Step forward Harman Kardon. A US company with a reputation for innovative design and solid engineering, they also have a secret weapon in the cause of developing a high performance Bluetooth headphone. As part of the considerable Harman Group, they also have access to dedicated headphone designers and manufacturers AKG. With this useful resource behind them and considerable experience with Bluetooth Audio in the rest of the group, the chances of them producing something good seem pretty strong. The result of this hard work is the BT over ear APT-X capable Bluetooth headphone, yours for £220.
The BT is different in a few subtle but important ways. At first glance, the effect is retro - the leather headband separate from the metal arch that mounts the drivers and the square enclosures suggest something from the past. Look a little closer and there are other touches that are absolutely contemporary. The driver enclosures are mounted on a clever semi floating mount that allows the earpads to move a few degrees on the vertical axis for additional comfort without having to fit a complete extra hinge to add mass and bulk. Above the earpads themselves, the exposed hinges look and feel superb. You make mock me for getting excited about a hinge but it is part of an overall attention to detail that sets the BT apart.
The result is a superb design. Compared to almost every other pair of headphones that have passed through my hands recently, the BT manages to look elegant and smaller than it actually is. Comments from various visitors have been positive as well. It isn’t a fashion statement, simply a considered attempt to build the most compact and elegant surround to the working parts of the headphones which is in turn constructed out of high quality material. I think it is fantastic.
Internally the BT uses a pair of 40mm dynamic drivers of an unspecified material. These have a claimed frequency response of 16Hz to 20kHz which seems slightly ambitious although the roll off at the lower figure isn’t given. The drivers are set a fair distance back from the ears by the standards of portable headphones and are behind a solid cover that should help them survive life on the move.
The left enclosure houses the Bluetooth receiver and attendant controls. The BT is Apt X capable so formats up to and including FLAC and ALAC can be handled without requiring compression and the more normal portable formats can be handled without issue and it is backward compliant with older types as well. Press the small button on the underside to activate the Bluetooth receiver and the HK should show up in your device menu. Pairing was swift and stable with the three devices I tried it on. Harman Kardon quotes the battery life at being 40 hours which should be enough for most sane requirements you might have.
The good news is that the BT can also be used as a conventional wired headphone even when the battery goes flat. A 1.4 metre cord is supplied allowing you to keep using the BT when out of charge or when connected to a non Bluetooth device. The cord is reasonably thin and unobtrusive but the only anomaly (and slight annoyance) is that the socket that terminates on the BT is a 2.5mm rather than more standard 3.5mm jack. This means you cannot exchange cords with an aftermarket one so don’t lose it! A charging cord is supplied that goes from the same 2.5mm socket to a USB connection. You cannot listen and charge at the same time which is slightly annoying but the battery life is long enough to ensure that this shouldn’t be too great a problem.
The fit and finish of the BT is excellent. The materials used reflect the quality of the design and in the balancing act between lightness and solidity, the BT comes out pretty well. Everything feels solidly assembled and the cushioning on the earpads as well as the matt backs all give the BT a perception in keeping with the asking price. A set of small and large earpads are supplied which is a nice touch and there is also a (slightly effete) leather holdall for when you aren’t using it. Compared to the exhaustively specified PSB M4U2, the BT doesn’t have the same level of facilities and toys but it is still well equipped. In terms of portability, the BT doesn’t fold in on itself but it does fold flat and is reasonably compact once it does so.
Unlike the PSB, the BT has no active noise cancelling. The closed design is able to keep most external noise sources at bay but if you are looking for a pair of headphones to consistently use in a noisy environment, you might want to bear this in mind. The BT is equipped with a microphone though so it can make and receive calls using the same Bluetooth link. This means that you can also use the BT as a gaming headset if you want to be the most stylish World of Warcraft player going.
The first big impression is how cohesive the performance is. The BT is extremely even handed from top to bottom and this makes it incredibly easy to listen to for extended periods. This should not be taken to mean the BT lacks excitement - far from it. It simply avoids over emphasising any part of the frequency range which can result in the performance sounding unnatural over time. This is something that headphones generally find easier to achieve than full size speakers but this is still a very well sorted example of the genre.
The larger than usual space between your ear and the driver also lends spaciousness to listening that is something that headphones can struggle with. Garrels’ vocals are placed beautifully in the context of his guitar but it is easy to sense the greater distance to the supporting instruments. Larger pieces manage to have the same confident placement and sense of space which makes for a happy listen.
Tonality and detail is pretty impressive too. The BT is very faithful to the recording and manages to sound believably real with a wide variety of material. Compared to the staggeringly vivid Grado GR8 or even the wonderfully expressive Audio Technica A500X, the BT is slightly “cooler” and less emotional. If you wanted to give the BT more of this performance trait you could use EQ software (such as comes built in to the iPhone) to give it a little midrange lift. This behaviour is not a million miles away from the AKG K540 that featured in the recent group test and suggests that the company design philosophy has migrated to Harman Kardon.
In an absolute sense, the BT doesn’t have the most seismic bass. The low end is fast and detailed but compared to the PSB, it doesn’t have the same punch with really low notes. This slight lack of heft does however give the BT a perceived sense of speed and timing that is very likeable. I personally value this musical agility highly but if you want to rattle your skull, you may find that it doesn’t have the necessary grunt to do this.
The BT is easily able to reap the benefits of lossless audio and also benefitted from the Furutech headphone amplifier as well. Compressed audio holds up well however. Spotify sounds great and many internet radio stations are enjoyable too. If you compress your audio much beyond 192kbps, the BT will start to reveal the limitations of the compression though and material like YouTube can often sound really rough. This isn’t a flaw of the BT so much as a real world limitation of a revealing headphone.
Disconnecting the cord and switching to Bluetooth and the good news is that the fundamental behaviour of the BT doesn’t change. This is still a very capable headphone and there is much to be said for being able to commute or move around a crowded space without a cord running down the side of your person. What is less pleasing is that performance does suffer slightly. When the speakers are on but not playing any signal, there is the slightest sense of an electrical pulse and background noise. At anything other than whisper quiet listening levels this isn’t an issue but there is a sense that the dynamics are slightly impaired in comparison to passive use.
Judged against other Bluetooth designs however, the BT is still a very capable performer. The connection is quick to establish and seems very stable. Harman Kardon claims that the range is 25 feet and in practice you can stroll a fair distance from the source device without interference or dropout. Three small buttons on the rear of the left earpad give you volume and basic play/pause/skip functions and again these worked well with both iPhone and Android. Call quality is a slightly more mixed bag. I found that it was very easy for me to hear the person calling but it was less easy for them to hear me in turn. I don’t think that there is any problem with the quality of the microphone but it is a fair distance from your mouth when you are wearing them and if you are in relatively noisy environment, it will be picking that up as well.
The BT is pleasingly comfortable in use. The relatively light weight and separate headband and headphone band are features that make the BT easy to have on your head for long periods. The actual amount of physical traction that the BT exerts on your head is less than some other portable designs. This is a mixed blessing. On the plus side, they don’t dig into your head or squash your ears but equally they are not really suitable for use in more strenuous activity which is a shame because the lack of connecting cable would otherwise make them excellent. After some time with the BT, I am something of a convert to the square earpad. It looks like it would be less comfortable than a round design but it actually encases the ear really well.
- Superb industrial design
- Accurate and revealing sound
- Comfortable and convenient to use
- Not quite as accomplished over Bluetooth
- Slight lack of bass depth
- No noise cancelling
Harman Kardon BT Bluetooth Headphone Review
The competition is fierce though. An extra £80 buys you the PSB M4U2 which is one of the most complete headphones I have had the pleasure of using at or anywhere near the price. The BT has to give ground to the useful features of the PSB including that excellent switchable noise cancelling system. Whether the BT is a viable challenger to the PSB comes down to whether you want Bluetooth and if you are as attracted to the styling and materials as I am. The PSB is the logical choice but the BT is a wonderful piece of industrial design that puts up more of a challenge than you might expect.
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