AH-MM400 is rated 5.0 out of 5 by 4.
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Reference Quality Over-Ear Headphones

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Features - AH-MM400


Reference Quality Over-Ear Headphone


Discover a whole new world of musical enjoyment with Denon's AH-MM400 reference class headphones, which are professionally tuned for a flat EQ and deliver a natural tonal balance that's faithful to the original musical performance.

Designed to look as good as they sound, the AH-MM400 features a fresh European style-inspired design that combines classic styling with a modern touch.

Aluminum Die-cast Hangers

The earcup housings connect to the lightweight adjustable headband via aluminum alloy die-cast hangers that feature resonance-free construction, along with high rigidity for maximum durability. The AH-MM400 also features collapsible earcups for storage in the supplied carrying pouch.

Natural American Walnut Earcups

Featuring hand-carved natural American Walnut earcup housings, the AH-MM400 delivers a superb musical experience, with balanced tonal quality thanks to the resonance-free natural wood housings. A comfortable over-ear (circumaural) design, the AH-MM400 provides a high degree of passive acoustic isolation, letting you listen to your favorite tracks without distracting background noise interference.

40mm Carbon/Paper Composite

Diaphragms with Free Edge and Neodymium Magnets

The AH-MM400 features proprietary 40mm drivers with advanced Carbon/Paper composite blend diaphragms and neodymium magnets along with Denon's exclusive Free Edge technology, which dispenses with the traditional diaphragm surround suspension to deliver extended frequency response all the way up to 40 kHz.

Oxygen Free Copper cables

For the utmost audio fidelity, the AH-MM400 comes with 2 detachable audio cables, both featuring high purity Oxygen Free Copper (OFC) cable technology. One cable features a built-in microphone along with a remote control for volume, track selection and smartphone control. The other longer cable is provided for connection to other devices, and both cables feature gold-plated connectors.

Denon Audio App

Download the free Denon Audio App (available in iOS and Android versions) to your smart device and enjoy the ability to custom tailor the sound via the 5 band equalizer. Choose the Flat mode for linear tonal balance, or select any of the 9 available custom EQ curves. Or, choose the Manual mode and adjust the tonal balance to your liking.

There are also 3 adjustable DSP modes: The Virtualizer lets you widen the acoustic soundstage, while the Reverb mode lets you add additional reverberation to dry recordings, and there's also an adjustable Bass Boost mode.

As well, the Denon Audio App includes Tunein internet radio, a free streaming music and audio service that lets you choose from thousands of internet radio stations around the globe. The Tunein service features selections of internet stations by global region, music genres and features locally recommended stations as well.


Specs - AH-MM400


Type Over-Ear

Driver Size 40mm "Free Edge"

Active NC N

Bluetooth N

Colors Wood

Smart Phone Control 3 Button Cable Remote

Denon App Denon Audio

Leather Headband Y

Hanger Construction Precision Aluminium

Ear Cup American Walnut

Folding Mechanism Fold In

Detachable Cable Y

Accessories Carry Case

Downloads - AH-MM400

pdf file
AH-MM400 Owner's Manual

1.66 MB

pdf file
AH-MM400 Specification Sheet

3.40 MB

Reviews And Awards - AH-MM400

Rated 5 out of 5 by from Back to the future... As a previous owner of the AH-D600, I was looking forward to a set that was as good on the inside as it was on the out. These are those. I gave the 600s to my brother cuz, you know, they are BIG. These are just right. I have a big head and little ears... so the cups are not an issue for me. When I first received these (MM400s), I had the notion to hunt down another pair of 600s... as these are breaking in, that thought is leaving me rapidly. For travel, home, tube, solid state, etc. these are just fine.
Date published: 2017-02-02
Rated 5 out of 5 by from Impressive I did not expect this ... I am a headphone guy. I do own around 15 different pairs of headphones from OPPO PM-3, V-Moda M100, Fostex TH-600, Nighthawk, AKG K702 and many more and I really enjoy these portable headphone. I had really nice experiences with the old Denon series (AH-D2000/AH-D5000) but did not like the AH-d600 nor the AH-D7100 but I still took the chance to buy the MM400 and do not regret it at all. They are really balanced with little emphasis on the low notes but nothing too exagerated but it makes for really little to none fatigue even with long listening sessions. I know it might sound "cliché" but I really heard some whistles and bells that I did not hear from any other headphone that I have so their sense of details is pretty good. The folding mechanism is well done and I think that it will last for a long time. I did not really use it outside but it does a fairly good job at isolating surrounding unwanted noises. The clamping force is just ok for my taste, it does not squeeze my skull but they do not fall so easily. Even if I move my head really quick they do not fall nor move too much. There is not a lot of padding on the headband but just enough to make it comfortable and I did not feel any pressure after 2-3 hours wearing it. No need to bring a portable with you as they are easily powered by my IPhone 5s. On the other hand I did hear some little improvements when listening from my Fiio X5 but no "improvement" when used with my stack of Schiit. The only downside (for some people maybe but not me) is the size of the earcups that might be a little too small but other than that I am having trouble finding negative points.
Date published: 2017-01-28
Rated 5 out of 5 by from Great pleasure, very confortable I went to a shop to test the Chord Mojo along with my Philips Fidelio L1 and my Fiio X5 3rd gen. and I quickly notice that I needed a better headphone. I asked for one and I received the AH-D7200 - nice sound but too heavy, too big and too expensive for me also I asked for a cheaper one and I received this AH-MM400. So light, so confortable, sound is very good also and I did not found so much difference in comparaison with to the other one, specially regarding the price difference. Since then, I use it every day at work and at home sometimes during long periods of time, it is connected to my Mojo, itself connected to a tablet running Tidal in Hifi mode and I have a lot of pleasure discorvering or re-discovering albums. I think also that the isolation is just at the perfect level. The cable with the remote control is just for ios and that I do not really understand why but as I use it connected to the Mojo dac I do not really care.
Date published: 2018-09-06
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Q&A - AH-MM400

Where can I purchase the AH-MM400 ear pads? Thank you.

Asked by: khoalety
Hey Khoalety, Please contact our parts distributor @ 866-779-7421. We hope this helps, if not you can always give us a call to have one of our expert technical support team members assist with this and any other concerns you may have. Thanks, Denon North America
Answered by: Denon Support
Date published: 2020-03-19

Can I use a Balanced cable with it?

Asked by: spadafora
Hello spadafora, No, we do not recommend using a balanced cable with the headphones as you may damage the coils. Thanks, Denon North America
Answered by: Ken C
Date published: 2020-01-27

How long are the cables that come with headphones?

Asked by: MattyP
Hello, This would be a 6 foot cable.
Answered by: Ken C
Date published: 2018-05-11

Hi. I own a pair of Definitive Symphony 1 headphones that I use with my 4th Gen iPod in Bluetooth. But I'm a die-hard Denon AVR fan and user, and now a HEOS fan. How do you think the Symphony 1 stacks-up against the AH-MM400? Does it come in black? Thanks

Asked by: H2audiO
Ken C, Thank You for the reply. I just noticed that the AH-MM400 was hardwired and NOT Bluetooth. I could care less for Noise Cancelling. But I do like the idea of the independent EQ app, because being able to add bass and pull mids is conducive to quality metal listening, and that's what I like. Thanks, again.
Answered by: H2audiO
Date published: 2018-03-11

Have avr720s . Purchasing blue tooth head phones when im using them does the home theather speakers still active for other people to hear am hearing challenged . As well does the avr blue tooth transmit and receive thx.

Asked by: Pete202
Hello Pete202, Unfortunately the AVR-S720 will only receive a signal from Bluetooth via a phone, tablet or PC. It will not transmit to wireless headphones via Bluetooth.
Answered by: Ken C
Date published: 2018-02-06

These are by far the best headphone I've ever had. I recently twisted one of the cups and now am only getting sound in one channel. I would like to take them apart to see if a wire got disconnected. I can't find anything online. How do I do this?

Asked by: bern
Hello bern, Go ahead and give us a call, our techs can walk you through anything you need or even a replacement pair. 201-762-6665 M-F 10am-7pm EST
Answered by: Ken C
Date published: 2018-12-26

how's it going today some of the reviews online indicate this headphone is not best suited for someone with large earlobes. can you tell me the diameter of the padding and the diameter of the housings as there is no information on your website. thanks

Asked by: MikeD7
Good evening Mike ! I do not know if you got an answer for your question but I took the measurement for you: Overall size: width: 3 inches and height: 3.5 inches Inside diameter: width: 1.5 inches height: 2.25 inches Those measurements are approximate as I do not have the best tool to measure it but it might give you an idea. In my opinion I could understand some people finding that they rest on their ears but in my case I find it really comfortable but I do have small ears.
Answered by: MaxB
Date published: 2017-01-28
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