Ultrasone is a German firm that makes headphones for DJ, hi-fi, and professional applications, though it is perhaps best known in the United States for its pro-series models. I debated whether to sample one of the hi-fi- or proseries models for this survey, but ultimately settled on the firm’s flagship professional phones: the PRO 2500s. I was influenced, admittedly, by the follow teaser descriptive found on the Ultrasone Web site: “You prefer open-back headphones? … the PRO 2500 model provides due to its open-back design the most airy sound within the complete PRO line. Accuracy and the finest sound reproduction is guaranteed. …”
The Ultrasone PRO 2500 produced what I think many listeners would consider a “big” sound, and the exhibited considerable sonic potential—albeit potential I felt was not fully realized. The PRO 2500 offers excellent bass—some of the deepest and most powerful bass I’ve heard from any headphone— and lively upper midrange response that is generally clear, but that sometimes sounds excessively “splashy” on hard transients. The weakness of the design, however, is that its overall tonal balance is considerably more uneven than that of many other ‘phones in this price range. As a result, bass and upper mids sound overly prominent, while lower mids and extreme highs tend to sound somewhat recessed.
“Take Me To The River” from Eva Cassady’s Live At Blues Alley [Blix Street Records] shows both the strengths and weaknesses of the PRO 2500. The song opens with a spectacular, plunging electric bass glissando, which the Ultrasones reproduced with real gusto (when you hear that bass fire up, you’ll want to jump out of your seat and boogie). And when Cassady belts out the familiar opening line of the song—“I don’t why/I love you like I do”—the upper register of her voice falls within the PRO 2500’s upper midrange emphasis region, so that her vocals at first sound powerful and dramatic.
But as the song unfolds and Cassady starts to draw upon the lower register of her voice, problems cropped up. The PRO 2500s made the lower register of Cassady’s voice sound somewhat subdued and withdrawn, which is really not how the record should sound. At the same time, the Ultrasone’s made the ride cymbal pings that pace the song’s chorus seem overly brash and splashy, while paradoxically rolling off the cymbals’ delicate, silvery, high-frequency overtones—again, not the way this record should sound.
My conclusion is that the Ultrasones’s very real sonic strengths are undermined by the unevenness of their tonal balance, which makes listening to the ’phones a bit of an unpredictable sonic “roller coaster” ride.
The PRO 2500s offer very comfy earpads, but nevertheless fell about mid-pack in terms of comfort for two reasons. First, the ’phones feel heavier than their specifications would suggest and carry a good bit of their weight up high—in the headband. Second, the headband is not padded across its full width, but only in a 3–4-inch wide strip in the middle, which concentrates pressure on the top of your head.
The bass and, to a degree, the upper mids of the Ultrasone PRO 2500 show great promise, but uneven tonal balance keeps these ‘phones from realizing their full potential. Even so, the PRO 2500s manage to produce a big, bold sound. We applaud Ultrasone’s pioneering efforts to reduce electromagnetic radiation and to minimize the need for excessive volume levels—both steps taken in the interest of consumer safety.