Sennheiser HD700: Sennheiser with a Sledgehammer
 
Sennheisers of the HD6xx and HD8xx line have a tendency to be fantastic reference headphones with ample soundstage that generally share one (or both) of the following two tendencies: An expansive soundstage with exquisite detail reproduction, or the ability to find their ways into studios as reference headphones for listening, mixing, and editing recorded audio. They also have a tendency to sound veiled at the high frequencies regardless of their analytical nature. The HD700, one of Sennheiser’s high-end headphones, seems to buck this trend; eschewing reference quality for a more “Grado-esque” sound generation. This more “in-your-face” approach has made it one of the most polarizing high-end headphones on the market, and I’m going to write this review as a first impression; primarily focusing on the empirical, and about 20 to 25 hours of “break-in” having been done. (FULL DISCLOSURE: I KNOW THAT THIS IS NOT A FULLY BROKEN IN HEADPHONE.)
This review will focus on the HD700 as a headphone used in the PONO player, and in comparison to my Sennheiser HD598 that have been upgraded with a Moon Audio Blue Dragon cable. I’m going to, as applicable, compare the sound quality, portability, and even how the PONO’s battery life is affected between the two headphones. I will also go over less “audio-important” aspects such as the presentation of the headphones, the cost, and whether the price : performance ratio validates one, or both, headphones in one’s headphone arsenal. Before this review goes further, I’m going to lay out the specs of both headphones.
 
Sennheiser HD598

1. Color: BEIGE / Brown
2. Impedance: 50 Ω
3. Build: Plastic body, faux leather headrest, velour pads, steel ear-grilles
4. Driver Size: 40mm
5. Sound Range: 12hz – 38500hz
6. Weight: 270g
7. Jack: ¼ inch Jack included (Moon Audio Cable has 1/8 inch jack)
8. Head Connector: twist-in 2.5mm jack
9. THD: 0.1% (1khz / 100db sound pressure level)
10. Where’s it Made: China
11. Price and Where I bought it: $120 @ Amazon

 
Sennheiser HD700:

1. Color: Anthracite / Light Gray / Black
2. Impedance: 150 Ω
3. Build: Plastic body, metal earpiece adjusters, alcantara earpads (I think), stainless mesh ear-grilles with visible driver backside
4. Driver Size: 40mm
5. Sound Range: 15hz – 40000hz (-3db); 8hz – 44000hz (-10db)
6. Weight: 270g without cable
7. Jack: ¼ inch gold plated jack, I use a Grado ¼ inch to 1/8 inch converter for PONO use
8. Head Connector: 1 2.5mm click-in headphone connector per earpiece
9. THD: 0.03%
10. Where it’s Made: Ireland
11. Price and Where I bought it: $749.99 MSRP; $425 @ B&H (before coupons and gift cards)

 
With enough variables out of the way to give this review some semblance of science, let’s compare the initial handshake that the HD700 gives. The handshake is also known as the unboxing process.
 
UNBOXING AND FIRST IMPRESSIONS
The HD700 comes in a rather large box with a silhouette of the HD700 on the front, and the slogan “Truly Excite Your Ears” on it. I’m not sure if this means that Sennheiser is trying to make a more “in your face” headphone meant to entice those who feel other high-end Sennheisers are more “veiled,” or if this headphone was the beginning of a new direction for Sennheiser that accepts less “reference sounding” headphones. Anywho, opening the box reveals…. ANOTHER BOX! (albeit a very nice one) This box opens on a hinge to reveal the HD700 sitting inside, surrounded by super soft foam, and the 3m kevlar-wrapped cable is kept in its own separate compartment. It’s not the crushed velvet introduction of the HD800 / HD800s, but it’s also not a handmade-in-Germany, cost-be-damned headphone. It’s one step below, but Sennheiser is still letting you know that this is a serious headphone that’s more than capable of bringing world-class performance without the exorbitant prices of its German superiors. In contrast, the HD598s came in a basic box, with blister plastic around them, but otherwise very well presented for their price point.
 
Removing the HD700s was a bit of a task at first. The foam surrounding the headphones themselves holds them very securely, but I was not expecting the headphone cables to be connected at the initial unboxing. Thankfully, the 2.5mm earpiece connectors were solidly in place, and the box itself was not compromised. I do wonder if this is how it came from the factory, or if it was a return… either way, they work, and they play nicely, so I’m content. The factory cable itself is a 3 meter (about 9.8 foot) long cable wrapped in a kevlar-like cloth. I’m not sure what the wires inside are, but they are extremely flexible and it is extremely high quality. So far, everything about this headphone seems to be up snuff for the $425 street / $750 MSRP. So I began clicking them to get them set up. Initially I tried to eyeball them to my HD598s, which I liked at 4 clicks short of maximum. I lined this up to 6 clicks past the smallest size on the HD700s. Over time, the HD700s broke in, and I found that reducing this to 5 clicks past the smallest size provided a better fit. Clamping force is light, but assured, and does not harm my glasses. Will they move? No, will they clamp? Yes. Will they clamp so hard that they’ll snap the arms off your eyeglasses? Thankfully, no. The HD598s, would clamp hard enough to bend the ear-pieces on one’s glasses, relegating a lot of its listening to glasses-less time. In contrast, the HD700s can be worn for hours with glasses with no ill effects on the glasses’ integrity.
 
My enthusiasm was dampened somewhat by the connector itself. Not due to an issue on the part of Sennheiser; they market this as a high-end, near-endgame headphone, so a long cord with a ¼ jack is justifiable, but why not throw in different cables as well? Quite a few HD700s are pressed into service on portable DAPs, so a 1.5m 1/8 termination, or an XLR balanced cable not unlike the HD800s that was released early in 2016, would be a welcome improvement for increasing its versatility out of the box. (Now ideally, I’d like a balanced cable for my PONO player, since this set of HD700s will see extensive use with it, but that’s such a niche request I can understand Sennheiser not going that route.) The HD598s come with a 3m cable, rubber coated, and also terminated into a ¼ inch jack, but presumably due to the lower impedance and subsequent greater likelihood of being used with a mobile DAP, a ¼ inch to 1/8 inch converter is included. A nice touch, but due to the length of connector that ensues with the HD598, it can put a LOT of torque on DAP connectors, and PC connectors. (NB: 2 of my sound connections were damaged by the HD598s ¼ to 1/8 inch converter mechanism that, when combined with a 10 foot cable, can easily yank connectors right off their solder points…. Be careful.)
 
However, the HD700 required a connection converter of its own, because it did not come with a 1/8 inch male jack. To this end, I put a GRADO ¼ inch to 1/8 inch converter on it. Whereas the 598’s included converter was a direct plug, the GRADO plug had a small amount of cable on it, which helped to relieve some of the torque-factor that was inherent in the 598. Unfortunately it would make the cable even more snag-prone, and only serves as a roundabout solution. OK, enough handshakes and empiricals, let’s get to the headphone behavior itself!
 
THE MUSIC EXPERIENCE
In Full Disclosure: Before I go further with this section, I do need to disclose that my music experience is based on using my HD700s in stock configuration through a PONO player. The PONO Player is a DAP that was designed by Ayre Acoustics, and much of it resembles a sort of cross-breeding between a traditional DAP (ie: iPod) and the Ayre Codex, which is a dedicated DAC / AMP that shares much of the PONO’s design, albeit in a larger and SUBSTANTIALLY more powerful form factor. The PONO has a balanced mode achieved with certain headphone / cable combinations that does allow for the player to send double the power up to the headphones, while effectively canceling out noise, but for the purpose of this review, I will limit my observations to single-ended (ie: plugging one 3.5mm jack into the player) experiences, with the volume at approximately 35 to 50% for the HD700s.
 
The initial impression of these headphones was, to put it gently, BOXY. Sure, alcantara feels nice, the body and cable and connection reek of quality, but these headphones were BOXY… the soundspace was not developed, bass was dominant, with mids and highs nowhere to be found. I decided to give the headphone a bit of “break-in time” where I wouldn’t listen, and I would return to the same track in a week to see if any progress ensued. I performed about 20 to 25 hours of break-in by leaving the PONO player charged and leaving the PONO in “mix mode” so that it could randomly pick tunes while I was at work to feed the HD700s in the hopes of “opening them up.” The test song in this case was “Good Lava” by Esperanza Spalding off of her 2016 Album “Emily’s D+Evolution.” I bought the album in 96/24 WAV from HDTracks. The listening level on the PONO was approximately 35 to 40%, accounting for the lowish DR of the song. The initial listen was all bass, and there was not a great amount of fidelity in Ms. Spalding’s voice, and the soundstage was a bit more closed in than I would have expected. I knew these were 150 ohm headphones, so they may have been a bit hard to drive. So I looked at InnerFidelity’s headphone measurement compendium for the HD700’s page (see: http://www.innerfidelity.com/images/SennheiserHD700.pdf) and found that only 0.15 volts was needed to get to a 90db listening level. A bit higher than ideal for running single-ended (it should be less than .1v RMS), but not as bad as I feared.
 
After the initial break-in with the aforementioned track, I found that Ms. Spalding’s voice opened up, there were more than just pile-driving bass and drums to be found, and that the various instruments (guitar, bass, drums, backing vocals) had begun to space themselves out to where the songs did not sound as “congested” as initially. I tried a different song, “Kodachrome / Maybelline” off of Simon and Garfunkel – The Concert in Central Park, in order to move away from the bass-heavy to something a bit more folk-rock in nature. (Format: 192/24 WAV, also from HDTracks.). Whereas the HD700s absolutely crushed it with the bass-heavy fusion-cum-funk-cum-jazz of Esperanza Spalding, they presented almost an excessively heavy-handed presentation to Kodachrome that gave a wide soundspace, but over-emphasis to the bass and drums. Other songs, such as “Mrs. Robinson” and “The Sound of Silence” had an exquisitely open, yet never brittle, presentation. In comparison, the HD598s, even with the improved Blue Dragon cable, gave a very bass-light presentation to “Good Lava,” but absolutely nailed it with Simon & Garfunkel. These HD700s weren’t your traditional Sennheisers, they were bringing me back to my days as a college DJ where I ran my show with Grado RS2s into a console…. Punchy, and in your face.
 
I decided to mix things up a bit and move away from folk-rock and modern-engineered fusion-pop and geared up to my reference albums; Bob Marley: Legend (192/24 WAV), Miles Davis’ Kind of Blue (192/24 WAV), and Claudio Abbado conducting the Berlin Philharmoniker through Beethoven’s 9^th symphony (96/24 WAV). Each one gave me a varied result. Bob Marley’s Legend was a bass-heavy experience on the HD700s. I never felt wanting for more bass, and the album hit the headphones hard. At this point, I realized that the HD700s were something that the 598s were not: FAST. These headphones never stumbled over passages that melded piledriving bass lines with delicate female background vocals, nor did they fail to pick up nuances when instruments peeked in (i.e.: Jammin’) out of nowhere. This trend of picking up nuances continued with Kind of Blue. On the HD598s, the opening of “So What” had a noticeable bassline, but the HD700s revealed a more analytical mindset, picking up the bass plucks, but the sound of fingers going onto the fingerboard right before the pluck itself. My fears that the lack of treble would hurt the listening experience (as it did somewhat in the Simon and Garfunkel Central Park concert) were unfounded, as even Bill Evans’ delicate piano work was brought to the forefront. Even in “All Blues” where the piano takes a backseat to Miles’ muted trumpet, the random progression of piano that sounded like one note being pushed constantly was in actuality many notes played rapidly in a progression. The HD598s stumbled here, seemingly having to choose between muted trumpet and rapid piano, and not asserting either one.
 
Lastly, Abbado’s rendering of the 9^th symphony. I’m not going to ever say that the HD700s are the ideal “classical listening headphone,” as while they are analytical, they’re anything but reference (whereas the HD598s are not terribly analytical, but very neutral). They powerhouse through the album, and while they sacrifice some absolute top-end, they bring out the bass. On O Freunde nicht dise Tone”, the bass of the timpanis was highly emphasized, while vocals and violins somewhat subdued, although very existent. I’m not sure if this is because the DR of this album is 16, or if it’s because the glut of this album is outside of the HD700’s sweet spot. I consistently found myself having to raise the volume, only to be caught out by one of the more powerful sections (i.e.: Ode to Joy) of the movement. At the same time, it could be that the PONO is near its power limits in single-ended operation. The HD598s won out here, being grainier in delivery, but more consistent based on the available amount of power that could be sent to the headphones.
Listening to the HD700s is not like any other Sennheiser, and could be described as a cross between the analytical nature of the HD800s, and the in-yer-face nature of a Grado RS2e. It does reveal flaws and limitations in the playback media, the DAP, as well as even in the listener. At 150 ohms, it is right at the limit of what the PONO can do single-ended without any outside help. That being said, they have become my #1 go-to headphone for music listening, and won out over the HD800 and HD800s when I went to buy them.
 
SO WHERE FROM HERE?! (AND WHY OVER THE HD800?!)
I will wrap up this review by answering the second question first. To be blunt, the HD800 is a WONDERFUL headphone, analytical, and more than capable of bringing out the best of your DAP and DAC / AMP setups when configured right. However, with Rock Music, or any DAC / AMP combo, it becomes the headphone equivalent of Sheldon Cooper from the Big Bang Theory. Wickedly intelligent, yet incapable of not talking about quantum physics even at a beer bash. It is so open and revealing the sound almost appears distended. The HD700s, on the other hand, proved to be adept at classical music, providing enough soundspace to be enjoyable, yet not sounding distended when listening to rock and roll. It showed the limitations of low DR / poorly mastered albums, and still allowed the reference works plenty of space to show off why they are considered reference material.
 
The first question is not as easy to answer. The PONO is amazing with the HD700, but I feel is pushed to its limits powerwise. Additionally, in the brief attempts with my computer, the HD700s never felt fully powered. I may take two steps to rectify this: A balanced cable for the PONO to allow for more power to hit the HD700s (and possibly opening the sound up even more and getting rid of some fidelity issues), and getting a dac / amp setup to plug into my computer to allow for even more power than the PONO could ever provide to get to the HD700s. Whether I go with a combo such as the Ayre CODEX, or some sort of dac / amp combo remains to be seen, but the HD700 is a great headphone, isn’t terribly picky, but just needs some extra power to really make it shine.
 
9/10.
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
INTRO
After months of letting my obsessive compulsive disorder (OCD) get the best of me with how to address the two major issues befalling the HD5x8 series (and much back and forth with Drew at Moon Audio), On October 19, 2015, I ordered a 5 foot Blue Dragon ($165 USD) with a 1/8” Oyaide gold-plated connector ($5 USD upgrade charge) for my HD598s (Total cable cost: $170 USD). On October 26, 2015, I received a double-wrapped envelope from Moon-Audio with my HD598-compatible upgrade cable. From start to finish, the support was impeccable, but let me go into why I ordered this cable and what it has done from the get-go.
 
THE HD598s (Independent of the Moon Audio Cable)
The Sennheiser HD5x8 series are in a bit of a bind as to what they want to be. On the one hand, they resemble slightly less robust HD6x0 series headphones that would not look out of place in a studio as basic monitoring headphones. On the other hand – per the side of the box that my HD598s came in – they're suitable for use on Apple and Android portable devices such as iPods, smartphones, and iPhones. This is due to a lower 50 ohm impedance versus the 300 ohm impedance on the HD600 / HD650 headphones. There are two major problems with the HD5x8's cables that keep it from being a viably portable headphone. First, the headphones come with a 10 foot long cable, which makes portable listening difficult. Second, the headphones terminate in a 1/4” connector, and while Sennheiser includes a 1/4” to 1/8” converter jack, the use of this converter on laptops, iPods, and smartphones can cause excessive torque on the connectors, while the long length of the factory cable makes it susceptible to being tripped on and the converted jack becoming a lever to rip connectors off of the boards they're soldered on (this happened to me twice, prompting me to get a shorter and less torquey cable).
Thankfully, the HD5x8 series (and higher) have removable cables to address this issue. Additionally, the HD598 is a very neutral headphone to the point that it can be considered “bass-light.” In the $150 to $250 market it competes in, where the main player is Beats, SOL, and other “bassy” headphones, this separation by tonality puts it more in the market with somewhat more pricey AKG's and Audio-Technicas. Thus, the distance in bass between the HD598s and headphones in this price range commonly worn by college-age students means that, at least in theory, enough room between the HD598s being tested and a pair of beats exists in the “Bass Department” that if the Moon Audio Blue Dragon brings out more bass, that the clarity and overall neutrality of the 598s will be preserved.
 
The Cable Itself (Outside of Sound)
Blue… Sonic the Hedgehog Blue… which goes about as well with beige and brown as the vest and jacket from a 3-piece suit would go with a pair of torn blue jeans. Thankfully, the outside color doesn't determine the sound, but rather the internals and build quality do. Comparing the Blue Dragon to the stock HD598 cable is like comparing a McDonald's burger to a fresh burger made at the local chophouse in look, feel, and quality. It's the first step in possibly figuring out why the HD598s are so lacking in bass. OK, so look and feel may not have a great deal to do with the bass issue, but they provide clues to the craftsmanship that a company provides. The blue dragon has a sleek appearance, with no bumps visible on the surface nor the shrink-wrapping at either end. Judging by the cut on the shrink-wrapping, I'm led to believe that the cables are largely handmade rather than made by a machine, and it shows in contrast to the HD598's stock cable, which was loaded with kinks, rough rubber jacketing, and that springy stress-tensioner that only gets more leverage with the converter jack on it. Additionally, the Blue Dragon is not a super flexible cable, which can be a benefit and an issue.
The 24AWG copper conductors in the Blue Dragon, along with the various shielding and jacketing properties, contrast to (I'm going to guess 40AWG at the largest with little to no shielding) the stock Sennheiser cable by having both a particular “wrap pattern” as well as quite a bit of rigidity. Whereas the stock cable basically flops on itself with or without the converter added to it if anywhere more than a 6 inch portion is held as an overhang, the Blue Dragon rises, apexes, and droops a tad. This cable is stiff, directional (it doesn't like to be wrapped against the grain, and I don't think it should be), and reeks of quality. The downside to this thickness and rigidity is that a) the cable cannot simply be “stashed” in a case because of its directional loop; and b) I find that the cable behaves best when the cable is allowed to flop naturally, then lined up with the HD598's earcup, then screwed in, rather than trying to be screwed in with the headphones upon one's head. So what we have is a phenomenally built, gorgeous looking, sensory-pleasing cable for $170… What good is that, if it provides nothing more than a shorter and more compatible cable for the HD598? Not… Much. Thankfully, early listening proves otherwise.
 
Burning in a Fire-Breathing Dragon for Ten Hours
Before I go further into my review with regards to sound, I'm going to outline my listening methodologies for replicability's sake. It's a portable setup that goes with me to work. Here goes.

1. Player: Pono Player (Clear Kickstarter Edition)
2. Music Files: 96/24 WAV or 192/24 WAV bought from HDTracks.com
3. Headphones: Sennheiser HD598s
4. Cables Compared: Stock HD598 Cable vs. Blue Dragon HD598 Cable.

Figuring “how much of a gain in sound could I get?” I set the volume on my Pono to 50% - my personal default level. Bad… bad… idea. The larger conductors and shorter cable length apparently acted like a “volume booster” for every single song I had on my Pono. 50% (which was usually comfortable) now hurt my ears and required a volume reduction back down to 35 to 40% volume. I emailed Drew at Moon-Audio, and wondered if this was merely an increase in bass compared to the stock cable, or if there was something else happening. Drew responded that because the Blue Dragons have a lower resistance (larger copper wire + shorter distance = less resistance), that there would be higher gain. With this info in tow, and newfound lower volume (so as not to go deaf at 30 years of age), I began testing.
The first song I tested was “Paranoid” by Black Sabbath (96/24 WAV). The reason for choosing this song was because with the stock cable, the bass line is thin to the point of being nearly non-existent. The Blue Dragon not only brought back the bass-line, but also made it easier for me to discern between the bass drum and the bass when the two played together. Unexpectedly, however, Paranoid's fuzz guitar solo cleanly split across the two channels. The left channel (where the headphone cable enters the headphone) delivered the “clean” track, whereas the right channel solely delivered the fuzz track. In contrast, the stock cable seemed to mush everything together, there was a bit of fuzz leakage into the left track, which concealed the overdub in Paranoid that the Dragons exposed. Some may say this “airy” behavior may detract from the loud and compressed nature of early metal, but part of music is to discover new things, and I'm all for that.
Heading a bit more in a prog-rock direction, the second song I tested was “Kashmir” by Led Zeppelin (96/24 WAV). Why “Kashmir?” First, it's one of the most famous songs of the 20^th century; Second, almost everyone at least knows the rhythm to Kashmir; and Third, it has many layers of synth, strings, electric instruments, and apparently vocal overdubs. Two things I noticed with the Blue Dragons that were not noticed with the stock cable were a very subtle bass line that melded with the bass drum beat (sometimes it was off by a little, which revealed it), and in the first verse of Kashmir (starting with “Oh let the sun beat down upon my face...”) there is a very faint do-do-do-do-do-do-do-doooooo (the keyboard bit that becomes more prominent in the second verse) that can be heard in the first verse, as though John Paul Jones is prepping his synth playing. Again, bass explosiveness is increased, although it does not “compress” the music in the same way as a Beats or SOL republic headphone would. For rock music, this is a great cable.
Moving to Jazz, Fusion, and R&B, there is a bit less consistency in the improvement of sound. For Fusion, I listened to “Chameleon” off of Herbie Hancock's Headhunters (96/24 WAV). This is a bass-heavy song, and the Blue Dragon absolutely ate it up. Splat-tones in the opening became much more revealed, the bass had a newfound intensity that made me blink each time I heard it, and even the higher keyboard notes were no longer tinny. Additionally, the headphone felt faster, as while the fadeout of notes was more linear, the impact was more dramatic. Note, the HD598 is NOT a fast headphone, so it can sometimes flub bass-heavy lines or lose them altogether. This was a welcome improvement, and improves listenability. I'm going to do more testing on other fusion albums such as Bitches Brew, but for a first impression in fusion, wonderful job.
In R&B, my test sample was “Inner City Blues (Make Me Wanna Holler)” (192 / 24 WAV) by Marvin Gaye. Here we run into a slight problem. The song has a lot of highs, a lot of bass, and not very much in the middle (besides Mr. Gaye's voice). The opening bass line is complemented by the “ding” of a Triangle. Although the bass is far more focused and impactful, it comes at a slight cost to the clarity of the triangle “ding.” (Ironically, this issue was felt with the outro of “Children of the Grave” by Black Sabbath, where the blue dragon's bassiness made it a little more difficult to hear a faint hurdy-gurdy in the background.) Overall though, a very impactful listen, and truly enjoyable.
Lastly, “So What” (Stereo) (192/24 WAV) by Miles Davis. Already an EXCELLENT remaster for HDTracks (there's a video with HDTracks' backstory on this remaster), the Blue Dragon did not do very much for this album. I'm not putting any blame on the dragons, the player, nor the headphones because even with the stock cable Kind of Blue (the album “So What” is on) was fantastically remastered. When you get to more traditional jazz (or classical), I'm going to echo Drew @ Moon-Audio's sentiment to get the Silver Dragon. Although the Silver Dragon for an HD598 is cost-ineffective (the headphones are $150 to $250; the Silver Dragon is $275 minimum) to the point I'd almost be inclined to say save up for an HD600 and get balanced cables for the PONO to better serve its 300 ohm impedance.
 
Final Thoughts
If you're looking to buy this cable with the intention of turning your HD598s into “Stealth Beats,” just go buy a pair of Beats; these aren't the headphone for you. If you're looking to expand the clarity of traditional jazz and your source media and player are good, stick with the stock cable or skip the 598s and save up for HD 600s and possibly a cable upgrade. If your music tastes run from jazz, to rock, to early metal, you have quality media, and a quality media player that has only a single-ended output (Spotify at 128kbps doesn't count here… although Tidal @ 16/44.1 or Qobuz @ 24/96 will), then I absolutely recommend the Blue Dragon upgrade for the HD598. More volume at equivalent levels, a tighter and more present bass, and 99.9% of the neutrality of the stock setup, but does not tangle or have kinks like the stock cable. Now, the Pono player has balanced output capabilities… so about that HD650 / Blue Dragon kit with some nice balanced connectors for PONO… so, so very tempting after just how much improvement the Blue Dragon did to the 598s.