Superlux HD681 Semi-Open Over Ear Headphones Review

Written By Pete Anthony
Last Updated On: 3-23-19  

Superlux isn’t a company I’d heard of before looking into and eventually reviewing the HD681 headphones, and in fact their online presence was hard to find – they’re a ~40 year old company based out of Taiwan that, as far as I could tell, only has a localized domain, with pages that I needed to google translate to actually read anything about them.

But their headphones are apparently pretty well regarded by a lot of prominent publications and communities, and I’m always on the lookout for good inexpensive audio products that might be flying under the radar. Enter the HD681s, a so called semi-open back pair of over ear headphones.

out of the… yea there’s no box

The packaging was truly bare bones – the headphones were embedded in a single piece of cardboard and shrink wrapped, and the wire was twist tied in a smaller little box that was fastened to the cardboard. They shipped to me in a hard box, but there was no padding and nothing stopping these from banging around. I understand that packaging is typically the best place to cut corners with cheap audio gear, but it needs to be reasonably secure at a bare minimum, and these I’d say weren’t. A screwable 6.35mm adapter and basic carrying satchel come included and that’s it – no manual, warranty card, or any other such literature. The only information seems to be the company’s domain and a sales email address printed on back of the cardboard.

headphone front and back

One problem with the shipping is that the inner box was pressed against the fronts of both headphones hard enough to leave an ugly dent that you can clearly see in both the pads and even the inner foam. They’re still there after sitting unencumbered on my desk for a few hours and might be permanent, but, other than being unsightly, didn’t seem to impact the feeling or fit or anything.

The “semi” openness of the headphone backs is simply referring to the holes which, in addition to giving ear comfort via breathability, allow the sound to escape outward as well. Open back headphones have some argued sound advantages but are normally only seen in higher end products. Keep in mind that sound will audibly escape as you use open back headphones, so they’re not really meant for commuter use in public.

The headphones themselves are unabashedly huge, and easily fit fully over my ears despite being circular. The pad is nice and big too and feels comfortable, as does the faux leather. The headphones can slightly pivot omnidirectionally around a base cylinder.

The HD681 doesn’t have any on board controls and the wire is permanently fixed to the left headphone, pretty basic design there. The wire itself seems reasonably sturdy and is about six feet long.

the headband, adjustable sides and top

The headband is certainly the most aesthetically prominent aspect of this headphone – a fairly thin and very malleable faux leather band is fixed to two stiff wire things, but the result is that it’s one of the most flexible over ear headphones I’ve ever seen. They’re very malleable and don’t feel like they’re going to break at all when you twist and bend them.

The sides don’t actually adjust but rather have about an inch of give on each side, where the bottom knob thing slides up as the band is pushed out by your head. The idea I think is that these sort of “automatically” contour to your head. The clamping force is on the light side, kind of how I personally like it, but still reasonably firm.

All in all these look… not the best by reasonably standard assumptions, but functionally they fit quite well and are comfortable. The band does have a slight hotspot up top despite being so thin and malleable.

Spec/Performance Discussion, Listening Impressions, Other Related Observations

The sound was generally thin, and very flat, almost to a point that felt undesirable. The response curve kind of felt like a shallow U, as if the mids were almost escaping away out of the backs.

Overall reproduction seemed very even and consistent. But predictably there was some drop off at both ends. Superlux doesn’t have any readily available information on their product specs, but I imagine the response range is fairly average for this price tier.

The sibilance was fairly bad. Most songs felt thin and hissy, and certain songs more prone to that flaw became unlistenable in some cases.

The overall clarity was solid, and things generally felt tight.

The bass was surprisingly prominent and kind of thumpy, in a way that felt nice on some songs but bad on others.

The sound signature of these headphones definitely caused fatigue, and pretty quickly in some cases.

I had to crank up the volume quite a bit to get these to baseline listening volume. The combined 64 ohm impedance is on the high side for budget headphones, and while most devices should power these fine enough, you’ll probably have to crank the volume up.

There’s zero noise isolation and sound will, as I said, escape out the backs since they’re open, so these are definitely for use at home and not in public, and I don’t think I’d want anybody to catch me dead wearing these giant things anyhow.

The HD681 has a two year limited warranty which is good at this price range, where you’re normally lucky to merely get up to a year of coverage.

I listened to a lot of songs on these things – while they’d under perform in some cases they’d peculiarly sound great with other songs. I had a hard time pinning down any specific flaws that consistently generalize over everything. I suppose the takeaway I got was that these headphones seemed really unpredictable and inconsistent.

Random specific listening notes:

  • Daft Punk; Give Life Back To Music – pretty solid overall, response feels very even, percussion sibilance is the only noticeable issue
  • Daft Punk; Get Lucky – bass is a little muddy and distracting, percussion sibilance is noticeably less and better, Pharrell’s voice has a very weird sound like someone is hissing the lyrics along with him
  • Daft Punk; Lose Yourself to Dance – bass is not good, a lot of resonance, recessed, no pitch/tone, Pharrell sounds a little better here, can’t hear weird hissy ghost sound anymore
  • An Endless Sporadic; Impulse II – sounds really good, no perceptible complaints, great clarity, can really hear fast symbol rolls, percussions in general sound very true to the source
  • Trinity College Choir; Ubi Caritas – didn’t sound great, choral vocals generally very flat, no warmth. Significant imbalance, can’t hear tenor parts well, baritone/bass parts completely disappeared sometimes.
  • Clean Bandit; Rather Be – beat sibilance, midrange significantly recessed, song feels like an upside down U
  • Steely Dan; Peg – drums feel overemhasized and forward, Donald Fagen sounds more quiet and removed than usual. Chorus had unexpectedly nice pop and didn’t fall flat though, which surprised me
  • Steely Dan; Josie – guitar and bass noticeably off balance, bass recessed, Donald Fagen sounds removed again, airy and thin, choral hook definitely fell short this time
  • Bag Raiders; Shooting Stars – synth organ build up had a hiss with it that was awful, drop was a harsh yet recessed cluttery mess, song was unlistenable
  • Deadmau5; The Veldt – thin, flat, sibilance. Song that normally is round and mellow for an EDM became harsh.
  • Lil Wayne; A Milli – bass drop felt strong and solid, but it quickly fatigued, song otherwise sounded fine
  • The Chainsmokers; Wake Up Alone – female vocals totally overpowered ambient background midrage, which I basically couldn’t hear. Drop sounded pretty nice, but there’s general midrange recession
  • Earth, Wind & Fire; Sing a Song – brass and strings were very recessed, song just sounded weird and off
  • Jamed Taylor; Shed a Little light (live) – intro a capella was just bad, thin, background vocals disappeared, borderline unlistenable
  • Ludovico Einaudi; I giorni – orchestral instruments were just flat and recessed, general lack of detail
  • Nas; The World Is Yours – entire musical component of this beat feels just disappeared, Nas sounded good though, good clarity on the percussive beat.
  • No Doubt; Hey You – Sounds pretty good, punchy guitar is there, Gwen’s Vocals are a little recessed, particularly when she gets higher, imaging was just completely off on harpsichord solo, could only hear it in my right ear, caused immediate fatigue
  • Rage Against The Machine; (various) – sounded very solid all in all, no perceptible complaints
  • Sister Sledge; Thinking Of You – great clarity, could really hear the bass line and violin harmonies, all in all an unexpectedly pleasant surprise at this point
  • Vanilla Sky; Umbrella – sibilant cluttered mess, super thin, sounded pretty terrible, unlistenable
  • Bob Marley; She’s Gone – it sounded good, except the bass was unbearably muddy, fatigue and resonance, no tone/pitch
  • Fleetwood Mac; Seven Wonders – significant midrange recession, couldn’t hear the normally awesome background instruments in this song
  • Pantera; Cowboys From Hell – sibilance really bad, vocals recessed, didn’t sound great
  • I’m Coming Out; Diana Ross – sounded solid over all, no perceptible complaints, vocals sound really nice here
  • Queen; Gold Old-Fashioned Lover Boy – sounded decent, but Freddy Mercury’s vocal/harmony style doesn’t syngergize well at all with the general style of these headphones

Overall Take, As Compared To The Competition

The Superlux HD681 has reasonably even and consistent reproduction, but a very thin and flat overall sound with perpetual sibilance, the latter of which seemed to cause really variable and unpredictable quality across specific songs. They’re pretty comfortable to wear at least. This niche has become very competitive though, and there are as or even less expensive headphones that generally sound better and are more consistent. And, for not that much more money, additional options open up that sound significantly better.

See the Superlux HD681 on Amazon (affiliate link)