If you’ve read Playback Editor Chris Martens’ recent coverage of custom-molded in-ear headphones (from Westone, JH Audio and Sensaphonics), you’ll know that the level of noise reduction from in-ear headphones is not a given. To put it numerically, if the noise in the environment is at, say, 80 db (a reasonable number for the interior or an airplane or train, with peaks rising well above that average level) and ideally you’d like the environment to have a background noise level of 30 db., then you need 50 db of noise reduction from your headphones. You probably won’t get that much, but with well-known brands quoting 30-40 db of noise reduction, you can see that there is room for even more silent backgrounds.
The objective here isn’t silence for the sake of silence. The spatial cues in music and harmonic signatures of instruments consist of very small signals. Mask those with noise and you lose some of the magic. With that thought in mind, we’ve recently tested the Phiaton PS 20 NC in-ear headphones with active noise-cancelling features.
While most high-end in-ear headphones rely on mechanical noise reduction to block external sounds, the Phiaton PS 20 NC in-ears also use electronic noise cancellation to do the job. This should allow great noise reduction and could also help tune the noise reduction to particularly difficult frequencies (e.g. the 125 Hz drone of an aircraft engine).
Phiaton claims that the Noise Blocker technology attenuates 95% of the external noise from the environment. In addition, the signal processing circuitry is set up so that the headphones continue to work even if the Noise Blocker battery runs out of power.
The PS 20 NC is designed for use with mobile devices. The impedance is 26 ohms, which makes them appropriate for iPhones and the like. The sensitivity is specified at 101 db, but with no input level. However testing showed that an iPhone could easily drive the PS 20 NC to satisfying volume levels and (gulp!) beyond.
The active-plus-passive noise cancelling approach is the one typically used by larger over-the-ear headphones, of course, and it has also been applied on occasion with in-ear ‘phones. With the PS 20 NC, part of the focus of the active technology is on ease of use.
First, by relieving the earphones of the need for mechanical resistance to outside sounds, the PS 20s don’t have to have quite as tight a seal to the ear canal. This should allow the designer to create a more comfortable earphone, at least when compared with those models that create pressure points (a problem, in my experience, with some models in the excellent sounding Etymotic line). In our early testing, I’d say that the comfort level of the PS 20 is well above average. My comfort reference is the Klipsch Image X10i among in-ear ‘phones, and I’d say the PS 20s are about 90% as comfortable. However, the oval shape of the Klipsch earpiece still distributes pressure more evenly, and thus the Klipsch in-ear models are easier to insert.
There is a secondary benefit of the electronic noise cancellation approach. One is that the bass performance of the PS 20s is somewhat less dependent on the exact seal one achieves against the ear canal. This advantage varies with the earphone we’re comparing against, but it is there. I like being able to insert the earphone and not have to play around with it to get the seal just right (both to achieve adequate bass and balanced sound between the left and right earpieces).
Other than that, the PS 20 NCs have a small electronics box in line with the signal cable. This little box has a clip to go on your belt, or it can rest on a table next to you your source device. Overall, the signal cable is about six feet long, which is a bit more than you might need, but at least this offers some flexibility. A small carrying pouch is also included, as are ear tips of various sizes.
I found the tips easy to insert in the ear canal, but the larger than average driver housings require some dexterity to maneuver around my ear lobes, but you learn to deal with this. Once inserted, the low-pressure seal is quite comfortable (your mileage may vary, of course, due to differences in ear shapes).
I found the noise reduction from the active circuitry to be appreciable, but not huge. As a guess, I’d say the impact is in the 6-9 db realm. That is a significant gain if the pure mechanical seal is about the same as with other in-ear headphones. I’d say the seal with the PS 20 NC is a little less attenuating, so the net result is about the same attenuation at the better non-custom in-ears. Hence my emphasis on the comfort gained with this approach.