Sennheiser HD 599 review

It can be hard to find headphones that add bass to music without entering skull-shaking territory, but not anymore. With a foot in the camps of both audiophiles and general consumers, the Sennheiser HD 599 seeks to please many listeners, ranging from headphone to music enthusiasts. Can it pull off this hefty task? We tested the Sennheiser HD 599 for two weeks to find out.

Editor’s note: this Sennheiser HD 599 review was updated on October 10, 2023, to include new charts, the AKG K371 in alternatives, and to answer FAQ.

What’s it like to use Sennheiser HD 599?

Available in a divisive pearlescent ivory and brown colorway, the Sennheiser HD 599 suggests a retro-futuristic vibe. The ivory is almost the exact same shade as early 1990s beige PC towers with a sheen, while the shape and lines are more modern.

Build quality seems average, with a foam headband covered in brown vinyl, and notched size adjustments. The HD 599 is made mainly of plastic and sports removable velour ear pads with 70mm x 45mm clearance for your ears. These ear pads feel like the midpoint between the stiffer, rougher AKG K702 and the deluxe Beyerdynamic DT 900 PRO X. Clamping force feels secure — not tight and not super loose. Aiding in a comfortable fit, each headphone swivels slightly on horizontal and vertical planes, but does not fold. All of this, in combination with the heat-regulating open-back design, means you can wear the Sennheiser HD 599 for hours at a time even in summer.

For a fuss-free experience, you ought to use the Sennheiser HD 599 in a quiet space at home. The long cable allows you to hook it up to your computer or home listening setup, and sit across the room relaxing. You can use the HD 599 for critical listening, but you may find the sound is not studio grade enough to rely on it for accuracy. This is totally fine — most of us listen to music for pleasure and not as our job, after all.

Does the Sennheiser HD 599 have good isolation?

If you want isolation you will need to consider closed-back headphones. Open-back headphones are like the ultimate transparency mode: you hear your environment, and everyone hears your music. You’ll want to listen in your private office or while relaxing on the couch without others around. Most of us do not have ideal environments. Even when I’m home alone, I can still hear the neighbor mowing the lawn through the HD 599 if my window is open.

How does the Sennheiser HD 599 sound?

Paired with the right source material, the 38mm dynamic drivers make the HD 599 sound good. However, the frequency response we measure deviates from our headphone preference curve, which we consider to work best for the majority of source material and listeners. There’s a sizeable volume bump where the low mids meet with the bass frequencies. While Sennheiser imbues the HD 599 with a favorable curve in the highs (i.e., it’s sort of close to our ideal before 10kHz), the exaggerated low-mids and bass can make that added treble clarity and detail get lost, especially above 10kHz.

You can still hear upper harmonics and overtones, but you might find the uppermost octave to be lacking, especially during very complex tracks. It also depends on your source material, because this curve works just fine with some genres like electropop or new wave.

It’s unusual to find a set of open-back headphones with bass exaggeration, as those frequencies tend to get lost with open-back designs. The HD 599 does indeed roll off the sub-bass, but it exaggerates where a lot of bass instruments reside.

Lows, mids, and highs

Listening to The Rock by The Aluminum Group, vocals come through clearly with the keys. The kick drum thumps with a good amount of volume. The bass guitar could be a little louder, especially on the lowest notes. Finally, cymbals and snare suffer from some inaccuracy that makes them slightly “hollow” sounding. For reference, this comparison is against the KZ ZSN Pro X, which has more volume above 10kHz and follows our ideal closely through the mids and bass. In contrast, the male vocals, piano, horns, and strings, which make up most of the song, sound pretty good.

Trying a shoegaze track with high vocals like Sweetness and Light by Lush, the guitar volume seems too loud relative to everything else, while the soprano vocals are overwhelmed by the guitars (even for shoegaze). Cymbals crash too quietly relative to the snares, though percussion overall is at a good volume. Meanwhile, the kick drum is audible, but the bass guitar is far too quiet. It’s really tempting to turn up the volume to better hear parts, though I’m aware I will only hear more guitar. This sound is not horrible but leaves room for improvement.

Should you buy the Sennheiser HD 599?

Not quite audiophile-grade and not quite consumer-oriented in sound, the Sennheiser HD 599 occupies an unusual space where it ticks a lot of boxes, though not all. For the price, it does a good job of feeling super comfortable and has some frills like removable cables and ear pads. Those of us who don’t like “V-shaped” frequency responses, but do like a little more bass and midrange emphasis than what studio headphones offer will mostly enjoy the sound of the HD 599. You would not want to mix music on it, but it’s great for binging Netflix and podcasts.

However, if you don’t live alone or have a room sequestered away from family or roommates to listen in private, the HD 599 has some limitations in its use. This is true of all open-back headphones, but even so, it bears mentioning because the HD 599 is already a sort of niche product. I would not hesitate to recommend the HD 599 for pop music fans, except for fans of Beats-style headphones or folks who want very neutral headphones. Liberal use of equalization will really make this comfortable set of headphones shine a bit brighter.

What’s the difference between the Sennheiser HD 599 and Sennheiser x Drop HD 6XX?

While you might look at the names and think the Sennheiser x Drop HD 6XX is one number higher, so it must be better, you’d be mistaken as these two headphones do not have quite the same purpose. Though nobody can blame you for inferring a similarity through Sennheiser’s naming scheme, the HD 6XX, unlike the HD 599, is meant for critical listening.

In everyday terms, the HD 599 excels at casual music and media consumption, while supplying a comfortable fit. In contrast, the HD 6XX offers a more “flat” frequency response designed for critical listening and mixing audio. You can listen on the HD 6XX for fun as well, but its studio-style sound will be notably more subdued in the low frequencies, even though both headsets have a sub-bass roll-off. The highs, particularly above 10kHz, will be more audible on the HD 6XX as well.

Besides these case use differences, both headphones are open-backed with primarily plastic builds using velour ear pads. The HD 599 edges ahead in comfort, as the HD 6XX can feel tight after an extended session. Both headphones have removable cables but use different connections. While the HD 599 requires a single cable with a TRS 3.5mm locking end into the headset, Sennheiser ships the HD 6XX with a Y-split cable with a two-pin connection to the headphones. The former is actually a less obstructive solution, but harder to replace. Finally, the Sennheiser HD 6XX may need a headphone amp to really access its potential, while the HD 599 does not.

What are some alternatives to the Sennheiser HD 599?

The Audio-Technica ATH-M50x features more bass and closed-back ear cups. It’s suitable for listening to most kinds of music, and it isolates significantly better than the Sennheiser HD 599. The fit of the ATH-M50x is reasonably comfortable, though, not as forgiving as the HD 599. On the other hand, the closed-back design is more versatile in less-than-ideal environments extending its flexibility for $169 at Amazon. You can also try its optional hardwired or Bluetooth-friendly counterpart, the ATH-M50xBT2 ($198 at Amazon).

Keeping in the vein of closed-back headphones, the AKG K371 is one of our favorite pairs of value-to-performance wired headphones. They provide excellent sound, do not require a headphone amp, and they’re not too pricey either ($176 at Amazon).

For an open-back alternative, the Philips Fidelio X3 $139 at Amazonboasts a fairly neutral frequency response, and it’s comfortable for folks with glasses. This relatively accurate-sounding headset means what you hear is basically representative of how the audio is mixed on larger 50mm drivers. Like the Sennheiser, the Philips Fidelio X3 possesses the same limitations of open-back designs, including virtually zero isolation.

Of course, if want you really want are open back headphones with a more neutral frequency response, the Beyerdynamic DT 900 PRO X delivers. The price is a bit more dear ($269 at Amazon) but, it’s more versatile and playback is more representative of your source material.

Frequently asked questions about the Sennheiser HD 599