PAR Session Trial: Premium Studio Headphones

Featuring AKG, Audio-Technica, Shure, Sony, and Ultrasone
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Vocalist Deirdre Kroener with her top pick, the AKG K702.

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In the interest of full disclosure, I don’t like using headphones. They often fall off at just the wrong moment, squeeze my earlobes, and/or fatigue my eardrums. Their frequency response is typically too uneven for trustworthiness in mixing, nor voiced right for pleasurable, long-term monitoring when tracking.

That said, our industry’s top headphone manufacturers have recently unveiled some ambitious new models flagged specifically for studio use, promising improved sonic performance and better fit as many more audio engineers are monitoring, editing, and mixing in compromised environments or “on the go.” Especially within the new breed of young engineers, many headphone mixes are done simply to avoid the faulty sonics of their working environments (converted bedrooms, for example). Thus, the time is right for a thorough evaluation and possibly some serious reconsideration on my part.

This, our eighth Session Trial — PAR’s ongoing series of comparative, real-world gear evaluations — examines the following premium studio headphones: the open-back AKG K702 ($539 list); the closed-back, collapsible Audio-Technica ATHM50 ($199 list); the closed-back Shure SRH840 ($250 list); the closed-back, collapsible Sony MDR-7509HD ($265 list); and finally, the closed-back Ultrasone HFI-680 ($249 list). All are well-built, full-size, ear-surrounding models and are most definitely “professional grade” headphones.

Tracking Session

With a modern rock trio in for a tracking session, I had ample opportunity to see how universally the cans fit, if they caused any premature fatigue, and if they gave the performers what they needed to hear.

As the musicians warmed up, I had them each try out a pair of phones, record for a spell to get over any initial shock, and then gauge each model’s comfort and overall desirability. Right off the bat, our participating contenders showed that great strides have been made in the realm of comfort (unfortunately, we didn’t have the Ultrasone HFI-680 for this session). All four sets not only fit comfortably, they mostly stayed on even if the musicians leaned forward (an important, if dull improvement). Atypically, everybody stayed in their cans the whole session without switching to listen back to monitors — a testament to the long-term comfort these newer designs provide.

As it turned out, the Achilles heel of our testing plan was that I needed more pairs of each headphone, as both our drummer and bassist really wanted to use the Audio-Technica ATH-M50. In my opinion, the M50 proved to be the best tracking cans for one dominant reason: They actually deliver as much bass as these performing musicians wanted to hear. So many modern musicians are used to kick-drum-heavy productions that it’s only natural that they want to hear this fundamental timekeeper rather loudly; the ATH-M50 was the only headphone with extended low bass, sufficient mid-bass (for easier bass guitar audibility), and a lack of a singular “bass bump” that “fakes” bass, even if the overall content is rather low. Our drummer settled on my studio’s Sennheiser HD280 headphone (offering high output, but a comparatively “peaky” bass response) as the bassist was using the ATH-M50; our drummer needed lots of kick drum/bass guitar that the other phones could not provide.

This guitarist is one of those fellows who doesn’t love so much chesty 80 Hz as he does some “in your face” 2-4 kHz. He gravitated to the Sony MDR-7509. They fit him perfectly, produced a tight and punchy bottom that he likes which accentuated his instrument, even as he shared a cue mix with the bassist; there were no “more me” squabbles since both cans delivered to each performer his preferred frequency range.

The Shure SRH840 nearly secured the top pick from all parties involved, and were only comparatively lacking in bottomend output. The open-back design of the AKG K702 was just wrong for this loud trio’s session (especially since we didn’t want any click-track leakage), but I maintain that such open designs are ideal for hearing some of the room and getting a “mostly me” mix in the cans that works well for larger group sessions in bigger rooms (especially group vocals).

Overdub Sessions

Before using any of them with musicians, I first tried out all our phones on a grab bag of overdub monitoring: everything from electric guitars, bass guitar, lead vocals, backing vocals, and VOs. I used the Aphex Headpod 454 for amplification; it employs four clean headphone amps, which allowed easier volume matching, plenty of headroom, and eliminated any possibility of loading issues. As a result, I discovered a favorite for each individual application.

My overall favorite was the Shure SRH840 for having a good top to bottom balance, minimally fatiguing harshness up top, a comfy fit, and a comparatively neutral voicing that worked well with almost all overdub sources. Close behind were the Sony MDR-7509HD and the Ultrasone HFI-680; both delivered with a lean bottom that didn’t overwhelm and good vocal intelligibility, hindered only by some high-end hype (maybe 10 to 12 kHz) on the HFI-680 and some uneven mids in the MDR-7509HD.

These overdub session tests revealed just how high impedance the HFI-680 and AKG K702 are (at 75 and 62 ohms, respectively), requiring a good 50 percent more power to get up to the same output level. When the levels were matched, the K702 became my favorite for vocals by a wide margin. They may seem a little thin by comparison, but with such open-back designs, one doesn’t feel the urge to “half cup” one ear when seeking vocal blends and harmonies; you can actually hear yourself and the room lightly blended in.

Monitoring VOs, the HFI-680 and Shure SRH840 were my favorites for a more compressed sound that allows for better tailoring of the bottom-end bombast with proximity. On VO as well as instruments, the full bottom end of the Audio-Technica ATH-M50 was a bit too much; it seemed to reduce vocal clarity, getting a little clouded at times and even a tad lacking in dynamics overall.

Vocal Session

Vocalist Deirdre Kroener laid down some vocals using our five phones and shared some insight on her preferences. After run-throughs with all five, she commented that all sounded accurate and she’d be ��tickled to have any of them.” For her, it seemed that the main issues were comfort and the avoidance of undue pressure on her ears, the latter of which can cause a bassy and muffled sound, forcing her to hear too much of her head’s internal vibration and not enough of what the microphone itself had captured.

Deirdre’s favorite was the AKG K702 by a long shot. She praised it for “capturing the mic” and said it “sounds just like playback” without any pitch surprises from too much head voice — a testament to the oversized speaker cups and open back design. She also liked the Sony MDR-7509HD for excellent comfort and “good clarity.” She found the Shure SRH840 a touch uncomfortable and bassy, the Audio-Technica ATH-M50 being far too thick-sounding and snugfitting, accentuating head voice. Deirdre clearly preferred the models with a straight cord instead of a coiled cord (I’m neutral on the issue).

Mix Tests

I found myself working on an uptempo pop/rock mix that was difficult to balance out, struggling to get the fundamental elements like kick drum, snare drum, triggered samples of both and the vocal to sit just right, when I realized this was a perfect time to really “learn” these headphones.

Today’s pop mixes require lots of bottom end, and none of the tested units deliver as much bottom as the Blue Sky SAT8 (with SUB212) monitoring system I was concurrently reviewing or my own JBL 4328 (with LSR4312 sub) monitoring system. As I slowly got my kick drum/kick trigger/bass guitar thing happening (after additional checks in my car and on my desktop system, too) and I confirmed that all the headphones except the Audio-Technica ATH-M50 provided inadequate bass content for my mixing needs, yet some had much greater accuracy frequency-wise (like the Shure SRH840), while others (like the AKG K702 and the Ultrasone HFI- 680) seem to “get” the damping (the looseness vs. punch element) more accurately.

A little bass tilt can be worked around, but each set of phones had not only its own points of “frequency overemphasis,” but a distinct frequency where most of the distortion began to become apparent at higher volumes. Working at a reasonable level (that felt like it was about 85 to 88 dB on monitors) that minimized distortion, I still found all the headphones unusable for detailed mix decisions because I just simply could not trust the midrange content. It seems that the inaccuracies are often in narrow frequency ranges, with spots of emphasis and attenuation often at adjacent frequencies, making some response curves feel almost comb-filtered in their midrange nonlinearity. I tried making such midheavy decisions — like guitar EQ, snare EQ/placement and vocal placement — only to find that I had degraded an otherwise good mix with largely inappropriate decisions (although some were quirky and interesting — not exactly my ideal).

Nonetheless, I found the imaging and soundstage of the AKG K702 and Sony MDR-7509HD to be the most lifelike and believable, with transient reproduction particularly good on the AKG K702. Both the Audio-Technica ATH-M50 and Ultrasone HFI-680 sounded slightly compressed in their dynamics, a nonlinearity that may be not be so bad for tracking.

Once I (finally) had a good mix, I could see how, after interpreting their bass tilt and nonlinearities, I could easily put all five headphones to regular mix use in my studio. I often check my mixes on three other headphone models: AKG K240, Grado SR125, and Fostex T50RP. The key word here is “check” — at that point, such mixes are nearly finished and I’m just looking for certain elements to balance. Many mixers use Auratone-style monitors similarly and each of us has our own imperfect, yet important, reference system(s). (Who doesn’t check mixes in their car?) For such important “translation checks,” I could learn to be comfortable with any of the headphones tested here.

Summary

On the Ultrasone Edition 8

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For this PAR Session Trial, Ultrasone submitted two headphone models for consideration: the aforementioned HFI-680, which we included, as well as the Ultrasone Edition 8 ($1,499 street). Among other creature comforts, the posh Edition 8 features such unique materials as Ruthenium outer ear cups and Ethiopian sheepskin leather — materials that Rob considered cosmetically and aesthetically impressive, yet ultimately cost-prohibitive for most studio needs. However, it was their decidedly “audiophile” performance that led to their exclusion from the Session Trial evaluations.

“Out of the box, I found them to be consumer-oriented,” explains Rob. “For example, they have a very short cable, one that professionals could not use in the studio. While their fit was killer — I almost considered them for the fit alone — the frequency response was way too sculpted and nowhere near flat. The Edition 8 has a frequency-response curve that is sculpted in a way that only consumer headphones would be; the response, while exciting, is unusable for studio use, especially for mixing.” — Ed.

The Audio-Technica ATH-M50 gets my top rating here for easily the best bass response of the group (almost as good as nice monitors); very little distortion (maybe some way up high at 10 to 12 kHz); only moderate mid-combing; and a slightly understated top end that is unobtrusive for long tracking sessions. Although ideal for tracking, they’re still not flat enough for efficient mixing and are a little bassy for many overdub purposes.

I’m hard pressed to pick a second favorite, but the AKG K702 slightly edges out the Shure SRH840 and Ultrasone HFI-680. I personally like the open-back design of the K702, its accurate mid-midrange (best of the five), fantastic imaging (best of the five), and natural-sounding bottom end. If only they had more of this bottom end, more low-mids at 125 to 200 Hz, and less distortion at 3–4 kHz, it could be my top pick.

Conversely, the SRH840 and HFI-680 have pretty darn good bass response, only moderate inaccuracy in their mids, and an excellent lack of leakage. I wish the SRH840 was a little more animated in the top end, and I wish the HFI-680 had more midbass content (and less distortion way up high); yet both are more than adequate and way better than my critical observations may imply. I did get an excellent fit from the SRH840 but not the HFI-680, although that may be personal.

I had mixed reactions to the Sony MDR-7509HD, although I thought the fit was the best (no ear or crown pressure, whatsoever), and my clients chose them based on their sound twice, so we obviously disagreed. There seems to be little below 80 Hz and the midrange is seemingly bumpy, with many peaks and dips. They also seem to “ring” at 6 kHz and distort at about 10 kHz, but (to be fair) many users love this sculpted frequency curve more than I do. These characteristics have made the Sony MDR-7506 (predecessor to the MDR-7509HD) almost an industry- standard headphone. Those who love the 7506 will appreciate the 7509’s similar curve, but with deeper bass, less top-end shrillness, and a bigger soundstage.

There is another critical factor of headphone evaluation that was omitted from this Session Trial — durability. Selecting headphones for performers is often more skewed towards models that take abuse, or at least are easily repairable. I have a halfdozen Foster T20RP headphones for their durability and reparability, but only time will tell if our Session Trial contenders hold up to the banging around, sweat, and high SPL of typical rock ’n’ roll tracking sessions.

I’ll go on the record here: Headphones are still not a viable replacement for mixing on either nearfield or midfield monitors. I know many of you find balances on phones as part of a successful production routine (and I won’t doubt that many mix better on cans than I ever will on the finest monitors). That may evade the point, however, since speed, efficiency, and a lack of “educated guesswork” may be equally important factors to consider. Modern headphones are, by necessity, a workable alternative to finely tuned control rooms; thus, these personal monitoring environments are sure to become even a bigger part of our fast-changing audio landscape.

Rob Tavaglione owns and operates Catalyst Recording in Charlotte NC. Please contact him atrob@catalystrecording.comfor questions or comments.