When I was offered the opportunity to test the Superlux HD671 closed-back headphones I jumped on it. Why? Well, because the previous Superlux models that I tested punched way above their price points in sound quality and I had no reason to believe this one would be any different.
As it turns out, the HD671 continues the Superlux tradition of providing absurdly high-quality audio at a very affordable price. But at the same time, it brings with it some of the drawbacks that the previous models had, as well as some new ones. So should you be excited about this headphone? Let’s find out.
This sample was provided for the purpose of an honest review. All observations and opinions here are my own based on my experience with the product.
Package and Accessories
Similar to what we saw with the HD-672 (review here) the Superlux HD671 comes in a simple cardboard box (but this time it’s black) with an image of the headphones on the front. On the back of the box is a list of features and specs, plus an image of the headphones in both black and white colours.
Once again we see the triangular cardboard insert with the provided 3.65mm adapter strapped to the top of it and the headphones wrapped around it.
Provided in the box is the same bundle that we got with the HD672, which consists of the headphones, a 3.5mm-6.35mm adapter and a fabric drawstring pouch.
Build Quality and Design
The Superlux HD671 comes in white and black, though only the black version will be available in the US. It sports a simple, lightweight design made up of just a few core components.
Forming the basis of the headphones structure are the 2 flexible rods that reach all the way down to connect to the earcups.
There is a thin PU leather self-adjusting headband that naturally conforms to the size and shape of your head. The earcups are made entirely of plastic which makes the headphones very lightweight and they feel quite durable.
Just like the HD672 the earpads on the HD671 are silicone instead of the usual protein leather. This makes them much more durable and easy to clean. The pads are removable so you should be able to swap them out for a different pair if desired.
The cable is non-detachable which gives me a sad face and its also long at 2.5m. This is a good length for desktop or small studio but extremely unpractical for portable use.
Comfort and Noise Isolation
According to the specs of the headphones, the clamping force is approximately 3.5 Newton’s. If that doesn’t mean anything to you that makes 2 of us!
What I can tell you though is the pressure that the headphones exert on the side of your head is quite light but more than enough to keep them securely in place, even when moving about.
The self-adjusting headband works brilliantly and conforms naturally to the shape of your head. It also has a good adjustment range, suitable for all types of domes.
Now about these earpads. They get hot on your ears pretty quickly as they don’t breathe in the slightest. They cushion your ears really well and are comfortable in that way but those with larger ears may find the earcups a bit shallow.
I find that my ears touch the hard plastic driver covers which can create uncomfortable hot spots after a while. Throughout testing the headphones my ears became more used to it but if you only wear these periodically it probably won’t be the most comfortable experience.
Noise isolation is not great. In fact, it’s well below average for a closed-back headphone. Even with music playing (albeit at a fairly low volume) I can still hear my television in the background. The noise leak is minimal, so people around you aren’t likely to hear your music unless you’re blasting it pretty hard.
Gear used for testing includes the Sony NW-ZX300 and Soundaware M2pro DAPs for portable application. On the desktop, it was my Windows PC running Tidal HiFi and JRiver Media Center and feeding the Topping DX7 DAC.
The Superlux HD671 has an energetic, detailed and balanced presentation. The overall sound signature is fairly neutral with good tonal accuracy which would make it ideal for home studio applications such as mixing/mastering audio and video. It’s also great for pure music enjoyment as well, so long as you’re not sensitive to a slightly brighter sound.
The bass is fast and tight with truly impressive texture and definition. It has a fast attack and decay, making bass notes quite lean with a well-defined edge.
Sub-bass has excellent extension with a very fast rumble but it doesn’t feel very powerful or evoke much emotional response. Having said that, however, for accuracy it is really impressive on a technical level.
The repeated sub-bass notes in “Smartz” by Scarface are clearly audible but they don’t have much physical presence and lack any wow factor. But if you were mastering the track these headphones would be the perfect companion.
There is excellent instrument separation in the Superlux HD671’s midrange but because of its neutrality and the leanness of the bass it can at times sound a bit thin. It has remarkable tonal accuracy for such an affordable headphone and electric guitars are brimming with crunch and texture.
Vocals sound extremely articulated and the clarity is outstanding. Despite the significant peak around 7kHz the HD671 does well to avoid sounding sibilant but it makes no attempt to hide any that is inherent in the recording. At times there is some hollowness to the HD671’s midrange that has a slightly unnatural effect.
I love the way this headphone has equal mastery over male and female vocals. Male vocals have body and richness, while female vocals have presence and vibrancy and all have that fantastic clarity and intelligibility. A kickback to the brilliant Sade seems fitting here, her sultry and sensuous voice in “The Sweetest Taboo (Live)” is reproduced tastefully by the HD671.
Treble notes have great definition and feel light and airy. This area is one of HD671’s biggest strengths. The extension is all there and the timbre is absurdly good from this budget headphone. It’s exciting and packed with detail.
Cymbals sound exciting and lifelike, with a great sheen and natural decay. The 7kHz-10kHz range is boosted and is where the headphone gets its clarity and apart from picking up the occasional sibilance, the treble is presented smoothly.
The soundstage presented by the Superlux HD671 is exceptional for a closed-back headphone (albeit a poorly isolating one). It’s really well-rounded with defined boundaries and the stage size is above average.
Imaging is strong and positioning is precise; the HD672 very clearly lays out the various elements in the recording. Vocals are positioned well in front of the listener, giving ample breathing space without sacrificing any density.
Superlux HD671 vs Superlux HD672
Vocals are more intimate on the HD672; a result of the 671’s smaller soundstage. Strangely the bass on the HD672 is fuller and has a slower decay than the HD671. Likewise, the sub-bass has more gusto on the HD672 which is a reversal of what I was actually expecting.
In fact, everything on the HD672 sounds a bit more forward and more dynamic. From top to bottom the HD671 sounds drier and less musical but it’s something I didn’t notice until I compared the two directly.
If I had to give the HD671 anything I’d say its imaging is a hair better than the HD672 but there’s very little in it. Even its noise isolation isn’t very much improved over the 672.
Superlux HD671 vs Superlux HD668B
First of all, the HD668 requires more power to drive, which is still fairly minimal as this 56Ω headphone can still be played directly from a smartphone.
The HD668B has more sub-bass and mid-bass quantity than the HD671 but it doesn’t have the same definition or texture in its bass notes. The 668B’s midrange is fuller and more natural, even if it doesn’t reach the transparency and separation of the HD671 which sounds leaner from top to bottom. The 671 has more clarity but there’s also a slightly unnatural hollowness to it.
It’s a similar story in the treble too. The HD668B isn’t as crisp or forward in the treble but it does sound smoother overall. The 671’s soundstage is more expansive but at times it sounds a bit like you’re in a large concrete carpark where the sound is bouncing back off the unyielding surfaces.
The Suplerlux HD671 is a good budget headphone that has a lightweight and sturdy build quality. Although the silicone earpads do have some benefits I still think they’ll be a deterrent for many people.
Having said that, they are removable and can be replaced with different earpads but that’s an extra hurdle that people shouldn’t need to jump. I think Superlux should have provided an extra alternative set of pads in the box, especially now that they no longer offer an additional cable.
When it comes to tonal accuracy the HD671 does exceptionally well for a budget headphone and would be well suited to mixing or mastering duties but for casual listening, it can be bright and unforgiving, at least to my ears.