Denon AH-MM400 full review

Denon is very well respected throughout the audio community, namely through their amplifiers and their old 2007 headphone line, with the Denon AH-D2000/D5000/D7000. In 2012, Denon refreshed its headphone line-up with the Denon AH-D600 and D7100, both of which were supposed to replace the older generation of headphones. Unfortunately, due its audio driver changed from leading audio company Fostex and a vastly different look on the D600 and D7100, the headphones were not as popular as the older 2007 line.

Fast-forward to 2015-2016 and Denon have released the Denon AH-MM400, found under the 'Music Maniac' line, which at first glance seems to take after its 2007 predecessors with its wooden cup design and an almost Kef-looking headband assembly design, which looks to appeal to more consumers due to its portability.

Denon AH-MM400 review: Price and competition

The MM400 were initially released at the £349.00 price, but can already be found for under £200 in the UK, a drastically different price tag. We will therefore look at comparing the headphones at the given £196 price tag found on Amazon. To us, its biggest rivals are the Sennheiser Momentum 2.0 found at around £220, the KEF M500 found at around £250, the KEF M400 found at around £200, the Audio-Technica ATH-M50X found at around £125 and even the Sony MDR-1A found at around £120. All of which are headphones that are somewhat designed to be portable and have above average sound quality and design.

At its £196 price tag, the Denon’s do have a lot of competition, let’s see how they fair in comparison to the other headphones out there.

Denon AH-MM400 review: Build quality, design and comfort

Its build quality is absolutely fantastic, long gone are the loose hinges found on the D2000s and the poor headband assembly reported by some on the D600s. The MM400 offer a good combination of looks and functionality, which is something we found to immediately stick out to us. Due to its smaller driver size at 40mm, rather than the D600 and D2000 50mm driver, the overall size of the MM400 is much smaller. This not only affects its sound quality which we will get onto later in this review, but also its portability factor.

Unlike the D600 and D2000 which were near impossible and awkward to take out the house, the MM400 are aimed at portable listeners. This new approach by Denon takes on an increasing trend of listeners who like to take their music on the go, and because of this Denon has made the MM400 smaller and easier to carry, by making the headband tougher against impacts and included the headphones with a fold-up design. This approach means it’s much easier to carry around your Denon headphones in a bag or even within a large pocket. Read next: KEF M400 review.

With this design change, it’s nice to see Denon reintroducing their wood design, by utilising ‘natural American walnut earcups’. We found the finish of the headphone absolutely superb, where the grain of the wood gives the headphones a touch of class and prestige. The same feeling owners of the D7100, D5000 and D7000 had, not only for aesthetics but for sound quality traits wood cups brought to the resonance of their headphones.

Another feature that’s a pleasant surprise is the fact that the headphones come with a fully retractable cable design. Inside the MM400’s package you’ll find two cables, one of which has a remote and microphone which works on almost all smartphones out there. The cable itself is also very lightweight and thin, meaning taking either of the cables on the go won’t be a problem, unlike with the D2000 which caused a huge amount of headache. It should be noted that both cables are terminated by a gold-plated right-angled 3.5mm jack. Within the box you’ll also find a 1/4in (or 6.3mm) jack and a manual.

We found the headphones to be comfortable for short period of listening, but found it to be a little uncomfortable for longer listening session, especially if you have larger ears. This comes from the headphone’s pads which are made out of a foam material, but due to their portability-factor are reasonably thin. The headphones themselves are reasonably light on the head, but don’t ooze quality due to the selection of synthetic/faux-leather, rather than using the premium leather-feel and smell found on other headphones.

Finally, we found its isolation to be decent for a headphone, but not one that would provide the levels of isolation needed in a busy commute. Sound leakage was minimal, but so was its isolation on public transport. We felt the D600 isolated better as they engulfed your ears with its big pads, whereas the MM400 didn’t even go around-the-ear. Due to its 40mm drivers, the headphones might not fully wrap around people who have bigger ears. Furthermore its pads cannot be removed or changed, unlike the older headphone line where they could be easily interchanged.

Denon AH-MM400 review: Sound quality

The sound quality is by far the most important part of this review, where we were very intrigued to see how it would compare to the D600 and D2000 which we had in the office. The D2000 pair of pictured has been modified with D5000 cups, a custom D7000 cable and Lawton Audio pads.

The sound quality of the MM400 is very impressive, given its size and portability. In comparison to other headphones out there, namely the Sennheiser Momentum 2.0, we found the sound to be warmer and a little more pronounced in the lows, where the MM400 extended better in the sub-bass region. The Denon AH- MM400 do sound a little warmer and V-shaped than the Sennheiser Momentum 2.0, which had a greater emphasis on the mids and the highs, rather than the lows.

The burning question Denon owners must be asking themselves is: How does it compare to the D2000 and D600 headphones?

Unfortunately we found the MM400 to simply lack finesse in all frequency ranges. Starting with the lows, we felt the MM400 had more impact in the mid-bass region than the D600s, but lacked that control and extension that was found in the D2000s. This all resulted in a slightly bass-orientated sound which pushed back the headphone’s mids.

Due to a slight emphasis on the mid-bass, the mids sounded a little recessed and a bit pushed back. This means it provided a warmer sound than the D600, but one that was a little too warm and recessed for our liking. Despite the D2000s being slightly V-shaped in comparison to headphones such as the Sennheiser HD650s, it still provided its listeners with a great mids reproduction. The same cannot be said about the MM400, which just lacked that presence in the mids.

Moving on to the highs, we found it again to lack that little extra extension, where the highs would simply roll off and not extend into the high frequencies. Both the D600 and D2000 performed better, where they provided a better sparkle and extension in the high frequencies.

Finally moving on to its soundstage, we weren’t surprised by its sound being slightly closed and narrow in comparison to the bigger 50mm drivers found on the D600 and D2000, both of which provided a better soundstage, instrument separation and placement, and resonance due to a deeper ear cup. Read next: Sennheiser Urbanite XL Bluetooth headphones review.

It’s not to say the Denon AH-MM400 doesn’t provide good sound, but in comparison to its predecessors can’t really compete. It’s also hard to understand why Denon have discontinued both the 2007 AH-D2000 line and the 2012 D600 line, as they not only provide better sound, but are also designed for a completely different audience. The MM400 are clearly aimed for portable users who will not tend to use these foldable headphones with a full-blown amplifier. Whereas the contrast of its older brothers is the complete opposite, where they were intended for home use only and could potentially be taken on the go in a bag.

We feel that Denon are a little confused about their audience, where its most popular headphones came from those wanting home-only headphones and not caring about the portability of their headphones. This could all change in the future, where Denon might surprise us with another headphone which is aimed at home users, but from what we can see on their store and via retailers, the Denon AH-MM400 is aimed to replace the older headphone line.

However, versus the competition of the portable headphone market, the Denon AH-MM400 is definitely one of the best we’ve tested, where its design, build quality and sound quality are extremely impressive. We feel this headphone really fits in well within the portable headphone market, providing a better sound quality over the KEF M400 & M500, the Audio-Technica ATH-M50X and the Sony MDR-1A in almost all aspects. In comparison to the Sennheiser Momentum 2.0, we found it to be a warmer headphone that produced a better bass response, whereas the Momentum 2.0s provide a better mids and highs reproduction, thereby making both headphones sit equally together and only being separated by personal taste. 

On a final note, you'll be able to tweak the sound quality of your Denon headphones through the Denon Audio app found free on the Apple App Store and Google Play Store.

Read next: 20 best headphones of 2016.


Denon AH-MM400: Specs

  • Driver diameter: 40mm
  • Driver type: Dynamic (Carbon/paper diaphragm + Free Edge)
  • Impedance: 32 ohm
  • Sensitivity: 96dB/mW
  • Maximum power input: 1000mW
  • Frequency response: 10-40,000 (Hz)
  • Weight: 310g

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