Denon is a storied company with a historically interesting technical position stemming from its early partnership with Columbia Records. Denon was both a recording company and a hardware producer from its early days. This kind of business integration arguably makes sense, with Sony as the current exemplar of the approach (accomplished via acquisition). In the U.S. key companies like RCA were not able to sustain excellence across such a wide front, but Denon—at least from the perspective of audio enthusiasts—created some very high quality products over time. This was especially true of phono cartridges and other products related to recording and LP production.
It is hard to say whether the ongoing recording arts culture at Denon is responsible for the AH-D5000, but the idea seems credible since Denon has built something special in these headphones. At the specification level, the 5000s appear to be conventional headphones with a twist or two. They are sealed back, over the ear types, with 50mm drivers. Things depart from convention slightly when we get to the driver material, which is microfiber. And the driver housings are made of mahogany, with reference to its use in musical instruments (a reference that apparently appeals to the Japanese but seems inscrutable to more logic-constrained Westerners who think of instruments and transducers as being fundamentally different).
Despite this minimal story line, the AH-D5000s have developed something of a cult following. I’ll try to shed some light on why below.
Consider this headset if: you long for headphones with rich, musical bass and yet refuse to give up mid-range and treble transparency. Vivid, engaging tonal colors are the AH-D5000’s greatest strength.
Look elsewhere if: small colorations offend you, or if you cannot tolerate even small traces of high frequency brightness.
Ratings (compared to similarly-priced headphones)
The most obvious, hit-you-over-the-head aspect of the 5000s is their bass. The 5000s have strong bass that goes unusually deep for a headphone. After weeks with the 5000s, I’d say they have a bass bump, judged against live sound. But so far I'd say it is a pretty artfully judged bass bump that doesn't get in the way of the music. Compared with headphones (many) that are somewhat reticent in the bass, the Denon version of bass generates a sense of life and punch that is welcome on a lot of material. Put differently, if you like bass and feel cheated when speakers or headphones are a little rolled off, the Denons could be your cup of tea.
To be clear, while the sound can get a little heavy on the bottom with the AH-D5000’s EQ curve, the bass doesn’t get thick and inarticulate. Bass boost can be more articulate in headphones because you aren't dealing with (as many) unpredictable resonances. You can hear this in the Denons, which have much more bass definition than a speaker would with some low-end boost. These are bass-lovers’ headphones.