Superlux HD668B

Giant Killer you got to hear!

PROS: impressive price/performance ratio, giant killer sound performance, removable cable, replaceable earpads.

CONS: isolation and sound leakage due to semi-open design, not a typical removable cable.

The product was provided to me free of charge by Gearbest for the review purpose in exchange for my honest opinion.

Manufacturer website: Superlux, Available on Amazon and Gearbest.


Even so I have been focusing lately on testing and reviewing flagship IEMs and CIEMs, majority of which cost north of $1k, in this write-up I’m going back to my roots and will talk about sone of the cheapest pairs of headphones I’ve tested to date. Keep in mind these are full size semi-open cans, not another budget pair of in-ears or earbuds where I have seen even lower prices ($5 Monk being the prime example). But still, at $35 or sometime even down to $30, I haven’t heard full size headphones that cheap with a sound that good! Don’t mistake this level of excitement for “OMG, this kills any $500-$1k pair of headphones”, let’s be realistic. But I have no problem saying these $30-$35 headphones have a build quality of other $60-$70 pairs and sound quality that can go head-to-head with a number of full size cans up to $200.

3+ years ago when I started writing my audio gear reviews, my focus was solely on budget earphones, trying to find the next Giant Killer. But you can’t judge something to be a “giant killer” without experience of testing more expensive mid-tier and flagship “giants”. Now, I made a full circle which gives me a more objective point of reference for comparison. I also made an interesting observation about this HD668B model while reading various impressions since its release in 2011. Many of the negative comments I read about it are no longer applicable to this 2016 version, which makes me wonder if Superlux already implemented some of the fixes and improvements based on the received feedback.

The ironic part of this write-up is that I wasn’t even planning to review these headphones and was asked to take a listen to them in addition to something else I requested to review from Gearbest. I probably would have dismissed them just on the basis of how much they cost, expecting the usual of “you get what you paid for”. But I was proven wrong, and now would like to share with you about my experience with Superlux HD668B after spending the last few weeks testing them.

Unboxing and accessories.

Unboxing experience of HD668B didn’t feel at all like I was dealing with a cheap pair of budget headphones. A sturdy cardboard box with a nice cover image, a very detailed spec and a description of the design, and a complete list of accessories with corresponding pictures – the packaging box exterior already carried a message of the product being too good to be true for $35 price tag. But as you know, the writing on the box could be just a part of the overhyped marketing, so without further hesitation I proceeded to lift the cover.

I was greeted with a set of full size cans neatly packed inside of a cardboard insert and other accessories around it. With everything out, I was looking at a generous size soft nylon carrying pouch/bag, two extension cables, 6.3mm adapter, a peculiar cable clip, and a printed manual/guide. The nylon pouch felt neat and durable, branded with Superlux name. I consider adapter to be a filler, but it could come handy with full size headphones when used in a desktop setup. The clip made sense once I attached the cable to HD668B, realizing it does a great job securing the joint if you pull on the wires.

Regarding the cable, it was actually an extension cord. First of all, the whole idea of a removable cable in $35 pair of full size headphones is impressive. But it’s not a traditional cable with 3.5mm male plug on each side. To keep HD668B earcups slim, Superlux brought out the connector to the outside with a male 3.5mm plug and a very short extension cable. As a result, you attach the provided “extension” cable to this external connector. Included was 1m short cable, perfect for a portable use, and 3m long cable for other applications. You can also combine them together to form 4m extra long cable to give you more traveling room around the desk.

This “extension” cable idea was quite unique, though it would not be easy to find an extension cable with in-line remote if you need to. But you can also argue that majority of people would prefer not to carry a phone conversation with these on. With connector placed on outside, the earcup housing was definitely slimmer. Also, the attached earcup connector cable is very short with a heavy duty shielding and impressive strain relief. Not 100% sure if the cable clip was really necessary since the mating of the cable was already secure, but it never hurts to add another level of protection.

Design & build.

The first look at HD668B brought back the memory of my recent review of ATH-A2000Z with a similar wire-headband design and 3D-wings. Honestly, I was expecting a flimsy plastic construction, but surprisingly found it to be not bad at all. Starting with a headband, you have minimalistic design with a support of 2 steel spring-wires, assuming one carries a cable going to the connector on the left side. I have an average size head, and it was a bit tight at first but loosened up after a short time of being stretched over the soccer ball.

There is no height adjustment like in traditional full size headphones, and instead you have soft foam “wings” on a spring metal wire which self-adjusts as you put headphones on. This could be hit-or-miss with some people who have big head or curly hair (the last comment actually came from my wife). For me personally, it works quite well since I’m already accustomed to ATH-R70x and ATH-A2000Z, both of which have a similar “wings” headband support.

HD668B next to ATH-A2000Z

Though the headband spring-wire felt solid, these wings felt a bit flimsy in comparison, especially a thinner wire attachment – just have to be more careful when taking these headphones off you head. Closer to earcups, the headband wires are held together with a plastic joint piece on each side, kind of reminding me of “y-splitter”. These pieces look to be replaceable, if needed, and made of a solid plastic material. I found HD668B to be relatively comfortable to wear, and with evenly distributed 220g of weight it felt feather light.

Moving on to earcups, here Superlux took a page right out of AKG240. I have no doubt that Superlux engineers were inspired by AKG design, even bringing the connector to outside, though keeping a standard 3.5mm TRS plug for “extension” cable attachment. The back of earcups also has a similar to AKG circular vents, intended for a semi-open back performance. The inner middle part of earcups does pivots to adjust around your head, and it works quite well. The pleather earpads are easy to remove and to replace, especially if you want something softer. Since the earpads look universal and stretch over the top of earcups, I’m sure replacement alternatives won’t be hard to find.

The included original pleather pads are OK, but they do get a little hot after extended use. It definitely makes sense to experiment with different earpads to hear how they affect the sound. Just like eartips of in-ear monitors, you can fine tune the level of low end extension and impact as well as being able to control the top end. In addition, once you remove the earpads, you can also experiment with different dampening foam materials to figure out how it affects the sound. Here you will find plenty of room for modding experiments.


The fit


Page 2: Sound analysis, sound comparison, pair up, and conclusion.

2 thoughts on “Superlux HD668B

  1. Hello Sir!

    I purchased these based on your excellent review but wondering how do you tell if it’s the original or 2016 version?



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