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M400 On-Ear Headphones

KEF’s stylishly distinctive new M400 Hi-Fi Headphones combine state-of-the-art acoustic technologies with precision engineering, robust lightweight construction and exceptional comfort.

Designed in collaboration with KEF engineering and Studio F-A-Porsche Design. • Click here to read the latest review of the M400 headphones from
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SKU m400
Product Features

Drawing on KEF’s unrivalled heritage of design innovation in pursuit of the clearest and most accurate sound reproduction, they bring the pleasures of high resolution acoustics to the users of virtually any portable device at an extremely competitive price.

High resolution sound on the move

Seriously cool on-ears with sophisticated drivers in a stylishly compact design that combines lightness and outstanding build quality with KEF’s characteristically accurate, natural sound. Like its highly acclaimed M500 sibling, the M400’s astonishing sound quality derives from KEF’s ultra-light full range 40mm dynamic neodymium driver, which boasts a CCAW (copper clad aluminium wire) voice coil painstakingly tuned to deliver the natural, seductively musical response for which KEF speakers have always been famous: crisp, intricately detailed highs, seamlessly fluid midrange and tight, clean bass.

Precision design

Looking as good as they sound: engineered from cast aluminium with a silky premium finish, folding up neatly for storage and available in four stylishly distinctive finishes. Instantly recognisable by its smooth contemporary lines and striking satin colour finishes, the compact M400 is built to last, with a precision-machined cast aluminium frame that has a satisfying premium heft without being heavy to wear, and is hinged to fold neatly away for ease of storage when not in use. There are four stylish finishes to choose from: Racing Blue, Sunset Orange, Deep Black and Champagne White.

Excellent comfort and noise isolation

Class-leading ergonomics, with memory foam and breathable pads that conform to the ear to exclude ambient noise and ensure comfortable prolonged listening. With high density memory foam covered in soft, sweat resistant and hardwearing protein leather, the ‘race-track’ ear pads assume the shape of the ear to form an effective acoustic seal that prevents leakage, while the robust aluminium frame is engineered to maintain a gentle pressure that ensures a comfortable, secure fit in any conditions, even for long periods.

Fits all your devices

Complementing all Apple and most other digital devices, M400 features an integrated inline microphone and remote control on a detachable cable, allowing you to operate the play functions or switch between calls and music. As the detachable cable has standard 3.5mm connectors at both ends, users can easily customise the connectivity to their requirements. Like other KEF headphones, user safety is assured in line with the CENELEC standard for protection against excessive sound pressure.

In the box

• M400 Hi-Fi Headphones
• Flight adaptor
• Carrying pouch
• Detachable cable with mic and volume control

Compatible with Apple devices

• Click here to learn more about the KEF M400 On-Ear Headphones at
Reviews 11

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Customer Reviews

  1. KEF M400
    Everything I expected. Lightweight and good for travel. Constructed well. Blue color looks great. I rated sound quality a 5 but I'm comparing to my last headphones which were at a much lower price point and certainly do not measure up to the KEF M400. Overall I am extremely happy with the purchase and would recommend

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Frequency Response



101.5dB±4dB (IEC-318 at 1KHz)


32±15% Ohm

Maximum Input Power


Noise Attenuation 


Cable length






** KEF reserves the right, in line with continuing research and development, to amend or change specifications. E&OE. **


Press and Awards
M400 On-Ear Headphone Reviews from | KEF Direct Review
 "... I would consider the M400 as some of the best looking and most comfortable on-ear headphones yet. They’re damn great companions for short travels or a quick music fix down on the street. All they need is your smartphone’s output and they will sound simply good. Not having any flaws is a great achievement."
Year: 2016
Magazine / Issuing Body:
Country: United States
Product: M400
Click here to read the complete review.
M400 On-Ear Headphone Reviews | KEF Direct Review
 "They offer great comfort and top-notch audio, with no worries about batteries. And best of all, they fold flat for easy portability and travel use ..."
Year: 2016
Magazine / Issuing Body:
Country: United States
Product: M400
Click here to read the complete review.
M400 On-Ear Headphone Reviews | KEF Direct Review
 "The M400 strikes a perfect balance of comfort, value, sound quality, portability, and style."
Year: 2016
Magazine / Issuing Body: Sound and Vision
Country: United States
Product: M400
Click here to read the complete review.
Sound and Vision Top Pick Award
M400 On-Ear Headphone Reviews | KEF Direct Review
 "...there are plenty of gorgeous moments to be enjoyed with the M400, which provides balance, detail, and rich warmth at the center of the sound across a wide variety of genres."
Year: 2015
Magazine / Issuing Body: Digital Trends
Country: United States
Product: M400
Click here to read the full review.