Headphone Reviews

It's not so easy to convert a headphone to Bluetooth. You've got to find space for the amplifier, processing circuitry, radio transceiver, and battery-and all that stuff taking up space inside the earpieces can change the sound a lot. Plus you kinda have to have a cabled mode, because you can't use Bluetooth on airplanes. And you probably want the cabled mode to work even when the battery runs down, and to sound more or less the same as Bluetooth mode, too. It's a much tougher task than simply designing a set of passive headphones.

A glance at the spec sheet suggests Klipsch has handled the task well with the Image One Bluetooth. It looks much the same as the Image One, but with a bunch of controls on the right earpiece. There's play/pause, forward and reverse track skip, power/mating and volume up/down. Unlike some Bluetooth headphones we've tried, the operation of the controls is totally intuitive, and it's easy to manipulate them by feel.

You probably couldn't expect more comfort from a set of on-ear headphones. I found I could easily wear the Image One Bluetooth for an hour and almost forget it was on. The fit wasn't tight enough for jogging, but it was perfect for dog-walking. I was also happy to see that the Image One Bluetooth has a standard micro USB jack for charging.

Frequent West Coast headphone tester Will Huff agreed; he hates the way most on-ears feel but was completely happy with the way the Image One Bluetooth coddled his earlobes. He also loved the design, especially the V-shaped button on the right earpiece that controls power and Bluetooth mating.

So … looks, check. Styling, check. Ergonomics, check. Now let's give a listen….

Bass in your face

To me, the Image One Bluetooth looks like it was designed for the 30+ set. It has an elegant-yet-techy look somewhat reminiscent of the Bose QC-15 and commonly seen on many other biztraveler-type 'phones. That's why I was so surprised to hear how bassy this headphone sounds.

In the mood for a '70s binge during a recent dog walk, I cued up Yessongs on my Samsung Galaxy S III. You know the sound of classic Yes: Chris Squire's trebly Rickenbacher 4001 bass and Bill Bruford's intricate jazzy drumwork underlying dense layers of vocal harmony, guitar, and keyboards. Well, the sound of "Yours is No Disgrace" was totally dominated by the bass, although it sounded more like Fender Precision than a Rick. The vocals, in particular, were buried, almost as if I were listening to a 5.1 music mix with the center speaker disconnected.

Same held for "Trilogy" from the Mahavishnu Orchestra's The Lost Trident Sessions. Bassist Rick Laird was something of a bit player in this band, holding down the bottom while guitarist John McLaughlin, violinist Jerry Goodman, and keyboardist Jan Hammer did what amounts to a triple-tempo modal jazz take on "Dueling Banjos." Through the Image One Bluetooth, Laird became the band's most prominent player, and I heard not the articulation of his notes (he was a exceptionally clear and precise bassist for his time), but only the boom.

Although I didn't share my opinion of the Image One Bluetooth with Will, he said almost exactly the same things. "There's no high frequencies," he said, "and the mids are mostly obscured. It's all bass." When I asked him to comment on the sound of the headphone in Bluetooth versus wired mode, he said, "I can't. I didn't hear a difference, but I couldn't hear much of the midrange and treble in the first place, so I'm not sure I'd be able to tell, anyway."

Measurements

I measured the performance of the Image One Bluetooth using a G.R.A.S. 43AG ear/cheek simulator, a Clio FW audio analyzer, a laptop computer running TrueRTA software with an M-Audio MobilePre USB audio interface, and a Musical Fidelity V-Can headphone amplifier. Measurements were calibrated for ear reference point (ERP), roughly the point in space where your palm intersects with the axis of your ear canal when you press your hand against your ear. I found I didn't have to use the 43AG's clamping mechanism, which I usually have to with on-ears to ensure a good seal against the simulator's fake rubber ear. I experimented with the position of the earpads by moving them around slightly on the ear/cheek simulator, and settled on the positions that gave the best bass response and the most characteristic result overall.

The frequency response curves correspond well with what we heard: There's a strong bass emphasis centered at 140 Hz. We also see peaks at 3 and 6 kHz, which is pretty typical voicing, but it's not enough to overcome the psychoacoustic masking of the pumped-up bass. The response in wired and Bluetooth modes is essentially the same, except for a mild bass roll-off below 50 Hz in Bluetooth mode. With the headphone in wired mode, I tried adding 70 ohms output impedance to the V-Can's 5-ohm output impedance to simulate the effects of using a typical low-quality headphone amp, and found that there was no significant difference in response.

The spectral decay plot (a new and somewhat experimental feature of our headphone measurements) shows a slight resonance around 1.4 kHz, but a lot of apparent resonance below 1 kHz.

Due to the Clio's limitations, I could measure total harmonic distortion (THD) only with the headphone in wired mode. At 100 dBA, it's a little high in the bass, about 3.5% at 100 Hz and breaking the 10% barrier between 35 and 60 Hz.

Isolation is a little above-average for an on-ear, probably 'cause of those plush, comfy earpads. It's only -7 dB at 1 kHz, but runs -20 to -29 dB from 2 to 15 kHz.

Impedance in wired mode averages about 40 ohms through most of the audio range, while average sensitivity in wired mode from 300 Hz to 6 kHz at the rated 32 ohms is 105.8 dB.

Bottom line

We've heard plenty of headphones voiced like this, including the JustBeats Solo, the Paradigm e3M (before they revoiced it), the Skullcandy Navigator (before they revoiced it), and another headphone you'll see reviewed here later this week. Clearly somebody likes this sound. But for our taste, we'd rather see the Image One Bluetooth's sophisticated, mature design married to a more sophisticated voicing.