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Denon AH-MM400 Music Maniac

Over-ear headphones

Item # 033AHMM400

People visiting (and working on) this site care about music.

People visiting (and working on) this site care about music.

Discontinued item

Item # 033AHMM400

About the Denon AH-MM400 Music Maniac

Headphones as serious about music as you are

People visiting (and working on) this site care about music. A lot. We obsess over it. We can recall exactly where we first heard a song, and find joy in unearthing a hidden musical nuance on the hundredth listen. Denon made the AH-MM400 over-ear headphones for "Music Maniacs" like us. They're designed to preserve both the beauty and the warts of the original recording, without imposing any added "flavoring."

Headphones as serious about music as you are

Picturerd with the Marantz HD-DAC1

As good as the Denon AH-MM400 headphones look paired with the Marantz HD-DAC1 headphone amp/DAC (not included), they sound even better.

People visiting (and working on) this site care about music. A lot. We obsess over it. We can recall exactly where we first heard a song, and find joy in unearthing a hidden musical nuance on the hundredth listen. Denon made the AH-MM400 over-ear headphones for "Music Maniacs" like us. They're designed to preserve both the beauty and the warts of the original recording, without imposing any added "flavoring."

I was lucky enough to get my own hands on a pair and they look as gorgeous in person as they do in the picture. The hand-carved American Walnut earcup housings feel deluxe and serve a musical purpose. They eliminate resonance, giving the sound a clear, organic feel. And they keep external sounds from leaking in — and your music from escaping out.

Effortless comfort and sound

The Denon AH-MM400 'phones sat secure on my head, without clamping too much. Lush padding lined the earcups and flexible headband. They felt so light that, if not for the music, I could've forgotten they were there.

This relaxed fit matches their refined sound, that's tuned to deliver music purely and naturally. My TIDAL lossless streaming service recommended the song "Fama Magni" by Bassekou Kouyaté & Ngoni Ba and the AH-MM400s provided a smooth ride on the crisp, infectious groove. Denon's 40mm carbon/paper diaphragms never strained to play highs or lows, even when tested by the tight, deep percussion and sweet plucking of the ngoni (a West African ancestor of the banjo). Switching gears to the gentile country rock of Gene Clark's "Because of You," the headphones maintained their laid-back, transparent sound, while also delivering powerful bass when needed.

headphones with tablet

Get graphic EQ and TuneIn Radio with the Denon Audio app (tablet not included).

Solid build and connections

While top billing goes to the earcups, the lightweight aluminum alloy sliders on the headband feel substantial too. They're incredibly durable and fold at the hinges to create a portable bundle you can slip into the included carrying pouch. You get two high-quality, oxygen-free cables terminated by gold-plated miniplugs. A 1/4" adapter is included for connecting to a receiver or headphone amp/DAC (like the Marantz HD-DAC1 pictured). For music on the move, one cable includes an in-line remote and microphone for use with an iPod® or iPhone®.

Free Denon Audio app

When listening on your smartphone or tablet, take advantage of the free Denon Audio app for Apple® and Android™ devices. This app features built-in graphic EQ, allowing you to tweak the sound of your headphones for different styles of music. You also get seamless music library integration and access to TuneIn® Radio's thousands of worldwide Internet radio streams.


Product highlights:

  • closed-back design to block out external noise
  • hand-carved American Walnut earcup housings reduce resonance
  • Denon's "Free Edge" drivers are tuned to a flat EQ for neutral, transparent presentation
  • 40mm Carbon/Paper composite blend diaphragms and neodymium magnets deliver music smoothly and naturally
  • lightweight aluminum alloy earcup sliders and flexible headband for durability
  • soft earpads for comfort during long listening sessions
  • two detachable, oxygen-free copper cables included, both terminated with a gold-plated 3.5mm miniplug
    • one with in-line 3-button remote and microphone for use with iPhone, iPad®, and iPod®
  • 1/4" adapter included
  • folding design for compact storage
  • designed for use with free Denon Audio app with custom EQ and streaming radio for Apple and Android devices
  • includes carrying case
  • frequency response: 10-40,000 Hz
  • sensitivity: 96 dB
  • impedance: 32 ohms
  • weight: 10.9 ounces
  • warranty: 1 year
  • Our 60-day money-back guarantee
  • MFR # AH-MM400

What's in the box:

  • Over-ear headphones
  • 54" Straight cord with in-line 3-button remote/microphone (right angled 3.5mm plug)
  • 54" Straight cord (right angled 3.5mm plug)
  • 1/4" Plug adapter
  • Owner's Manual
  • Precautions on the use of headphones

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More details on the Denon AH-MM400 Music Maniac

Mark G.

Features & specs

Fit Style Over-the-ear
Earcup Type Closed
Earcup Width x Height 2.898" x 3.659"
Noise-canceling No
Bluetooth No
Bluetooth Version N/A
Mic For Taking Calls Yes
Voice Assistant Access
Amazon Alexa No
Google Assistant No
Siri No
3.5mm Yes
1/4" Yes
Lightning No
4.4mm balanced No
XLR4 balanced No
2.5mm No
Other None
Frequency Response 10-40k Hz
Sensitivity 96 dB
Impedance 32 Ohms
Weight 10.72 ounces
Cord Length 54" + 54"
Parts Warranty 1 Year
Labor Warranty 1 Year

Product Research


Natural American Walnut Earcups: The AH-MM400 Music Maniac over-ear headphones feature real, hand-carved, natural American Walnut earcups to deliver superior sound quality. They are professionally tuned like a fine musical instrument by Denon's studio acoustic engineers to be resonance-free and acoustically pure, and to bring out minute details of your music. The comfortable over-ear (circum-aural) design provides passive acoustic isolation to shut out background noise so you can listen without distraction.

Drivers: The headphones feature 40mm advanced Carbon/Paper composite drivers with Denon's Free Edge technology. The drivers are designed without the traditional diaphragm surround suspension, and deliver an extended frequency response to 40 kHz. They are professionally-tuned for a flat EQ for excellent performance for all types of music.

Durable Construction: In addition to the American Walnut earcups, the AH-MM400s feature lightweight aluminum alloy precision die-cast hangers. In addition to being highly rigid and durable, the hangers also swivel for maximum comfort and are hinged so that they fold for storage in the supplied soft cloth pouch.

OFC Headphone Cables: The headphones come with two cables--one with an in-line remote and microphone for portable use, and one without a remote. The 54" flexible cables feature oxygen-free copper (OFC) conductors with gold-plated 3.5mm plugs. A 3.5mm-to-1/4" adapter is included for connecting your headphones to home components with a full-sized headphone jack.

In-line Remote/Microphone: The portable cable's in-line remote/microphone is optimized for use with your iPod, iPhone, or iPad. The in-line 3-button remote and microphone can raise or lower the volume. While listening to music, you can control playback by pressing the center button once for play/pause, 2x for next track, and 3x for previous track. Phone controls include answer/end a call, switch to an incoming or on-hold call, put a call on hold, or decline a call. Functions are possible, but not guaranteed, with Android and other devices.

Denon Audio App: The Denon Audio App for iOS and Android is designed to enhance the Music Maniac headphone listening experience with your smart device. You can browse your music library by Playlist, Artist, Album, Song, Genre, Composer, Compilation, and Podcast. The app's 5-band EQ, which requires a $1.99 in-app purchase, provides a graphical equalizer for your music library and streaming Internet Radio. There are 10 built-in EQ presets and 3 adjustable DSP modes: Virtualizer, Bass Boost, and Reverb. You can also enjoy over 70,000 Internet radio stations through the built-in TuneIn streaming audio service. The app is available for devices running iOS 5.0 or later and Android 2.3.3 and up.


  • Type: Dynamic
  • Driver Size: 40mm
  • Input Impedance: 32Ω
  • Sensitivity: 96dB/mW
  • Maximum Input: 1000mW
  • Frequency Response: 10Hz - 40kHz
  • Earcup Dimensions: Width=2.898" Height=3.659" Depth=1.591"
  • Weight: 10.72 ounces

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