Denon AH-MM400 review

Walnut-finished with serious audio quality

Denon AH-MM400
Walnut-finished with serious audio quality

TechRadar Verdict

The Denon AH-MM400s are a really impressive pair of headphones. They're solidly built and comfortable to wear, and are able to deliver everything from soaring vocals to punchy bass in superb quality.


  • +

    Great all-round audio experience

  • +

    Well-built, well-designed chassis

  • +

    Decent price


  • -

    The walnut finish will be divisive

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Denon is no industry lightweight when it comes to headphones, but we've spent very little time covering its recent offerings. These Denon AH-MM400 cans, though, have demanded we sit up and start paying attention again.

Now, your first reaction to seeing that American walnut finish is probably either going to be one of abject horror, or a creeping sense that maybe your ears would look better cocooned in wood.

Chances are there's little middle ground between the two.

In a world where pretty much only black headphones get bought – outside of the Beats ballpark – it's a fairly brave move for Denon to be flirting with such a divisive look for its high-end headphones.

But it's also indicative of Denon looking to a more mature audience for these more audiophile-friendly cans than the sort of people who hang on Dre's coat-tails with his red, white and blue Beats.

Denon AH-MM400

Build quality

Those walnut earcups are connected to a robust, though impressively lightweight, aluminium frame. There's a lot of movement in the chassis, so they can fit comfortably on different shaped skulls, but there's still a very definite feeling of solidity.

The headband isn't the most plush or padded you'll ever wear, but the design is comfortable and still manages to hold onto the head without a fatiguing crush around the ears.

It should be noted, though, that I do have rather diminutive ears, and so I found the circumaural design perfect for me, but if you have larger lobes then you might find the MM400s a little too tight for comfort.

The MM400s come with a detachable cable as standard, and two different versions in the box. You can have the straight audio cable, or one with an inline microphone and controls to plug into your mobile phone.

Inline remote

It's a neat touch, especially coming as standard, and it makes the MM400s a versatile option to fit in with your daily life, as well as for kicking back at home, closing your eyes and really listening to music.

There's also a 6.35mm adapter to jam into your amp at home.

The MM400s don't feel like the sort of headphones that are going to fall apart any time soon. The build quality is truly excellent – which is a good job considering these Denon cans cost $319 (£195).

That's not an entirely unreasonable price tag, but it puts them in direct competition with Sennheiser's Momentum 2.0 headphones.

Denon AH-MM400

Aural performance

But the comparison with such a outstanding set is a fair one, considering what Denon has done with the MM400s – and the comparison might even come out slightly in favour the Denons.

The AH-MM400 headphones have an incredibly broad range to their frequency response. With a range of between 10Hz and 40,000Hz there's a great deal of detail to the audio you can get out of them.

The consensus is that the human ear is only really capable of processing sound between 20Hz and 20,000Hz – but that doesn't mean the audio we can hear isn't shaped by sound frequencies we might not be able to discern overtly.

By comparison, the Sennheisers are rocking only a 16Hz-22,000Hz range.

That breadth of frequency response, as well as the proprietary 40mm dynamic drivers Denon has kitted its MM400s out with, gives them a beautifully rich, deep sound. Even listening to sub-CD quality audio on Spotify gives a great, detailed sound.

Denon AH-MM400

The clarity at the low end is really impressive. There's no lack of power to the bass, but it's tightly controlled and not overwhelming, and doesn't bleed into or muddy the crispness of the mid-range. It feels natural, not forced, and has a definite warm timbre.

Listening to strings or woodwind through the MM400s sounds glorious – you can really hear the subtle nuances of the physical instruments. And at the other end of the scale they handle vocals with aplomb; there's no harshness to the high-end notes, and that same aural clarity means you can hear all the tonal inflections in an artist's voice.

And even though the MM400's are rocking a wood-clad, closed-back design they still manage to recreate an impressively wide soundstage.

We liked

From the sound to the build to the overall design, the Denon AH-MM400 headphones just ooze quality, like a bottle of Patron Anejo with a dodgy cork.

The audio those 40mm drivers produce is as beautifully controlled as it is deep, natural and warm. The MM400s haven't been tuned specifically to cater to any one facet of music in particular, and sound great no matter what you're playing through them.

And the robust aluminium chassis sits tightly, but never uncomfortably, around your head.

Denon AH-MM400

We disliked

This is where things get a mite tricky – finding something we don't actually like about these solidly impressive cans.

The only reservations we'd have would be on a purely aesthetic basis – that walnut finish is only ever going to be divisive. But when you're listening to them, not looking at them, you'll quickly forget any misgivings you might have about how you look.


Denon's AH-MM400 headphones really impress. They're not being aimed at any one demographic in terms of musical preference, able as they are to cope with soaring vocals as well as punchy bass.

They do just miss out compared with the more expensive Oppo PM-3 headphones in a straight fight on separation and complete audio detail, but at this rarified end of the audio market the differences are marginal; you'd have to listen hard to discern where the planar magnetic drivers of the Oppos pull ahead of the standard dynamic drivers in the MM400s, but audiophiles will be able to tell.

But that doesn't stop the MM400s from being a lovely pair of headphones, with great, natural sound and a warmth of tone that easily justifies their price.