The Sennheiser HD 598 is one of Sennheiser’s low-/mid-range open back headphones. They’ve been on the market for a long time and have been extensively reviewed. Sennheiser offered to send me one, and it seemed senseless to turn it down.
This review is being written after having spent a week and a half with them, and I am able to audition them for 2 more, so I will write updates and revisions to this as time progresses if I feel a necessity to do so.
Fit and Form
These came to me in their standard packaging, which includes the headphones, a 3 meter cable with a specific locking mechanism that terminates in a 1/4” connector, and a 1/4” to 1/8” adapter. These headphones do not come with a carrying case, but as they have no substantial folding mechanism and are open-back, that didn’t come as a detriment to me. These are best and pretty much only suited to home use, in my experience.
I expected to be turned off by the colorway after only having seen them in pictures, but in person, I was surprised to really like them a lot. They aren’t ostentatious or glaring and come across as different, but subtly so, in the midst of a very “black and silver”-saturated market.
The headband is wrapped in a soft, malleable plastic material with “Sennheiser” embossed on top. The headphones sit comfortably and distribute weight well. I didn’t have any comfort issues while wearing them for extended periods of time. The ear-pads are soft, plush, and made of velour. I didn’t experience any sweatiness or excessive warmth during use; however, on days where my skin was particularly dry, I did experience a little bit of itchiness around the front side of the ear-cups.
The (estimated by Digital Trends, no information on Sennheiser’s spec page) 40mm drivers are angled such that they point more directly into your ear canal, a technology that Sennheiser dubs “Eargonomic Acoustic Refinement” or “E.A.R.”
I will admit that with the 1/4" to 1/8” adapter on, the connector end is almost obscenely bulky, but given that they are mainly suited to home use, this wasn’t a real issue in use. The cable itself took a few days to straighten out, but is substantial and flexible. Although it is too long for portable use, I really do not see these used as portable cans, so it wasn’t an issue. The connector on both ends is high quality and inserts well without any phasing or disconnection.
I really enjoyed these headphones for at-home use. Although they don’t overemphasize any frequency range, they slightly emphasize mids in general, particularly the lower section of the mids. They don’t lack bass, but these won’t knock your socks off or stop your heart with their bass presentation. The treble is airy and open without sibilance and lacks any grating or unpleasantness. I found that they performed best with acoustic, instrumental, and vocal-centric music, but they remain close enough to neutral to do well with most any genre that you throw at it, aside from the most bass-reliant music.
The soundstage is relatively wide and deep, as is understandable given that these are fully open-back. Imaging and separation is very good. It was my experience that the imaging on my iSine 20s was slightly more defined, but I don’t really count that as points off, as these still surpassed my mark with flying colors. I also feel it necessary to point out that these headphones got much closer to the ear than most others that I’ve heard. They went plenty far out, but I was satisfied particularly with how close they could get as well. Isolation is obviously minimal and leakage is maximal, but given home use, I didn’t find that to be an issue. Microphonics were pretty much nonexistent, but that’s to be expected.
Songs used: Stadtaffe by Peter Fox, Three Ralphs by DJ Shadow, and Opr by Gesaffelstein
I found the bass in these to be more textured and responsive than anything else. It doesn’t come in tremendous quantity, but I found myself appreciating the detail and subtlety presented. This isn’t to say that they lack bass, but they are a shift from the very common V-shaped sound signature of modern lower end headphones towards a more inverted U-shaped sound signature. Sub-bass is noticeably rolled off, but not absent. It does tend to get covered up in songs with essentially anything to cover it, but I could still hear it, if quietly, in “Three Ralphs” where the sub-bass essentially comprises the bassline. The mid-bass presents well and, again, has good texture and detail, although it is still noticeably reduced compared to, say, the Bose QC 25s.
Key descriptors: clear, detailed, and recessed
Songs used: All This Could Be Yours by Cold War Kids, K.K.P.D. by Christian Scott, and Jolene by Dolly Parton
The mids were unarguably the highlight of this headphone to me. They are lush, detailed, and at the forefront of the sound. This is reflected in InnerFidelity’s frequency response measurements, which show a slight upper-bass/lower-mid hump. Male vocals and instrumentation came clear as a bell with very good detail retrieval and clarity. Female vocals presented slightly further back, but only just noticeably. Classical and jazz came through beautifully as a result of this midrange, with great dynamics and a generally pleasing presentation.
Key descriptors: lush, crisp, and detailed
Songs used: Time by Pink Floyd, Don’t Wanna Fight by Alabama Shakes, and It’s a Long Way to the Top (If You Wanna Rock ‘n’ Roll) by AC/DC
The treble is airy and open. They have great extension into the upper region of the treble without being sibilant or grating. The treble is still slightly recessed when compared to the mids, but provides a general feeling of openness and air to the headphones that I really loved. They are clear, detailed, and delicate.
Key descriptors: articulate, crisp, and natural
Minutia and Miscellaneous
These headphones articulate at the hinge well enough to seal well around my head, but I imagine that there are probably some people who might have seal issues if they have an odd skull structure. However, not my issue, so I can’t say that with full confidence. I didn’t find many quirks with these headphones. They are simple, function well, and do their job without flaunting it, both in terms of sound and in terms of physical form.
I really like these headphones. I spend a lot of time with headphones with a V-shaped sound signature, and this was a refreshing change. The clarity and emphasis on the mids was welcome and made listening to acoustic, instrumental, and vocal-centered music a pleasure. They don’t work as well with more bass-heavy genres, but they don’t flop on them either, thankfully. I found myself spending more time with classical and jazz than usual while listening to these headphones, and enjoying it.
These headphones were provided to me for review by Sennheiser. I am not being paid by anyone to write this review, to endorse the product reviewed, or for the content that I put in the review.
These headphones were powered by an Astell&Kern AK Junior, a Google Pixel, and by whatever soundcard is in the motherboard of my computer.
I have had these headphones for about a week and a half, and I have put about 35 hours of analytical listening through them during that period.