Sep 26, 2014
    3. Morph91
      Thanks for the reply. I might make a purchase and use them with my STX. I listen mainly to harder electronic music and i have heard these fit that music better than any other.
      Morph91, Sep 26, 2014
    4. conquerator2
      That they do. The STX should be fine
      conquerator2, Sep 26, 2014
  8. TomodachiF
    Great Headphones
    Written by TomodachiF
    Published Oct 9, 2012
    Pros - Great Bass, Good for Popular Genres such as Pop, Rap,RnB, sparkly highs
    Cons - sibilance on some tracks, midrange is a bit recessed, leak a bit,
    These are my first pairs of audiophile grade headphones. I jumped from crappy ibuds to this. This review will contain some detail but not much.
    Build Quality
    These headphones feel solid out of the box. They are made from hard plastic not cheap plastic but proper plastic. The only compliant I have is the swivel joints can make a bit of sound and is not smooth enough for my liking but I can assure you they are solid.
    I think this is where the headphone lacks a bit. The velour padding on the cup and the headband are pretty soft but I wish the padding would compress a bit more. The clapping force is pretty strong out of the box(btw i have a small head) but they will loosen up over time. I found this problem where if the top headband was not positioned properly it hurts the top part of the head after half an hour, this won't happen if you place your headband properly.
    Sound Quality
    Straight out of the box they sounded better than my ibuds but they didn't WOW me like I expected it to.
    After around 5 hours of burn in.
    WOW. The bass on these headphones are amazing. They are very tight, detailed, impactful and extends well. THe bass is top notch. On dupstep and electronica tracks I feel like i just WANT TO DANCE. The only compliant i have is that they lose some detail down in the sub bass region and on some tracks can be a  bit overpowering.
    As we all know the Pro 900s has a V shaped sounds which mean recessed mids. The midrange on these are recessed compare to the bass and treble but will gradually come out after around 70-90 hours of burn in. They won't end up with a flat response but will help cure the V shape to some extent. The mids are detailed and great sounding. They tend to lean a bit to the warm side, but i wish they could be a bit warm to suit my taste.
    The treble are these headphones are sparkly and detailed. I don't find this headphone harsh at all although on instruments like the xylophone it can have a bit of sibilance. The treble is fairly smooth but will sound grainy on bad recordings.
    Music Genres
    These headpones works great with popular genres such as dupstep, pop, Rnb and such. I love listen to Ne-Yo on this as the bass is strong but not disturbing the vocal and for the first i heard the background singers. These headphone are fast works great with fast bass lines and bass drops on dubstep.
    On genres such as rock, the lack of midrange  might make the headphones feel a bit less energertic on guitars. But these clearly separates the instruments and the vocals and have great positioning.
    On classical genres, the headphones have a great and wide soundstage. The positioning of instruments are fairly accurate though i think these lack a bit of depth in the soundstage.
     I don't feel the surround sound of the s-logic to a great extent(maybe cause i have small ears). I heard that s-logic works for some people but not for others.  To find for information you might want to go on the Ultrasone Pro 900 Appreciation thread.
    Don't listen to low quality tracks on these. These are revealing headphones and will definitely reveal impurities in low quality recordings. I recommend source above 256kps, but if possibly please go for FLAC or 320kps.
     These benefit greatly from a properly amplifier. I using the O2 amp btw. These might be rated at 40ohms but I assure you everything is better when there is proper amplification. With proper amping the bass tightens even more and extends a bit more. The mids are more detailed and overall more clear sounding. The highs extend more as will and will become smoother. 
    Overall I would definitely recommend this headphone if you listen to popular genres and want a fast sound. For other types of music these do great with them but not as good as other headphones in this price range. This headphone is very clear sounding and revealing.
    You can find these in America for around $330USD. It cost me $439 because i purchased it locally in Australia.
    1. View previous replies...
    2. TomodachiF
      For me if i moved my ear to the centre of the cup, the soundstage widens and the mids come out more. If you go too forward it sounds grainy and less refined. If you place your ears to the back of cup the mids gets recessed and the soundstage narrows.
      TomodachiF, Oct 10, 2012
    3. Lorspeaker
      This can absolutely need the get into the phenomenal catergory.
      Lorspeaker, Oct 10, 2012
    4. TomodachiF
      Sadly the J$ pads are no longer available. Probably Kee's mod this headphone when the 2 year warranty goes out.
      TomodachiF, Oct 11, 2012
  9. antimatter
    Love my pro 9's
    Written by antimatter
    Published Sep 21, 2012
    Pros - unreal with techno
    Cons - Hot treble
    Love my pro 9's. Best headphone out there in its price range.
  10. Rath1on
    Perfect for Electronica
    Written by Rath1on
    Published Jul 22, 2012
    Pros - Excellent sound precision, deep impact-full bass, detailed mids and high, excellent build quality
    Cons - Can be tricky to get situated on your ears with S-Logic
    So, this is going to be a more, let's say, “specifically special” review. I'm relatively new to Hi-Fi gear, but I know a decent amount about audio engineering and production. As I was looking into what headphones I wanted to buy, I found out that was a really tough thing to do. I listen to dubstep, per se, along with the similar glitchy electronica variations. But (I'm going to try and say this as least hipster as I can), I listen to really, really underground dubstep. There's mainstream (brostep like 99% of UKF), the leading underground (like Biome, Mala, Burial, etc) which are very “down low style” dubstep, and then there's the songs that nobody knows and are really only found on Soundcloud and scattered on miscellaneous YouTube pages. That's where I find songs I like. And it's a pain in the ass to find good songs, let me tell you. Before this starts sounding pointless, assuming it already doesn't, the music I listen to combines the “down low” of classy dubstep with the “excitement” of more popular dubstep and does so in a very melodic way. The mids and highs are there to create a feeling and the bass shoves that feeling down your throat. So, when I was looking for headphones, I didn't know what would fit my needs.
    As for the “specific” nature of this review, I will be focusing on the style of dubstep I listen to and how well the headphones suit it. With that, the headphones are adjusted or, rather, tweaked for that reason. I have done Kees' mod, but I only put felt pads on the back wall and on the driver plate (I suppose would be what it's called). I tried it out with the cotton pad, but that just killed everything I liked about the bass. I have about 60 hours of burn in on them so far. It's been said before and I'll say it again, these headphones REALLY need a burn in. After the first day, I was about ready to return them. But even after just 60 hours (most people say 200+ for complete burn in) they have improved incomparably much. I will reserve a post under this review to comment in a couple weeks after the burn in is complete. I will be powering these phones with a FiiO E17 being used as a DAC through USB from my PC. And with all that hub-bub out of the way, I'll get started.
    1 week old Ultrasone Pro 900s with approx 60 hours of burn in and the “felt pad” part of Kees' mod.
    Fiio E17 being used as a USB DAC + AMP (+12db gain) (35-42 volume) (0 Treble) (+4 Bass).
    Foobar2000 with WASAPI and flat EQ.
    Songs are 320kbps CBR, 44.1k, 16bit, mp3s.

    Songs being analyzed. (And a little description as to why. I'll go into more detail during the testing)
    Vexare – Clockmaker (bass + mid range emphasis)
    Hulk – To The Stars remix (low low bass + low vibes + vocals)
    Biometrix – Running (bass + wobbly goodness + vocals)
    Mitis – Don't Know (bass + huge mid range sounds + extremely complex background sounds)
    Mitis – Elevation (progressive style bass + high wobbles that drop into low bass very rapidly)
    Mitis – Identity (for being the most beautiful song of all time. And bass)
    Build quality
    These things feel awesome. I wouldn't expect any less from a German manufacturer than to build top quality durability with looks and functionality. They are made of that really good plastic that America, apparently, hasn't yet accepted as being better than metal for such things. The pads are are paddy and stuff (and there's an extra pair). The adjustable-ness of the headband is very solid; it stays where you set it. The removable cable port is strong (which is a really good thing) with no wiggle. So, yeah, they're German. What do you expect?


    This is kind of tricky. They aren't uncomfortable. But, they aren't very comfortable. Due to the circular nature of the cans, there's not really an area where your ears can be so they aren't touching something. And, due to S-Logic, there's only 1 area your ears CAN be so that you're getting the most out of the technology. So, there's quite a bit of adjusting them over and over and being finicky about how they're sitting. Or maybe, I just have a previously unknown OCD regarding circles and ears, I dunno. But, I can usually get the correct placement and just hold them there. I don't wear my glasses while I'm listening to music, so it's not like I have anything else to do but nod my head, close my eyes, and imagine all the decibels are little warriors of the Trojan war trying to break in to my head. Because my name is Troy. :D

    I'll have a mini talk about the different frequency ranges and then I'll have an “overall” summary of them. And then I'll go on to talking about the actual songs I'm testing.
    Lower Mid Range (150hz – 1000hz)
    I like to think of this range as the “perfect sounds” range. These are those dark piano notes that just seem to get you, know what I mean? In any case, this range is very, very important to me. Other than the bass, it's the main part of the song in a lot of the music I have. With the Pro 900s and the E17 (which has a good mid range emphasis), there's just so much detail... so much. Forget anything you've heard about the mids being recessed, I don't know what they were doing wrong. The mid range reaches out and touches you and then falls back into place with graceful pleasure. Piano notes hit strongly and fade away quickly. Wobbles move up and down without any “friction” from interference with frequency change. The range is clear, detailed, quick, and versatile. It stands out from the commotion above it and builds on top of the bass from below it.
    Upper Mid Range (1000hz – 3000hz)
    Normally, these frequencies aren't kept separate from the previous ones, but just keep reading. I'm not going to explain myself while explaining myself. This range marks the end of the “dubstep noises.” Mostly. You don't really see wobbles or heavy frequency modulation sounds past 2khz'ish. And, with filter or pitch LFOs they extend up and down from 3khz to 1khz. The kind of sounds in this range would be the very agitated sounds that old people find disgruntling. But, with the agitated nature of these sounds, they need to have a bit of control. It's more tough to pair bass with the lower mid range, so when there's an emphasis on this range, there's usually some wubwubwub'ing that matches it. Ultrasone must have had me in mind when they made these, because this range has just a little bit of space to it. It's tough to explain, but, along with being incredibly detailed and vibrant, there's also some extra room in there for the bass to come in without disrupting anything.
    High Range (3khz – infinity and beyond)
    Everything past 3khz tend to be the rhythmic bits of the song (hats and claps and snaps and such) and lots of overtones. Overtones errwhere. Upon looking at the frequency response graph for the Pro900s, I got a little worried seeing that they got really happy at 6khz. I don't particularly care for 6khz. We've never liked each other. That said, I don't really notice the spike. I used to notice it, but not anymore. Whether it settled down with the burn in or there's just too much going on below it for me to pay it any attention, I'm not sure. But, the entire high frequency range is relaxingly supportive. “Oh, but Troy, everyone says the highs are super bright and harsh. Get outta town!” (that's how you guys sound to me in my head). Well, yes they are bright. Since the burn in and Kees' mod, they aren't harsh at all, and brightness doesn't have to mean that they stand out over everything. With frequency modulation, there's a lot of importance to overtone quality. I don't want to get really technical here, but if note A at 440hz is a square wave (I love square waves), there's lots of maths and physics going on and it's also producing a note at 1.3khz, 2.2khz, 3.1khz, 3.9khz, 4.8khz, etc. And these are all very important in frequency modulation because you can pick and choose which overtones you want to mess with and do fun things with them. Long story short, the brightness of the Pro900s accents these notes very well. Being overtones, they are paired with lower frequencies, but they don't stand out over them at all. These are sort “side sounds” off of the “real sound” and they are there to add to them in neat ways and that's exactly what they do.
    Upper Low Range (80hz – 150hz)
    I saved the bass for last. This is where the kicks are and some wobbling will occasionally be put in the mix to try and permanently damage your hearing. Other than that, though, this is where the “backbone rhythm” of the song is. Kicks will emphasize a large sub bass coming in along with keeping the rhythm. This range is actually the most boosted part of the phones, as far as the frequency response is concerned. But, here's the thing... there isn't too much of the mid bass. And this is coming from a guy who is a big fan of sub bass. It's actually kind of soft feeling. But impact-full too. Lots of impact with care. It's like a pillow fight with Tempur-Pedics. The bass rolls around really well and noticeable as the size of the bass is awesome. With all the loving care that it boasts, it doesn't intrude on the mid range at all. It stays behind it and plays nice as the backbone that kind of keeps the rest of the song in check.
    Lower Low Range (20hz – 80hz)
    Awwwwww yeahhhhhhhh. Okay. These are not sub-woofer headphones. If you're looking for something that will squeeze your face sideways and be a force of Zeus, the M-Audio Q40s are a nice choice. The Pro900s aren't like that. At first, I wasn't sure what to think about this either. Before these, I was using phones with D2000ish sub bass levels. So, when I popped the Ultrasones on, the first thing I thought was “where's all the damn bass people were talking about?” Oh, it's there. But, it's not a prideful bass. It doesn't want to bully you, it doesn't want to force you to do something you don't like. It wants to help you. Let's see, how can I explain this...? Hmmm... Well, first off, the sub bass part of dubstep is very, very important. There's all the stuffs going on above it creating a song as songs have always been songs. And then, the sub bass comes in and adds a new element or a new sense, if you will. I'll put it this way. Without the sub bass, the rest of the song is playing and creating a feeling or emotion in your mind. With the sub bass, one of your other 4 senses (touch) also comes into play. The song is touching you. Now, both physically and emotionally. Think about that. The short range of frequencies that the sub bass covers has so much meaning to it. With as short as it is, the most needs to be made out of it. We can't just have everything below 60hz being an earthquake. What Ultrasone has done with the bass on the Pro900s is something I have to use metaphors upon metaphors to try and explain. It's a wonderful creation of sound. The depth of the bass is staggering. We all have felt what 30hz feels like, but do you know what 30hz sounds like? It's a deep cry of sadness. The sub bass on the Pro900s has a mind of its own. Don't get me wrong when I said these aren't earthquake sub-woofer headphones, though. There's plenty of push from the sub bass, but it's the sound that's really special. Not just the feel.
    All the Elements Combined
    With all this commotion, you would imagine it may just be too much. And that would make sense. If these weren't engineered by the Germans, that probably would be the case. I think the REAL final piece of these phones is S-Logic. I really do. And you can easily tell by moving the headphones around (or just flip them). As you move them forward, the bass starts to muddy up with itself and the treble and mid range go into hiding. If you move them backward, you're just going to have more treble than you know what to do with and there will be no bass to comfort you. My knowledge of S-Logic is pretty basic but, from my understanding, the groves and cuts in the driver spread out and channel the sound. I imagine that statement doesn't give it justice, but that's the gist of what I get. As opposed to all these sound coming from one place, they are separated by the driver itself and channeled a certain direction. If your ears are in that direction, you are given an amazing sensation of sound. All the frequency ranges seem to compliment one another. I never hear fighting between them and I can always distinguish the sound they are playing. Ultrasone has a wonderful thing going here that, I think, deserves a lot more credit. S-Logic is that final element that allows all the precision boasted on the frequencies to work together in ferocious harmony. It's simply wonderful.
    Vexare – Clockmaker
    The piano in this song is very soft. It is used as a subtle background melody as the detail of the mids really is noticeable. The vibes that make up the drop are always pulling themselves around and dragging out as long notes and sound ever so powerful. They vibes pan left and right a lot and this doesn't take away from anything else. The rest of the sounds are solid in place and what needs to be panned gets panned. The glitchy high notes accent these strong vibes with so much precision and distinction. The crashes are smooth and clear. The mid bass hits and go away with the vibes for superb emphasis. The sub bass fluctuates with the mid range vibes and pushes deep when the size of the vibes really matter. Nothing overpowers anything else and it all sounds so amazing building up together.
    Hulk – To The Stars remix
    The guitar and percussion in the intro is all very quick and lifelike. The singing has the perfect amount of air to it and is very clean but forward. The kicks in this song play a big role and, like before, do a solid job of laying the “foundation” for the sounds they emphasize. The highs that glitch around do so excitedly but be sure to stay above all the other notes to just be for contrast. The drop has some of the most complex wobbles I've heard. They are very grimy, but smooth, but powerful. The Pro900s highlight these wobbles so, so well. They move around flawlessly and make themselves sound important. The bass is always changing to fit the vibe and goes deep when those wobbles really just need to hit you. The singing on top of the drop stays completely clear and doesn't get distorted or overpowered by the bass and all the other noises going. The drops is, all around, very complex and the Pro900s fit all the different sounds together just as they are supposed to.
    Biometrix – Running
    There's a lot going on in that Upper Mid Range here. The singing in this song isn't as natural as To The Stars. It has a bit of computer-ness to it as made by Biometrix. The background bass that comes with a lot of the non drop elements is subtle and stays back. The synth notes are clear and quick. The build up is full of high range frequency changes and isn't ever harsh and sounds far away instead of in front of everything. The drop itself has all the ranges in it. The mid range wobbles are just as smooth as the previous songs and the distinction between them and the big upper mid synths is superb. They don't sound like they affect one another. There's not as much bass in this song as the others. The bass here is used to add depth to those wobbles because those wobbles are supposed to sound intimidating and unavoidable. And that's exactly what happens.
    Mitis – Don't Know
    Mitis' songs are always super duper detailed. And are prone to sibilance. His songs are the only ones I have ever heard high frequency distortion on before. This song was particularly bad on the Pro900s before the burn in and Kees' mod. Now, 60 hours in, I don't have any distortion or sibilance at all. The sounds that were causing them are soft, clear, and detailed. They caused issues because of where they were actually playing. Slight high range glitches on the peaks of bass waves are, I imagine, tricky. But, as I said, the burn in and the mod completely got rid of the issue. Now, the rest of the song is just full of huge sounds. Mitis likes to use House'ish build ups in his dubstep and the Pro900s handle it easily. The constant punchy bass constantly stays punchy and the constantly busy mid range is constantly busy. There's no interruption for a confusion amongst anything and it flows very well detailed. The drop has one of the most powerful sounds in it I've heard. The scream of the 1khz vibe is huge and just encompasses you and makes you think of bad things. Then, it drops away and the upper mid range wobbles come in a just screw up your world with the bass kicking and roaring as the master of it all. It's all so perfect and I don't really have any other way of describing how well the Pro 900s handle such a powerful drop.
    Mitis – Elevation
    Similar to “Don't Know” in it has a progressive house intro and build up. There are a lot of sounds in here and, I'm probably starting to get redundant but, the Pro 900 keeps the sounds detailed and separate and the bass solid. The drop is full of frequency goodness too. It goes from lower mids to upper mids and back down and around and all over with different wobbles and vibes. The bass is introduced with a downward swipe of a vibe between the wobbles and rolls off of it with force and precision. Then it changes its attitude quickly when the wobbles come back and let them do their thing while acting as support. The kick adds that element of management to everything and stays in control without being in your face or too kicky and uncomfortable.
    Mitis – Identity
    110bpm is where's its at. I'm getting into my own production soon and this is where I plan on focusing. It was actually this song that made me realize this is where I most “feel” this kind of music. Mitis is a genius. A professional pianist turned EDM producer. And this song is proof of his genius. I'm going to go into too much specifics of how the Pro900 handles everything. It just does it perfectly as expected, remember that much. The mid range whine takes charge and reaches out for you but doesn't quite get there. The piano plays behind everything while atmospheric elements coat everything. The bass doesn't want to be too pushy as its there for purely for that extra sense of touch and interpretation as the mid range creates the mood. Wrapping this up, the drop boasts quick synths that pop up in front of the rest of the song. They synths are clear and, the whole song is created to perfection by the Pro900s.
    Regarding the E17, Kees's mod, and the burn in.
    I had the E10 before the E17 and, when I got the E17, the different was instantly noticeable. The bass boost on the E10 just didn't sound good. The E17's is much clearer and useful. The E17 seems to be a warmer style amp and it fits perfectly with the Pro900s. The bass and mids are brought to their full potential and the whole frequency range seemed more “at east” than with the E10s. The felt pads on the back smoothed out the effects of the bass, it seems, with the added mass. The felt pads on the driver cover smoothed off the highs and made them appear more natural and relaxed. But, with these 3rd party tweaks, the most important is the burn in. From everything I've read, I'm not even half way through the full burn in and cycle and yet I can tell you, these thing change A LOT. Due to the technicality and precision of it all, it really has to work itself in. At first, the high were really harsh, the bass was muffled, and the mids were too laid back. Just messing around, I set up an EQ to try and see what could be done. I had the bass ranges at like +2db, the mids at +1.5db and from 1khz-10khz I had brought down 1-3dbs depending on where the harshness was. As hours were put on them, these adjustments were brought together into a flat line as they kept becoming more and more balanced.

    This has been a bit long winded, but I really wanted to be thorough in why and how the Pro900s suit EDM. So, to wrap it up quickly, let me just say that these are perfect for dubstep. You can try and take my explanations and see if that's what you're looking for in similar genres, but I really don't see how the Pro900s would be as beneficial to other genres as they are to electronica. The bass is deep, precise, and magnificent. The mid range stands out on its amount of detail and moves around flawlessly with quick pitch and frequency changes. The high range bright enough to not get left behind by the other ranges and just bright enough to play the “outside role” of accenting the lower frequencies.
    Audio quality – 5/5
    Comfort – 4/5
    Design – 5/5
    Value ($335) – 5/5
    Overall – 4.8/5
    Post introduction.
    I hope you guys enjoyed reading this. If you have any questions, comments, or concerns, I'm more than happy to talk and open to criticism. So, feel free. I hope to be spending a lot more time with you guys as I continue my interest with audio and start getting into production myself.
    Links and references.
    My imgur gallery of the phones:
    Mitis' Soundcloud:
    Hulk's Soundcloud:
    Biometrix's Soundcloud:
    Vexare's Soundcloud:
    Take it easy, guys.
    1. View previous replies...
    2. Zoomer13
      As soon as I can manage it, I'll probably be snagging a pair of these, so thanks for the review :D
      Zoomer13, Jul 23, 2012
    3. Rath1on
      :wink: You're welcome. I'm glad it helped someone make a decision. All of teh sounds are belong to me. ALL OF THEM.
      Rath1on, Jul 23, 2012
    4. Lorspeaker
      rereading your review, yaaa...u owned all the frequencies...:p
      whats the next can u are gonna control??
      Lorspeaker, Jul 23, 2012


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