PRO750 flat 4cULTRASONE PRO 750

Like any respectable headphone manufacturer, Ultrasone claim to have unique technologies that make their headphones superior to their competitors. In their case, that feature is labeled ‘S‑Logic’, which is supposed to make the experience of listening on phones more like listening on loudspeakers. This isn’t a form of digital processing, but refers to the physical geometry of the phones themselves.

If you’re used to typical studio phones, the first thing you notice when you put on the Pro 750s is that the ring‑shaped cushions around the edge are much deeper than usual. They still form a seal around the ear, but position the actual drivers quite a bit further from your head than do standard phones. The ear cups themselves incorporate complex baffles which, according to Ultrasone, “decentralize the sound”. So instead of the drivers firing directly into your inner ear, the sounds are reflected into the inner ear from the outer, in an effort to mimic the way sound arrives from loudspeakers. Ultrasone describe S‑Logic as generating “natural surround sound”, and also claim a side benefit of reducing the risk of hearing damage. All in all it’s quite a marketing story; forgive me, but all that’s missing is a collie and a little girl stuck in a well.

That aside, the design of the Pro 750s sticks pretty closely to what most of us consider as good headphone design. The cable is detachable, and screws into the base of the left earpiece. Two cables are included: an annoyingly short, straight one with a mini‑jack, and a longer curly one with a full‑sized connector. A nice touch is that the Pro 750s ship in a padded case with a spare pair of ear cushions. The phones themselves are made out of reasonably heavy‑duty plastic, are easy to adjust to fit your dome, and weigh in at about 10.4 ounces. They’re also reasonably comfortable in use, although because the drivers sit so far from your head, there’s less isolation from external sounds than with most closed‑back phones. The specs list their impedance as 40 ohms, and although they are a fair bit less sensitive than my usual AKGs, any headphone amp worth its salt will have no trouble driving them.

The Pro 750s present a frequency balance that is very bright, with a response of 8Hz to 35kHz and a sizable bump in the upper mids, though some initial harshness was tamed once the headphones had been burned in for a while. The bass end of things is strong, with somewhat of a dip in the lower mid‑range. Their brightness makes the Pro 750s highlight transient detail, but also they also tend to exaggerate sibilance. In this case my concern was how the brightness of the high end would translate, and whether extra care would be needed to tame sibilance.

Still, I did not become fatigued when working with the Pro 750s. This may be a side benefit of the S‑Logic technology or it may not, and I still find the whole S-Logic straining credibility, but S‑Logic does make a difference to the experience of listening on headphones. It’s often very subtle, but I did sense a sense of spatial separation between individual sources that doesn’t normally exist with conventional closed‑back designs. In no way did I believe I was listening to loudspeakers, but I did feel the center-panned sounds were coming from in front of me rather than from inside the middle of my head (which is somewhat vacant anyway, right?). It’s not a dramatic effect, but there is something different there. If you spend a lot of time listening to and creating production material on headphones, these bear an audition.

The Ultrasone PRO 750 Professional Headphones carry a US retail price of $409, with street prices in the mid-$200 range. For more information, visit


I’m still not quite ready to pull the trigger on a new pair of cans, although I definitely enjoyed the experience. I may try yet again to repair a pair I have, or Frankenstein together one good pair from carcasses; they just don’t make ‘em like they used to. I am tempted by the beyerdynamic cans, provided I can deal with the fitment, but it looks like it’s back to the Famous Music Store with these. Perhaps I’ll bring home another batch.