Superlux HD-668 B

If you want to know how good these headphones are, consider that I have never written a review about any product I've ever owned. These should be at the top of the list for anyone searching on this site for a good pair of entry level headphones. Lots recommend the Porta Pro's and I am not one to say otherwise, but the design of the unit is somewhere around 30 years old and they haven't updated the materials. So I decided to go with these after looking on youtube and this forums for weeks. I've made a great choice and they sound great. Do not, for any reason, listen to anyone comparing these to $600 headphones. They shouldn't be compared. For $50 you will be blown away. For anyone looking for a $50 set of "cans" then you won't be disappointed by build quality or sound. They are great.
 
Pros.
Amazing sound for $50
They fit my big ass head.
Detachable cord
Two cord sizes that can connect and form one long cord.
1/4 inch adapter for your receiver
 
Cons
Make your ears sweat
Highs can be a bit much.
Puts a decent amount of pressure on the head
Do not isolate at all. These are private listening time headphones. Ambient noise will come right thru.
Open design so they naturally leak as bad as the isolation.
 
*************************Update
I've owned these for about 2 months now and wanted to do an update. I'd like to just warn dubstep and rap fans. These will not suite them. I'm a huge rap fan and listen to it often. The bass can't extend low enough to really sing with those genres. Don't get me wrong, they clear the fence but just by an inch. The highs have really relaxed after burn in. They are no longer piercing and fatiguing and have mellowed down. They can still use some adjustment based on the genre but they are livable now. Comfort is an issue now. They clamp pretty tightly and with the pleather pads being so stiff, it can get annoying. I'm thinking of getting the velor pads for these or try to change the padding. Seams like a lot of complaints on a pair of headphones I so recently gave much praise, but don't forget that these cost $40-$50. All forgivable when you remember the price. These headphones shine with house, jazz, pop, acoustic, most rnb or neo soul. They have great mids and listening to bass or bass guitar is a treat. For this price, I still highly recommend these headphones. They are not portable but if you don't have kids or a noisy house. These are great. 

Let me start by saying I don't normally write reviews on the official level, star system with graphs and all. I do look at them religiously when trying to find info on a HP, DAC, or AMP that's sparked my interest. So here I am reviewing on the Taiwanese made Superlux 668B which is quite obvious a mix of AudioTechnica's wing headband system, AKG K studio series body, with Superlux's driver. Aside from the last bit, obviously all are homages or clone of their respective brands. Not the first time one brand took from another however.

With that out of that way, let me start by saying at less the $50 shipped, not much can go wrong. The headphones look and might feel somewhat cheap on the cups but before you judge, plug the sucker in and have at it.

Notes:

- Quite obviously the headband's wing system is something you'd find from AudioTechnica's line. Similar to AD900X and the likes. The headphone feels quite secure but the the two wings takes time getting used to. I'm hoping with time they get somewhat softer and less obvious. Aside from the two wings pads, the headphone is very light and does not feel like you're wearing a headphone at all. Clamp force is very good in gripping your head but not overly where it hurts (like a DT880 Pro when new). I've tried pointing my head downwards to try and get the HP to fall off, doesn't even budge. For reference I wear a 7 5/8" fitted hat, I fare on the big noggin side.

- The cups are made of plastic, they feel and look cheap. Aside from the opening of the grill, the cups look exact clones of the AKG K studio series (K240 for example). From the way the cups swivel up and down on the driver housing, the way the headband goes into the housing, as well as cable entry and run from one driver to another.

- The earpads are pleather and aren't too bad, although I can see some Hifiman velours or similar would do great on comfort. As is, it's not too bad. They're soft but not memory foam or anything fancy. The feel isn't too bad either, I've seen worse.
 
Now the most important part, SOUND.

They've been running for about two hours now and there's already a noticeable difference in treble. At first it sounded rough and spikey but after 60 mins it's calmed down quite a bit. From word around here, 50 hours would produce the final sound after burn-in. First these are what you would call reference type headphones, neutral sounding and fairs to the bright/airy side. No dark stuff here and if you seek a bass-head or a warm phone, look elsewhere. What I can say however is the clarity on these phones are fantastic. Dry sounding, it pairs well with tube amps for a more musical flavor but does well with solid state if speed and attack is of priority. With an emphasis in the treble end, they air on the bright side  The treble does get too hot with poorly mastered tracks, definitely a bright and airy phone that does well when the music fed is greatly recorded (loud war tracks need not apply). The bass has a steep roll off after 60hz, sub-bass rumble is non-existent but bass is pronounced from 60hz and up. Nothing sloppy, but unamped the drivers can lose control when the sound swells. Soundstage isn't very wide, I would say comparable to the DT880's semi-open width. Instrument separation are great, you can easily follow different instruments in a piece without it getting lost when you've got 3-4 different going at the same time.

These sound to be about 85% straight from a cell phone, a plus if that's all the source you have or need to use it on the go. When amped, the HP can keep things tight and true. It doesn't take a whole lot to get these going as well, plugged straight to my Lenovo laptop I'm having to use 50% of the volume bar to keep things at a sane level. These are 56ohms with the rating of 98db/1mW according to the box.

I've never heard anything in the full size realm that sound like these at this price range. It definitely holds up to the hype and praises it gets as reference or studio quality. If you prefer a bright tilted phone with a dry and clear sound at less than $100 this is something that should be in your shopping list. At the normal price of around $40, these are a steal of a headphone. It's great as a value minded HP, backup, or something to let the kids chuck around. I'm one for great value and willing to spend the money if it warrants it so when something with great value comes around it definitely sparks my interest. If you're looking for something that won't leave a hole in your wallet that will compare very to mid-fi headphones, this is it. A definite listener's headphone, not very show worthy but when your friends ask what you spent on it, you'll look like you've done some homework with your purchase.

As the saying in the title goes, this has never been truer than for these headphones.
Thankfully, Superlux sells sound quality, not an overhyped brand name. Can you really get great sound for $40? Oh yes, and it's right here.
 
I was recommended these headphones by a fellow forum member and after a day or two of investigation I decided I really liked what I read about them and figured if it was true, then these would be the best headphones I could buy on my really limited budget. So, I did.
 
Before I give any impressions, a small disclaimer: My previous headphones were Trust HS-6200 5.1 USB, and Trust Multi Function Headset 310. The most "hi-fi" component I have in my house is a set of Logitech Z-5500's. They run via coaxial, while everything else runs from the motherboard Realtek ALC889 codec (best Realtek codec, but still onboard.) So, I have not had much experience with quality components, but I know how to trust my ears. Hopefully, this will be enough to make a relatively accurate assessment of these headphones. Let's take it from the outside in.
 
Design: Well, the first thing that surprised me is that they are relatively small. I expected them to be a bit larger from the pictures. The next thing is, they are really light, weighing only at around 200 grams, which is good as it makes them easier to keep on the head for longer periods of time. The build is fairly sturdy and the plastic is of good quality, they look like they will last long. I'm not going to comment much about aesthetics, aside from the "Studio Monitor" labels being a bit tacky, but I generally like the way they look.
 
Comfort: A bit on the tight side. Causes my ears some discomfort after having them on for a while (upwards of 2 hours), but after a few minutes break it's good. I've read some people claim it made their ears sweat and heat up, I haven't had those problems but I don't normally sweat much anyway.
 
Accessories: With these headphones you get a 3m cable (for PC use) and a 1m cable (portable use) which you can exchange and even combine together. You also get a 3.5 (1/8") to 6.3 (1/4") mm jack adaptor, which is a nice feature, and a carrying pouch to, well, carry them around.
I liked the cable flexibility the most, I think it's a great idea.
 
Sound: And here we go, the most important part. I'll try to refrain from analyzing these headphones in the typical fashion here such as how the "highs, lows, mids, etc." sound as I don't think I'm familiar enough with the terms here but I will attempt to describe their overall sound signature with my limited experience, so here goes. What you play through them is what comes out. A bad recording will sound bad, a good one great. They are really transparent, simply "passing on" the sound without leaving a hint of presence of their own. And honestly, I like this. I want to hear my music the way it was recorded, intended to be heard. I don't want headphones to change my music. Sure, colored headphones may make it sound more "fun", but that's not the way the artist heard or made the track. Well, to each his own I guess. To continue: they reveal a lot of detail. A lot. Background hiss, noise, breathing, coughs from artists and stuff I have never heard before in my music. I have to play through everything again, to rediscover all those tiny details I missed out until now. The frequency response doesn't have many spikes, and it corresponds with what you can see on the manufacturer's website.
Soundstage, well, it's generally good. Certainly better than the closed-back headphones I own. These are only semi-open however. Sound isolation is still OK, I can hear myself typing and my noisy PC case, but when music plays it's hardly audible. To sum it up for the Superlux HD668B: Add nothing, reveal everything.
 
Oh, one more thing: the bass. I've seen a lot of people claim the bass isn't strong enough, while a few claimed the bass was good. And I believe I know why. It actually depends where you plug them in. If I plug them into my PC case's front port, the headphone out on the Z-5500, my cell phone or MP3 player, the bass is overwhelming, in fact there is more bass than there is in the 5.1 headphones that had a dedicated subwoofer inside, and it certainly does not sound natural. However, if I plug them into the rear ports on my motherboard where there is supposedly a headphone amp the bass tames down by around 80%.
 
EDIT: After a bit of longer listening, I've realised that it's not the amount of bass that changes. It's the amount of mids and highs. The thing is, the output ports on the back of the motherboard are assignable. If I set the jack to "speaker out" they give a line level signal, and the headphones sound substantially less clear and you have to turn the volume up from 35 to around 80; this gives the impression that the bass is louder - it's not, it's only that the signal is not strong enough to drive the mids and highs up to point. When switched to "headphone" setting, the headphone amplifier kicks in and the higher frequencies -really- jump up, leaving the bass behind at the "normal" level. This is why it seems it has less bass. So even though these headphones are only 56 Ohms, they certainly benefit from amping, and well at that. Line-level won't cut it.
 
Overall, I am extremely happy with them, will keep them around for a long time. My next purchase is going to be an Asus Xonar Essence ST, I can't wait to hear what they will do then. Well worth the money I paid for them and more, and would recommend them to anyone in this price range, for sure.

Lot's of Audiophiles own these they but can sometimes be like a wild horse that needs taming gotta eq and lightly amp to get best out of them - five times as good as
Audio Technica ATH-ES-700's for example IMHO not as great as the UE 600's. Fiio E17 sounded really good with these. A Valve Amp like the Bravo even better 

Killer headphones for the money.  Very hard to dislike. People who probably paid more money for AKG K240's (which sound inferior) would probably criticize them. I work in the audio retail industry and have experience with Grado - full line, Sennheiser - full line, AKG full line, Goldring, Beyerdynamic. 
There is definitely something magical about their sound that makes me return to them again and again even though my collection includes: Sennheiser - HD600 and 250II Linear, Beyerdynamic DT990pro, 770 - 600 ohm, AKG K240 - 55 ohm, Grado SR80 and I-Grado.
I have to mention  that I did few mods: First I removed the thin black fabric from the enclosures and replaced with organic cotton pads one for each side.  Second I replaced the logo plastic caps with wooden ones and third I cut felt pieces and replaced the bass pads that cover partially the drivers (mine cover tiny bit less)
I listen mostly classical music, jazz. I also listen some 70's prog rock, acoustic rock and electronica. I listen analog or uncompressed digital files (SACD, 24/96, 24/88.2, 16/44.1)
I don't know how MP3 will sound with the HD668B .  I use FLAC on my portable player and the sound is pretty good. People who are complaining about comfort should listen Grado SR60 for couple of days and switch back to the HD668B.
I think the HD668B are killers for their price and Superlux is a great company which makes affordable products with great sound quality.  Now enthusiasts and professionals who couldn't afford to buy 5 pairs of AKG's for their studio can do that with Superlux without compromising the sound.

I have many audiophile headphones like sony zx700,koss porta pro,soundmagic e10,pl 11,skullcandy uprock,. out of whole least nothing sound better than my superlux HD 668B. this headphone is must for audiophiles who want their instruments to hear every note with ease. guitar sound will blow ur mind. may be not comfortable as zx700 but sound is awesome. bass is adequate. goes deep and low but rumbling is not present as soundmagic E10. u can hear every sound with ease. bass does not disturb the whole frequency response. sound is neutral,no fake sound,lower mids slightly recessed. it has detaching cable of 1m and 3m respectively. u can remove the pads and change with akg 701. though u will not feel pain for 2 or three hours(sufficient for movies). these are open back headphones and sound leaks through it which is not a problem for me. sound is spacious with excellent instrument separation. if you want a sound for $150 in $50 then these are for u. may be they are not built strong but if u look on the heart of headphone which is its sound, these are above par and are better than grados.


if u want a true audiophile headphone then look no further.

Hi,
I did test the HD-668B on my modified SMSL SD793II dac & headphone amp
where the sound is great and a bit more focused than the HD-681 (but both headphones are close)
After listening the HD-668B, the HD330 has too much bass with overall heavier sound       
 
There is a lot of details, the voices shine.
The bass are deep & clear.
The trebles are very clear, when they are hard,
they only reflect the poor quality of the amp or dac
If you improve the quality of electronics, you will hear it through the HD-668 B
 
I am very impressed with the soud you get directly on a Samsung Galaxy S3 (Wolfson WM1811 DAC)
it is a pefect match, better than the 681 (too much spatial)
Jerome

Brilliant performers. Very detailed, I can spot imperfections instantly now. Great value for money. Definitely the best headphones under €100. Never even look at my hd 598's anymore.

First that all. Im gonna say to all who wanna buy these that these headphones need Burn In, You will notice too much highs the first time. And yes, that was my first impresion of these, Too much highs and sibilances, but after a week I started to notice a improve in the highs and they started to sound awesome.
 
So lets start with the Sound:
 
Bass: Punchy/Fast Midbass, Sub-bass is weak, but overall they give enough bass energy.

Mids: Nothing special here. They´re OK. (Even after this edit I cant still say something bad/good about their mids, they are OK.)
 
Highs: They are bright, These highs are amazing, they give them more energy, trumpets, Saxos, Cymbals sounds amazing. I dont understand why some people say that these are too harsh or they have too much sibilances, yeah they have sibilances but I dont feel them excessive or annoying.
 
Also, their timbre isnt the best, somewhat dry,
 
Gaming: Very detailed and relly good soundstage, I remember my first COD 4 match with these, I even heard enemies across the COD 4 Map Showdown. That was awesome and since that day. I cannot play without them. (Edit: This is no longer the case xD).
 
Edit: I recently posted my review of the Superlux 681 Evo where I compare them a lot against these headphones: http://www.head-fi.org/products/superlux-hd-681-evo-black-professional-monitor-headphones/reviews/14340

Sound Quality:
 
amazing soundstage
analytical
recessed lower mids (little)
dynamic
Neutral
 
 
comfort:
 
the ear pad are horrible they make my ear sweat after wearing them 5min+. they are tight at first but get better over time.
 
 
 
 
 

I apologize if I duplicate the findings of others. I read the other reviews, and I'm trying to address the things I thought haven't been talked about yet.
 
 
The current (it changes, it has too I guess) price (HD7 version) is 29.00 USD w/free shipping.  (Musician's Friend, and a few other "musician" websites.  NO CONNECTION.)
 
I had to wait quite a while to get them.  The Presonus HD7 option would've been faster, cheaper and less hazardous to the merchandise.  At least potentially.....
 
I used the center "pads" from the Velour aftermarket cups in addition to the Super Lux's own pads, and that made a perceptible difference in taming an EXTREMELY DETAILED (and clean) top octave (above 10,000 or so)  My experience was that I couldn't wear them for extended periods of time until I let them run for several days.  The bass is well controlled, and it has improved in dynamics (slam, if you will) over time.  It's no Ultrasone Pro 900 (It's not even a Senn 600 or 650 either at either frequency extreme) however the mids are quite full and (this word's a little annoying to objectivists, but it's not totally out of place) lush.
 
 
The trip from Taiwan was apparently fraught with hazards.  I'm going to contact the seller (Amazon) and look into what happened to the box (it took a HARD lick to its upper left hand side, the phones and accessories were fine though).  I feel certain they'll have no explanation.  I wouldn't if I'd sent something to Taiwan from here.  The 668B is a bargain at twice the price, but don't pay that much if you don't have to.
 
The driver reminds me (more than anything) of the driver from my first "high fidelity" headphones from the early '80's (I'd owned junk headphones before that) the Koss HV/XLC.  There was also a RS version of the same headphone, but without volume sliders on each cup.  (I owned both, until I bought my Senn HD-600's in the late '90's.)  The highs are more extended on the 668B, the Bass is about the same, but doesn't overdrive as easily as the Koss phones did.  (You could make the diaphragms of the HV/XLC "kack" with too much bass in the program material).
 
It's my first choice for "away from the house" needs, because if it gets trashed, it's not a $300.00 catastrophe.   That alone makes a strong case for its inclusion in your collection! 

Amazing Headphones.
 
I 1st found out about these cans when I walked in on a new audio shop in our local mall. They had a lot of cans and IEMS available for audition so I listened to one. I was blown away with the detail and just about everything, there are also some Sennheisers there but these really stand out for me I couldn't put them down. My first thought was these must have costs more than those Senns but when I asked the salesman he told me it only costs around 40$. Wow! Really? So I researched about the brand and found out it was really praised very well here and other audio sites. Long story short, I bought 1 the next day.

I won´t repeat what everyone else wrote before - because it´s true. I´ve listened to a Beyerdynamic DT990 once and while I love my Sennheiser HD-600 a different cup of tea would be nice sometimes. But then, Beyerdynamic headphones are a bit too expensive for the sole reason of being able to listen to "another flavour". Thank God there is Superlux. You´ll get so much material for your money. You´ll also get very good, Beyerdynamic-like sound. You can even improve the sound if you replace the pleather earpads with the velour pads for the AKG K-240. I don´t know why but they sound a bit more balanced and refined with these earpads. Further improvement can be achieved by putting paper tissue between earpad and cup (increases the distance from ear to driver and will likewise improve comfort).
 
If you do these two things you´ll get a headphone that will rival headphones for 150-200 Euros: they are dynamic, precise, crisp, balanced with a very good soundstage. They are easy to drive but they will sound best with good amplifiers. They won´t be impressed by loud or harsh music, they will just play along with just the right amount of directness. Some people would argue that this makes them sound a bit "bored" - which sounds almost insulting to me because they are anything but boring. People seem to confuse balanced sound with boredom. Well, let me put it this way: if you want your headphone to colour the music you´re listening to... go and search elsewhere. The Superlux does indeed add a bit colour (around 7.000 Hz) but it´s not very much and it´s not distracting. However, lower mids seem to be a bit underrepresented - but I could be fooled about that because I´m accustomed to the comparatively (to the Superlux) warm mids of my HD-600.
 
All in all, very, very good for the money. A true bargain, thank you Superlux.
 
P.S.: before I forget... they need considerable burn-in time to sound their best.

I’m way late to this party but you know what? I’m glad I came. Have you been looking for a super affordable headphone but are overwhelmed by all the choices out there? Let me simplify it for you; The Superlux HD668B is exactly what you’ve been looking for.

Superlux was started in an apartment building in Taiwan over 30 years ago. They have continued to grow and now have a huge facility in the industrial zone at Lan-Yuan port, China, where they make headphones, speakers, microphones and a bunch of other electronic gear.

At the time of writing, the Superlux HD668B is listed at $34.99 and is available at Gearbest here.

This product was provided for the purpose of an honest review. I’m not affiliated with the company and all observations and opinions here are my own.

Pros

• Punchy, articulate bass
• Clear and detailed sound
• 2 cable extensions included
• Price!

Cons

• Stock earpads are a bit thin

SPECIFICATIONS

• Drive Type: Semi Open Back
• Frequency Response: 10-30kHrz
• Sensitivity: 98 dB SPL/1mW
• Maximum Power Input 300mW
• Impedance: 56 Ohm
• Weight 7.8oz (222 grams)
• Cable: Removable 1M & 3M
• Plug Adapter: 3.5mm to 6.5mm (1/4 inch)

Package and Accessories
The Superlux HD668B comes in a large but simple box with an image of the headphones and model number on the front. On the back and sides are some features and details of the included accessories.

When you open the box you see the provided cloth carrying/storage bag. The headphones are secured in a cardboard cutout which holds them in place. It’s a simple presentation but it’s practical and the basic materials used help to keep the cost down.

Included in the box are:

• 1x Superlux HD668B headphones
• 3.5mm to 6.35mm adapter
• 1x 3 metre female to male 3.5mm cable
• 1x 1 metre female to male 3.5mm cable
• Carry bag
• Cable clip
• Instruction manual

That’s not too shabby considering the price you’re paying. Having the two cables provided is really something I wasn’t expecting but it’s very appreciated and also a very practical addition. At this point, just seeing my first glimpse of the headphones and the two cables, I was already thinking what great value this is.



Build Quality and Design
To be honest, I wasn’t expecting much in terms of build quality. I mean, heck, I consider $35 cheap for earphones but for a full-sized over-ear headphone? C’mon! As I lifted the headphones out of the box my anticipation grew.

Why, you ask? The answer is simple; Because they feel pretty good! They’re very light but not at all loose or flimsy. Everything feels pretty robust a solid.

At the heart of the build are the spring steel wires that form the headband. They run from the top of the headphones all the way down to where the earcups are attached. Partway down the wires is a plastic joint on each side which adds some rigidity and also holds an additional pair of wires that are attached to the self-adjusting “wings” that sit on the top of your head.

The earcups are large and made from a light but robust plastic. There is a series of concentric circular holes, covered with a metal grill, place around the centre of the earcups. These give the headphones their semi-open back characteristic.

The inner part of the earcups pivots slightly in and out, while the spring steel wires twist back and forth, so the headphones naturally find the right position on your ears.

Looking at the earpads, they’re quite large and easily fit right around my big ears. The pads are made from a PU leather with a foam interior. There’s also a sheet of foam covering the drivers so there’s some padding between your ears and the driver covers.

These pads are easily removable, so you can replace them if they get worn or you can get some third-party alternatives for added comfort.



Comfort and Noise Isolation
I find the Superlux HD668B extremely comfortable to wear. The clamping force is sufficient to hold the headphones securely on your head and you can move about easily without fear of them falling off.

Thanks to the large diameter of the earpads, any pressure is spread over a large surface area so they don’t cause any discomfort at all. The only thing that might be an issue is the earpads becoming quite warm, due to the firm pleather covers. I imagine if I were to upgrade to some third-party replacement pads, the HD668B would be every bit as comfortable as my Beyerdynamic DT990 Pro.

Being a semi-open back, the HD668B does not have much passive noise isolation. I can still easily hear the clacking of my mechanical keyboard as I type this, as well as the television in the background. This is normal for this type of headphone and if you’ve had open or semi-open back headphones in the past you’ll know exactly what to expect.



Cables
Finally, there is the external cable connector that differs from the usual female jack type on most headphones. The HD668B has an external 3.5mm plug, onto which you connect a female 3.5mm cable extension.

Both the 1-metre and 3-metre extensions terminate in a straight 3.5mm plug which is perfect for connecting to a mobile phone, portable DAP or computer. There’s also the included 6.35mm adapter if required to plug into a desktop amplifier.

As for the cables, they have a smooth, black rubberized sheath. They’re fairly supple and don’t have any kinks or unruly bounciness. Another bonus with the cables is that there is almost no microphonics at all, even when walking around. In fact, holding the cables in your hand you might wonder again – how can they provide all this for so little cost?



Sound
Any scepticism I had vanished as soon as I heard the first notes coming from the HD668’s transducers. These things sound ridiculously good (in the context of their price). I was greeted with a mildly V-shaped signature with a touch of warmth, along with clarity and detail.

The tonality is superb, the balance is just right – not analytically boring, nor overly fun coloured. There’s a healthy dose of bass impact, clear and intelligible midrange (albeit a touch recessed) and airy, crisp treble.

GEAR USED FOR TESTING

• ATC HDA-DP20
• Acoustic Research AR-M20
• PC/MusicBee > Topping DX7
• Samsung Galaxy Note 5

BASS
This is one of the most surprising aspects of the HD668B. The bass is well articulated, textured and doesn’t show any sign of bloat or woolliness. Mid-bass has nice impact with a fairly fast but natural decay. There’s no noticeable bleed into the midrange. I love the quantity of the bass in relation to the mids and highs. Clearly, the person who added the B (for balanced) to the model number knew what he was talking about.

Sub-bass also has a satisfying goodness. There’s a nice weight to it and a fast, controlled rumble which, similar to the mid-bass, does not intrude over the midrange. The HD668B revels in its control here, bringing the party without the associated hangover.

MIDS
The midrange has great tonality throughout. Lower mids are a hint lean but still have enough body so as not to sound hollow or too distant. The upper midrange is a little more upfront and can be a little edgy on occasion but having said that, it’s an area my ears are particularly sensitive to.

Vocals sound natural and come through with clear intelligibility. The HD668B renders voices with just enough warmth that they sound organic but maintain clarity and texture.

TREBLE
The treble is light and airy with a hint of sparkle. Detail retrieval is very good and for the most part, the treble is non-fatiguing. On brighter tracks, some sharpness can be detected but that’s mainly due to the HD668B’s transparency; it doesn’t try to smooth over the treble but rather aims to faithfully reproduce the recording.

SOUNDSTAGE
The Superlux HD668B presents a soundstage with above average width and plenty of height, accentuated by its airy characteristic. While the depth is fairly ordinary, instrument separation is still good and maintains some space between various elements.

Comparisons
BEYERDYNAMIC DT990 PRO – 250 OHMS ($160)
The DT990 Pro is more heavily V-shaped, with more accentuation in the treble. The Superlux HD668B has just a little more weight in the mid and sub-bass areas. Both share a similar width in the soundstage but the DT990 Pro has more depth and roundness to its stage.

Vocals are a touch more recessed on the DT990 Pro, however, it does have a slight edge in tonal accuracy. The DT990’s vocals are a little richer and vibrant, where the HD668B is somewhat dry. It’s really amazing how similar these headphones sound, the biggest differentiator is the treble. On the DT990 Pro, the treble has more sparkle but it’s also more strident and fatiguing.

In terms of comfort, the DT990 Pro is superior. It has slightly less clamping force and of course, has those lovely velour earpads that are thicker and softer. I’m fairly certain though, that if I were to put the Beyerdynamic pads on the Superlux, the comfort level would be near identical.

MSUR N650 ($90 – $100)
A bit of a hidden gem, the MSUR N650 has a warm and inviting sound. It’s got more mid and sub-bass than the HD668B but doesn’t have the same masterful control. Bass on the N650 carries more weight and has greater impact, giving the overall signature warmer overtones.

The N650’s midrange has denser notes, making vocals more intimate and closer to the listener, even though the N650’s midrange is more recessed.

The N650 shares a similar treble to the HD668B, which is crisp and airy. Its soundstage is not as wide but it does have more depth and superior imaging.

Comfort-wise, the N650 has softer earpads but they sit more on the ears rather than around the ears like on the HD668B. Both headphones are initially comfortable but I find my ears need a rest with either one after 1 – 2 hours.



Superlux HD668B Conclusion
The Superlux HD668B is simply brilliant for such a low-priced headphone. Even today, it still holds its own against products costing double or triple the price. The balanced, airy and transparent sound will surely surprise you and likely exceed your expectations.

In light of all this, I’m stumped as to why there are so many 4 star reviews for this headphone. Sure, that might be accurate if you were looking at it purely based on sound quality alone. But when the cost is taken into consideration it’s a no-brainer. Add to that the comfort, build quality and the fact that you get 2 cables as well, the HD668B is easily worth full points, IMO.

So, if you’ve been looking for a really inexpensive headphone to start your audiophile journey, look no further. Get yourself some of these today.

*This review was originally posted on my blog. You can see my other reviews over at Prime Audio.

I have written a review in danish at the danish head-fi-forum, which is called Hoved-fi.dk, and I'll now do my best to translate it into english:

I have on a few occasions heard of Superlux, and that their headphones, despite being low cost, aren't the worst one can buy.

A few days ago, I had the opportunity to buy a pair of HD 668 B's for what equates to roughly 21.50$, including the cost of shipping and a pair of velour earpads.

Naturally, before recieving the headphones, I had seen quite a few written and video reviews of the HD 668 B, but since I do not seem to share sound preferences with a whole lot of reviewers, I am never quite sure what to expect from a headphone.

Finally: The arrival of the HD 668 B's! I removed the stock "leather" pads without even trying them with the headphones, as all of the reviewers mentioned that the stock pads were awful. The velour pads are very comfortable, and because the headphones weigh next to nothing, they are also comfortable for longer listening sessions.

The build quality regarding the rest of the headphone can best be described with the words: "You usually get what you pay for"

Except for the headband and the holders for the "wings" that rest on your head, the headphones are made of plastic. They dont squeak or rattle when handled, but apart from that, there aren't many more nice things to say about the build quality.

Not that they are going to fall apart with everyday use, but on the "nice-materials-scale", I'd give them a 2 out of 10 - because there at least is some metal included in the construction.

The headphones are sold with (I believe) a 10 foot and a 3 foot cable. I got mine secondhand, and only got the longer of the two cables.

The cable is rather thin, but is at least detachable, so if you happen to step over the cable, it should just come right off - if not, the cable can be replaced as described.

The 668 B's make use of what I'd describe as "wings", that rest off the top of your head, and prevents the headphones from sliding down. The concept is fine, but you might have to bend the wings (carefully!) a bit, in order to adjust the clamping pressure on your head.

The sound:

I have owned a pair of Hifiman He-350, that I'd - before owning the 668 B's - describe as being bright. HD668 B is, however, even brighter, and a bit more aggressive.

If you'd like a bit more lowend, you can try adding more layers of foam in front of the drivers.

If you one day find yourself with 30$ you don't know what to do with, I'd recommend you try out the 668 B's - If my description of the sound seems like something you'd like.

I am not going to go more in-depth about the sound, as I do not consider myself to be experienced enough to properly describe other sound characteristics - and I do not want people to be mislead by improper descriptions

This headphone could give you an excellent sound stage without high- piercing treble and thin bass with one condition - you need a dedicated amp for this one to shine.

Although this headphone stated about 56 ohms for each side, 112 in total and should be easy to drive with just any setting, it is not. I have tested with Asus Xonar Essence STX. At first, I used a low-gain in headphone amp setting and experiences all negatives everyone found in this headphone. However, after switching to a high gain amp setting, everything was changed for the much better.

This one is by far the best value headphones for its price if you have a dedicated headphone amp for it.

It has been a LongLong time since i bought a remarkable product at such a low price. Full Stars for Value!
 
Soundquality wise, this headphone has great detail and clarity and WIDE soundstage. Instrumental separation is very good. Makes it a very good headphone for gaming(which i did.) It just sounds so nice that it can even compete with headphones in the $100-200+ price region. A REMARKABLE PRODUCT BY SUPERLUX. 

These headphones don't seem to add anything to the recording. It feels like they have absolutely no color of their own. Good recordings sound incredible good! Mids are delicious but not overly emphasized like in some phones. Bass is not weak, very strong actually, and it goes deep, but it's volume isn't too loud. I use a little EQ to give bass a boost. Highs are best I have ever heard. They are delicate, soft, not too bright but still very accurate. And they extend really well. 
I am just listening to music with these, not headphones. These are very detailed headphones, so every nuance in original recording and source comes through. The soundstage is very realistic.  
 
Build quality felt a little cheap at first but the excellent sound quality makes up for that. Headphones are very lightweight so they should be comfortable. The auto adjusting design means that the wing pads press a little to my head. I need to keep breaks after two hours of listening. 
 
These are very cheap headphones but that is only a huge plus. If you want to have quality sound and also pretty comfortable phones then pick these! If I wanted better audio quality I should prepare to spend 10x the money these cost! 

Wow!
 
Just plugged these into my Audiotrak Im-Amp and they sound great straight out of the box.  Based on the sounds I'm hearing now I'm selling my HD650's and recouping/releasing the funds for other interests.  
 
To my ears, they really are that good.
 
I have a BIG head and found the clamping force of the HD650's rather tight but the HD-668B are comfortable from new.  I might get some plushy pads for an AKG or something to reduce the sweatiness the faux leather pads will no doubt induce.
 
SOUND: Straight out of the box they have a more complete sound than the HD650's.  Maybe its the lack of the Sennheiser 'black' veil?  I think its probably a slight lift in the mid-high frequency range.  But thats fine by me as the so called 'telephone band' is where we as humans are most sensitive.  Bass has been said to be light but I put this down for the fuller mid-highs.  
 
Insight is incredible, given the price and obvious effect it has on build quality.  On the first 2 or 3 songs i played I noticed things I'd not heard before.  Notes played on 'real' instruments begin and end just as you would hear a real instrument to do.  Vocals never seem to push into sibilance which I found an issue on some recordings with the HD650's 
 
As noted above, these are good enough for me to have sold my HD650's  
 
BUILD:  Lots of plastic, but are 'high end' phones really any different?  Not really.
 
My only real bugbear is that the cable options are rather limited as the HD-688B have a 3.5mm jack on the left hand cup and you have to connect a cable from there.  Sure its easy enough to make one up but I'd like to be able to wire straight up to the driver.  Never mind - for £35 inc shipping I cant really complain so I'm off to listen to them again.
 
GIANT KILLER? Maybe, maybe not.  But good enough to leave the £300+ phones alone for a good long time.  
 
Lets call them 'THE BEST ALTERNATIVE'