Superlux HD668B featured

Superlux HD668B review – Unbeatable Value

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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.

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.

Available at:

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  • Punchy, articulate bass
  • Clear and detailed sound
  • 2 cable extensions included
  • Price!
  • Stock earpads are a bit thin
  • 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)

 Superlux HD668B box

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.

Superlux HD668B box open Superlux HD668B accessories

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.

Superlux HD668B full Superlux HD668B earcupSuperlux HD668B portrait

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.

Superlux HD668B earpad


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?

Superlux HD668B plug

Superlux HD668B cable


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

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.


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.


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.


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.


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 side view

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.

Available at:

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Founder of Prime Audio
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Ken Starks
4 years ago

Living on a retirement income, my audiophile equipment days are over. Having at one time a 30K Phase Linear system, I got used to extremely good sound. So when I got these for a birthday present, I kind of put them to the side, as they didn’t feel as if they were really of any quality at all.

Oops. Books, covers and all of that.

I also have a set of Senni’s that my wife picked up on sale…like I’m gonna spend 200 plus on headphones. Except for the closed vs partially open difference, the Superlux set performed just as well, in fact better in the mid ranges. This is an excellent headphone. Don’t let the low price chase you off. You’ll be extremely happy with these,

5 years ago

Its been a few years since release but I still struggle to find something else to recommend other than these at the sub $40 price, the price-performance ratio is just superb

haven’t heard nary a whisper on the supposedly new HD688/687 from Superlux though, those might be good

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