A good pair of headphones can make all the difference, both in recording and in evaluating your mix. Paul White lends an ear to a pair of AKG's newest, acoustically open headphones.

Have you ever wondered why people don't just mix all their music on headphones? After all, it would reduce the amount of environmental noise considerably and would completely eliminate the need for acoustically treated control rooms — it sounds like the ideal solution! Unfortunately, though, headphones behave rather differently to loudspeakers in several key areas, and, as most music is optimised for loudspeaker playback, relying solely on headphones can be very misleading (see box).

AKG K500

AKG's K500 is an open headphone, and fits over the ear rather than resting on it. This type is known as a circumaural headphone, and the padded circular cushions are made from an open-weave fabric known as pique, which allows the skin beneath to breathe. These cushions are attached to a lightweight plastic disc which has an open plastic grille at the centre to allow the sound from the transducers to pass through unimpeded. A nice touch is that the cushions attach to the main body of the headphone via a simple bayonet fitting, which makes them easy to remove for washing or replacement. Care has been taken to minimise the number of reflective surfaces inside the phone, especially in front of the ear, which could upset the stereo imaging.

Removing the cushions exposes the diaphragm assembly, which is around 30mm in diameter including the surround. This is protected by a moulded plastic structure which is largely open to allow the sound to pass freely. The diaphragm is essentially a dome-shaped, transparent structure (probably Milar or a derivative) driven by a copper voice coil; hi-fi enthusiasts might be pleased to note that the 3m long feed cable is made from 99.999% pure, oxygen-free copper. According to AKG, the diaphragm shape was designed with a special surround which is purported to minimise the breakup modes which occur when different sections of the diaphragm vibrate in different ways, rather than the structure acting as a true piston.

The outer section of the basket is fabricated mainly from perforated metal, and with the headphones worn normally, the sound from the outside world passes through with very little change. Comfort is important with any headphone, and this one is held onto the head using a twin wire headband with a simple but very effective self-adjusting leather top-cushion. The captive lead emerges from the left phone and appears to be terminated in a gold-plated, quarter-inch stereo jack.

However, closer inspection reveals that the jack screws apart exposing a 3.5mm stereo jack of the type that is used with Walkmen and other consumer stereo products, which is a neat touch.

The overall weight of the phones is only 240g, not counting the cable, and I found them relatively comfortable and cool in use.

"The initial impression is of a very uncoloured, clear sound with plenty of detail."

The Sound

The initial impression is of a very uncoloured, clear sound with plenty of detail. Particularly surprising was the quality of bass, especially when you consider that these are open phones which, in general, tend to produce less bass than enclosed types. In fact the frequency range is quoted as being from 15Hz to 27kHz, and while the bass doesn't actually knock you about, it is very even, and low bass guitar, bass synth and kick drum sounds are recreated quite accurately without being overemphasised. Furthermore, the relative level of the bass end doesn't change significantly when the phones are pressed closer to the head, which bodes well for consistency between users.

Comparing the sound in the phones directly with the same material played over a pair of ATC SCM10 monitors, the tonal balance was not seriously dissimilar, though I felt the headphones were just slightly flattering to the top end of the spectrum. The feeling of bass energy was reasonably consistent, though headphones never produce such a solid impression of bass, regardless of how loud you turn them up. You can hear the bass perfectly but you never get to feel it, and I guess that is down to the fact that loudspeakers affect the whole body, whereas headphones couple only with the ears.

Should you for any reason be dissatisfied with these headphones, you may be pleased to know that they have been designed so that they can be disposed of by burning without releasing toxic fumes into the environment!

Opinion

Though these are not cheap headphones, they come over as very accurate and are not too sensitive about exactly how they are worn. They cover the entire audio spectrum very smoothly, and their ability to resolve low-frequency detail is admirable.

The stereo imaging ability is what we have come to expect from headphones, in that left/right positioning can be judged with a high degree of accuracy, but the sounds still appear to originate in or over the head rather than in front of it. This is not a fault of this particular headphone but rather a characteristic of headphones in general, and you soon learn to live with it.

As a tool for listening to a mix in a very analytical way, these are amongst the best headphones in the £100-150 price range I have tried. They really allow you to get into a mix rather than listening to it from the outside, making it easy for you to take a mental stroll around the stereo soundstage, effects positioning and suchlike. Distortion or undesirable harshness also shows up like a sore thumb, enabling problems to be rectified before things have gone too far, and should you get fed up of mixing, they're also first-rate for listening to your record collection! I've tried out many different types of headphone over the years, and this is one of the best I've used in terms of musical honesty. I still wouldn't want to do a complete mix without double checking on loudspeakers at some stage, but the K500s could be used for the majority of a session with complete confidence.

For those needing a slightly cheaper pair of phones, the AKG K400s offer a very similar performance, the difference being a slightly less extended bass response, but as this still goes down to 20Hz, there's nothing missing! In a subjective comparison, I must confess that I could detect little difference at the bass end, and to me, the cheaper K400s sounded very slightly smoother at the top end! Both models are excellent and I'm seriously tempted to retire my faithful old AKG 240s in favour of their newer counterparts!

Further Information
AKG K500 £130.55; K400 £109.99. Prices include VAT, and also a 10% surcharge which AKG regret they have had to add to all their prices, as have a number of manufacturers, because of the current weakness of Sterling. AKG plan to remove the surcharge when the exchange rate improves.

AKG Acoustics Ltd, (Contact Details).