Kef M400 full review

Following on from its impressive M500 headphones, Kef has launched the cheaper and more colourful M400 on-ear headphones. Here's our Kef M400 review. See also: 20 best headphones.

You might be waiting for Kef to release some over-ear headphones but for now the M Series headphones are either on-ear or in-ear. The Kef describes both pairs as over-ear on the website but we view them as on-ear since the ear isn't surrounded.

We were thoroughly impressed with the flagship M500 cans and therefore keen to see what the M400s can do at a lower price point.

Kef M400 review: Price and design

A pair of Kef M400 headphones will cost you £199 and while that's still a fair chunk of money, it's £50 cheaper than the M500 when talking about RRP. An issue here is that Amazon has the flagship model at a cheaper price, just £194, unless you want the newly released all-black or all-white colours. Until the price of the M400 model drops there is a value for money issue here.

A key rival for this type of headphones is Bowers & Wilkins' P3 which are very similar and have an RRP of £169 - you can get them on Amazon from £96 if you get the red colour.

Kef has stuck with a similar design when it comes to the M400 headphones. They clearly look like the recognisable M500s but in a slimmed down way. Everything is a bit smaller, thinner and lighter (just 175g) which may suit your needs better than the flagship model.

Kef M400 colours

The M400 headphones are a bit more fun and lively than the M500 by being available in four colours. You can choose from Deep Black and Champagne White but also Racing Blue and Sunset Orange. We especially like the blue option and the fact that the headphone jack comes in a matching colour.

As we found with the M500, the cushions on the headphones are extremely comfortable using memory foam covered in sweat resistant protein leather. There's a light amount of pressure on your ears and the ball-joint on the back of the ear pod means it essentially self-positions. The headband is stiff to adjust but this is actually a good thing once you've found the right position for your head.

Kef M400 headphones folding design

Build quality is still excellent with a combination of aluminium and leather. The headphones fold in on themselves and a carry case is included in the box.

Kef M400 review: Sound quality and features

As well as the carry case, a flight adapter and a 1.3m detachable cable with in-line controls and mic is included in the box. The in-line control is for use with iOS devices primarily but you can still pause, play and skip on Android using the middle button (tap or double tap).

Underneath the shiny aluminium exterior is a 40mm full-range driver; the same size as found in the M500s, although not the same entirely. This is good work considering the more compact design. They also use a very similar acoustic tuning plate but there's no sealing ring so they do leak sound a fair amount which is probably the main issue with these headphones – and even then, with the kind of ambient noise you get in an office it's not that noticeable.

Kef M400 specs

The 40mm neodymium driver and copper clad aluminium wire (CCAW) voice coil result in some impressive waves. As we've found with all the Kef headphones we've reviewed, the experience is well-balanced, crisp and defined. They lend themselves well to a wide range of music genres and long listening periods.

Tuning-wise, we've found the M400s to be geared towards the mid-range while the top-end is still bright and nicely apparent. If they are lacking at all it has to be in the low-end with less of a punch for bass lovers compared to the M500s and rivals. Again, it's not a problem as such, just one of the few minor things we could find with these cans – those into the likes of drum and bass might benefit from a pair more focused on big bass.


Kef M400: Specs

  • Driver - 40mm
  • Frequency Response - 20Hz~20kHz
  • Sensitivit - 101.5dB±4dB (IEC-318 at 1KHz)
  • Impedance - 32±15% Ohm
  • Maximum Input Power - 30mW
  • Noise Attenuation -20dB
  • Cable length - 1.3m
  • Connector - 3.5/3.5mm
  • Weight - 175g

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