Hands on: Denon AH-MM400 headphones

Stock up on songs: Denon's AH-MM400 will increase your musical appetite

Forget the striking wood cups, the Denon MM400’s sound is anything but wooden, with an immersive soundstage and spectacular stereo separation

A great pair of headphones are tough to take off. If the sound quality is superb and the comfort supreme, you can spend hours stole away in a musical place far away from the bustle of the world around you. If you spend $400 on a pair — the price of the Denon AH-MM400 Music Maniac over-ears we’ve been trying out — you expect them to tick all the above boxes. We set out to determine if Denon’s latest earn their keep.

Denon has gone out of its way to make the MM400’s look either classic and classy, or incredibly old-fashioned, depending on your personal taste. The ear cups are covered in hand carved American walnut, giving a classic, classy style that’s at odds with the plastic and metal that often dominates headphone design.

The Denon MM400 increase your musical appetite, and that’s pretty much what you want from a pair of great headphones.

Opinions about the cans’ aesthetic were varied. Some wrinkled their nose at the very thought of wood on headphones, while others appreciated Denon’s nod to vintage audio hardware. It doesn’t really feel like wood though, more like a highly polished wooden panel you’d find in a luxury car. We love the style, especially combined with the brushed aluminum hangers and the black headband and ear pads.

The hangers have various hinges that ensure comfort of fit, and there’s plenty of flex so they don’t grip your head like a vice, and while my ears did get hot, they didn’t sweat inside them even after several hours of listening. Listening for those extended periods is easy, as these headphones are supremely comfortable. There’s no active noise cancelling, but they do a great passive job of cocooning you in sound. And what a sound it is.

Massive soundstage

Denon has put its own proprietary 40mm drivers inside each cup, made from a carbon and paper composite, and tuned for a flat frequency response that is said to reach up to 40 kHz. We tested them through three different sources: a MacBook Pro using LG’s B&O Hi-Fi Plus DAC, an iPhone 6S Plus, and a Samsung Galaxy S7 Edge playing Hi-Res audio files.

The results are spectacular. They were a little too focused on the midrange for my taste at first, but a quick tweak of the Mac’s equalizer solved that. Go too far, though, and you could easily ruin the incredibly natural sound quality. Vocals in particular shone through, with plenty of power and presence behind them.

Where the Denon’s really shone is the soundstage, and the way they separated stereo effects. The complex stage in Perfume’s Magic of Love was superbly realized, while Boris Blank’s Electrified sounds stunning, seemingly spreading itself out beyond the cans and into the room. Alex Clare’s Too Close stuns with the stereo separation, but highlights that the bass response is relatively neutral, and it needs an EQ adjustment to feel any thump. Use Denon’s own app on your phone to get the best effect, particularly on Android if there’s no standard music app with an EQ installed.

“Can I have these?”

I gave the MM400 to a friend to try out, who wasn’t convinced by the wooden panels, and questioned just how good a pair of headphones that cost a eye-widening $400 could be. Playing his own music through Spotify, after the fifth “just one more,” track, he said, “Can I have these?” The Denon MM400 increase your musical appetite, and that’s pretty much what you want from a pair of great headphones.

There was an odd problem, though. The headphones have a removable 3.5 mm cable, which plugs into the source on one end and the left earphone on the other. Sometimes after plugging it in, sound would only come out of one headphone until the cord was pulled out slightly. It usually cured itself, and was impossible to replicate. Checking some online comments revealed I wasn’t the only one to experience this problem. There are two cords in the box, and one has a plastic inline remote that sadly feels cheap in comparison to the headphones. In an unrelated issue, I also found the headphones uncomfortable to wear with glasses, forcing me to put the arms above the earphones.

The Denon MM400’s may have some wood on the outside, but the sound inside is anything but wooden. It’s alive with detail and emotion, but choosing them over a pair of headphones with a less ostentatious design will be a matter of personal taste. To be sure, if you go for the MM440,  you won’t be disappointed with the sound.


  • Wonderful soundstage
  • Wide stereo separation
  • Very comfortable


  • Connection problems
  • Neutral sound sometimes lacks bass
  • Cheap inline remote

Buy on Amazon

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