Beyerdynamic T51i


It’s hard to find the T51 anything but engaging and fun, without taking too seriously as a critical listening device. The first thing I noticed about the T51’s sound was just how rich and involved the bass was. The second thing I noticed was how smooth it is in general, with some patented Beyer sizzle up top for some high end energy without being overwhelming. It fits my genres of music near perfectly. Genres like Trance, Chillstep, and Trip Hop are all produced with great authority on the T51.

I’m a recovering, early day bass-head, though I’m not a neutral-head in any sort of way whatsoever. I like my bass present, potent, but natural enough to not take away from the mids. So, slight bass emphasis in general without being too potent.

The bass is the meat and potatoes of the T51’s overall sonic flavor. It goes quite deep, and with convincing authority. The bass has copious amounts of presence between 35hz-45hz (while still being respectably audible at 30hz). Many headphones don’t tend to hit that low, instead choosing to roll off quite a bit beyond that and focusing on higher bass notes, causing some deeper sounding tracks to miss the atmospheric rumble which I feel to be absolute necessary. The T51’s deep bass resonates in an agreeable and natural way to my ears.

The mid bass is in full effect without it being overly aggresive or tactile. Not the best in texture and definition, but I personally like some softness and decay in my bass, which I feel is done quite tastefully here. It isn’t far above the lower bass, though it certainly takes precedence over the lower mids in terms of emphasis. The mid bass control isn’t super tight, though it’s on the tighter side, without being overly loose or boomy in any capacity. It finds a happy medium between tight control and a speed with some decay for some presence.

My only complaint with the T51’s bass is that it is simply too emphasized over the rest of the spectrum to my ears. A general reduction in emphasis would be preferrable. It would still be prominent and the main focus, but not as overbearing as it can be on the wrong tracks. The bass can overshadow everything else by sheer emphasis. Not necessarily bleeding into the mids, but simply being too focal a point which can be distracting. It can make lower range vocals come off a bit rumbly and warmer than real life which I found to be a regular occurrence while watching movies, TV shows, and general media.

That being said, the bass more often than not is more than satisfactory for my personal taste and needs, with a good balance between quantity and quality. Would have preferred just a tad less emphasis for more versatility.

The mids on the T51 are a mixed bag. The upper mids have a few peaks that take away from the T51’s otherwise enjoyable, though slightly withdrawn midrange relative to the bass.

4.5-5khz: Not as bad as the next peak, but it sticks out like a sore thumb, next to polite midrange right before, and right after.

6.5-7khz: More or less the upper mid to lower treble transition, and the strongest peak to my ears.

The midrange before the sudden rise at around 4khz is pretty smooth and enjoyable overall, if a bit recessed relative to the bass and upper mid/lower treble spikes. This makes things like vocals enjoyable if a bit polite in general up until you start hitting S/T/Z notes where it can become a bit tizzy and metallic. Thankfully, it’s not nearly as bad as some other headphones I’ve tested like Ultrasone’s Pro 900 and Pro 2900 headphones. The T51 will exhibit some artificial sizzle in the upper midrange, though it is more than bearable as long as the track being played doesn’t thrive in these ranges.

The T51 is not for those looking for an intimate, organic midrange, as it takes a backseat to the bass and upper mid emphasis. Despite these flaws, they ultimately do not take away from the T51 overall. There is much to love about the T51 than these inherent flaws can take away from. I may sound a bit harsh and negative, but I’m being objective here, and not making up excuses for the imperfections I find. After 7khz, there is a small dip again until 7.5khz where it spikes yet again until about 9.5, where the rest up top isn’t fatiguing by any means.

The T51’s treble energy will mostly be located below 10khz, which unfortunately is on the bad section of treble that can get quite fatiguing if your sources sticks to those ranges for too long. The upper range at 10khz and above is on the non-fatiguing yet sparkly side for enjoyable shimmer and air to instruments, though ultimately being on the smooth side overall.

This gives the T51 a warm tonality in general with decent shimmer and smoothness up top: Certainly one of the less offensive treble ranges that I’ve heard from a Beyerdynamic headphone.

The soundstage is about average for a closed headphone, though separation is quite good with a relatively good width. Portable, closed on ears don’t tend to excel in soundstage, and the T51 is about average in this regard. I don’t put that much of an importance in soundstage other than for gaming purposes, which isn’t something I would find myself doing with the T51.

Despite the noticeable warm tilt and upper mid/lower treble spikes, the T51 has a stable enough response, bringing vibrant clarity and detail. The T51 isn’t the best option for less than stellar recordings and badly mastered tracks, so I suggest feeding it high quality media at all times to get the most enjoyment out of it. This is somewhat of a conflict of interest, as a lot of my preferred music genres like Trip Hop and electronic genres tend to be badly mastered or of questionable quality. However, the good tracks sound absolutely sublime. Garbage in, garbage out. Feed it quality, and you’ll hear quality.

With the efficient tesla drivers, and maximum power input of only 100mw, the T51 is far from amp dependent, though it can at least benefit from tighter sounding amps that control some of that bass bloom, if anything.

The T51 caters to the high energy and impact crowd. It’s tuned to excite in the bass and upper mid range, so high quality, electronic rock, metal-type genres will suit the T51 quite well. Action movies are a blast, as well as games that live on immersion and ambience.


I’ll compare it to a headphone similar in tonal balance which happens to be my current, everyday headphone, the Ultrasone HFI-15G. They are actually similar in tonal balance and purpose. Both are quite prominent in bass, warm overall, with a touch of tizzyness in the upper range, though generally being smooth and inoffensive.

Starting with the bass, the 15G doesn’t reach as low and decays noticeably faster, being less invasive in general. The T51 blooms quite a bit in direct comparison, and can detract from the rest of the sound, whereas the 15G’s speedy decay never truly gets in the way despite it’s considerable emphasis over the mids and treble. Despite this, the T51’s bass is fuller and more engaging due to extending much deeper, with more harmonic decay.

Despite similar tonal balance, the 15G’s S-Logic places the certain section of mids even further out and distant, making it a bit more diffused sounding and incoherent compared to the more fleshed out general mids in the T51.

The upper mids of the T51 has more spikes and peaks, being more forward overall, where the 15G can sound quite recessed with lesser peaks. Neither are particularly effortless and organic up top, and both have peaks in the upper mids that can sound a bit artificial.

Due to the closed vs semi-open differences, the 15G’s soundstage is considerably more spacious and airy in comparison. It excels in this regard, leaving the T51 behind with it’s fairly average soundstage size and depth. For gaming/virtual surround use, the 15G blows the T51 away, with truly spacious and immersive sound.

Comfort-wise, the 15G puts the T51 to absolute shame. Night and day difference, really. First, the 15G is about half the weight of the T51, and is easily felt. Second, the flat, cushy, cloth pads on the 15G rest on the ears with considerably less pressure compared to the T51’s synthetic leather pads. If comfort is of top-priority, the 15G stands alone when stacked up next to practically every other headphone out there. If anything can be said about the 15G, it’s that it’s comfort is something other headphones should try and live up to.

Overall, the T51 is more fleshed out, coherent, fuller, and head thump inducing, and on a higher level over the 15G, though with more issues in the upper mid/lower treble range. In addition, the 15G can be worn all day without much if any issue, and as such, would be more likely to remain on my head for most purposes. Since my headphone use is heavily leaned towards gaming and movie use, and less for music use, the 15G would still be my preferred choice of the two, nine times out of ten, despite it’s less than stellar technicalities.

Final Impressions:

The T51 is definitely for those that like an energetic, lively sound that emphasizes the feel, pulse, vibe of the rhythm, and less about the direct engagement of accuracy in tonality of vocals or instruments. EDM or rock lovers would feel right at home with the T51, though be warned that the bass can be a bit overbearing if bass is considerably boosted in the mix. Badly mastered dubstep or hip hop can sound a bit fatiguing due to considerable bass bloom and tizz in the upper mids/lower treble.

The T51 isn’t the final word on detail retrieval and realism, and as such isn’t a prime candidate for acoustic, classical, or detail oriented genres. If you use the T51 correctly, it will reward you with a fun, dynamic, energetic sound. I certainly enjoyed my time with it, and I recommend it wholeheartedly for those needs.


  • Fun, energetic tonality
  • Deep bass extension with plenty of rumble and impact
  • Easy to drive
  • Build quality


  • Not for critical listening
  • Far from neutral or balanced
  • Bass is omnipresent, embedding itself where there shouldn’t be much
  • Peaky upper mid/lower treble sections
  • Relatively short cable and non-detachable cable, could’ve used another foot of length
  • Inline remote too close to the headphone

Overall, the T51 isn’t exactly what I look for in terms of design and features. That being said, I found myself enjoying it’s sound overall. I hope Beyerdynamic revisits this sound signature, while reducing the bass output just enough to keep it from being so omnipotent, as well as balancing out the upper mids (less peaks). They can keep everything else the same, and I’d be more than happy recommending it for even more purposes.

As it stands, the T51 is a very good, portable headphone that will undoubtedly be hit or miss depending on specific tastes.

Accessories Included:

– 1/4″ (6.3mm) gold-plated adapter: The standard variety adapter for use with home equipment/bigger devices

– Adapter cable mini-jack socket (3.5mm) – mini jack plug (3.5mm): I personally have no clue what this is used for as the cable already comes with a right angled 3.5mm plug.

– In-flight adapter

– Carrying case

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Christian Gabiel [Mad Lust Envy]

Under the name Mad Lust Envy, known for the surprisingly popular headphone gaming guide on Head-fi's Video Game Discussion sub-forum. Avid anime and gamer geek with a penchant for headphone audiophilia, though admittedly more for general media use, less so for music. Plenty of music listening when reviewing, however. While the headphone hobby started in 2010, it was full steam ahead from the start, never looking back.

  • sidspacewalker
  • 2016-05-27 04:55:00
  • Hi dude, really enjoyed your review. As an owner of a pair of these myself, I can relate and agree with all the points you've made. Lucky for me, EDM and rock are two of my favorite genres so I feel at home with these headphones haha. Could you please recommend me a DAC that would go along well with these headphones? I am looking into Dragonfly and Dacmagic XS.
  • Reply

  • Adrian Collazo
  • 2015-09-22 19:36:00
  • I was looking for a great pair of closed back portable headphones and read most of the reviews for the T51i. I decided to buy them (by the way, your review was the best). I've been listening to them for a couple days now. You are the only reviewer who mentioned the sometimes overwhelming bass issue - and for that very reason I've decided that I want to return them. I don't like the exaggerated low bass. Whenever I listen to any music with a strong funky bassline, it becomes so pronounced and thick that it is very distracting. This is not the case with every track I'm listening to - but it does happen with enough of them to bother me. I listen to alot of disco, funk, boogie and house. It's a shame because I know that most people wouldn't find fault with this - and really, these cans are excellent in every other manner. Would you say the Sennheiser Momentum 2 (either on-ear or over-ear would be a better choice for me? How's the bass on those? If not those, would you have a recommendation for an excellent portable closed back headphone?
  • Reply

  • Ian Cole
  • 2015-06-01 13:39:54
  • I've read many, many rave reviews for these Beyer headphones, and while I think of all those I've listened to, they are my outright favourite (the Momentums being nearest, but can't touch these overall, especially the weak midranges, a nd the even more emphasised bass and - to my mind - tizzy treble....but I still very much liked them!). However, whenever I read comments about the T51i cans being 'neutral' I was thinking 'absolutely not the case' every time I read it. No WAY are they neutral. They are, in fact, just as, you, Mad Lust Envy have described them, when being more critical. But as you say these are observations and don't detract from an otherwise truly excellent headphones. I don't regret buying them one little bit. I would buy them all over again. They are really superb, and as you rightly say, engaging! Exciting cans and very much more 'alive' than many other phones, IMO. They make music sound 'real' as opposed to a mere recording. They do 'add' in order to achieve this, but in such a great, open and balanced way (save the peaks you speak about). I think, in truth, this about as close a review to how these phones actually are, as I've had the pleasure to read. Thanks for just being honest, Mad Lust Envy.
  • Reply

  • Ismael
  • 2014-10-16 15:30:28
  • oops my bad lol
  • Reply

  • Mad Lust Envy
  • 2014-10-16 15:02:54
  • Yeah, it's a very exciting, portable headphone for sure. Thoroughly enjoyed my time with them while bangin out to Chillstep, Trip Hop, trance, etc.
  • Reply

  • Mad Lust Envy
  • 2014-10-16 15:01:37
  • Hi there Ismael. I'm actually the one to review these, not Frank, lol. :)
  • Reply

  • Michael Mercer
  • 2014-10-16 00:49:02
  • I've always loved Mad Lust Envy reviews - and you're DEAD ON again! I bought a pair of these cans for the reasons you speak of! I wanted a great, wearable, extremely portable set of cans for listening to my favorite underground electronic music - and they are perfect for that! I wouldn't use them to judge a mix, but, then again, I bought em to BUMP, while being a small-sized set of cans!
  • Reply

  • Ismael
  • 2014-10-15 20:06:22
  • Frank, with all due respect, feel bad for you, headphone enthusiast with sensitive ears, man that must be tough! Great objective review, I am looking to get a pair of closed portable headphones, now I definitely have to hear them first. Wonder how the compare to the HD-25s or Vmoda XS.
  • Reply

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