Now an important point here is that dynamic range isn’t mainly about the ability of audio gear to produce loud sounds. One reason for that is that, at most frequencies, producing loud sounds is actually fairly easy. But even if we view producing musical peaks as difficult, we still have problems at the quiet end of the volume spectrum. The problem is that music requires the ability to go from soft to loud and back again. The contrast between loud and soft is part of what gives music its dynamism. The difficulty is that we can’t simply create dynamic contrast by cranking the peaks up to super loud levels. That’s because very loud sounds are unpleasant (and ultimately cause hearing damage). So, to create dynamic contrast, we need the ability to play loud and soft. In addition, the ability to play soft sounds is key because two other essential music elements lie at the soft end of the spectrum: overtones and spatial reflections.

Once we move outside of a dedicated listening room environment, we double down on the problem of reproducing soft sounds. Not only do we have the challenge of actually reproducing small signals (not as easy to do as you might think due to friction and electronic noise), but we also have the problem of external sounds. As I sit writing this, I’m in my office. The HVAC system is coughing its way along attempting to warm the room on a frigid day. Trucks and cars buzz by outside. Take that scenario outside of an office and it just gets worse. You have train clatter, jet engine noise, and people chattering.

With in-ear headphones, some background noise reduction can be had via a seal between the headphone and the ear canal. But you can also purchase noise-cancelling in-ear headphones, with the case in point being the subject of this review: the Audio-Technica ATH-ANC23s with QuietPoint technology ($99.95). Read less

The ATH-ANC23 is designed for use with mobile devices. The cord is quite short, at around 1 meter, and is really optimized for a media player that is carried with you or perhaps attached to your clothing. The headphone’s impedance is 32 ohms, which makes these Audio-Technicas appropriate for use with iPhones and the like. The claimed sensitivity is 105 dB, but with no input level specified (this is a pretty common but unhelpful practice, since it more or less renders the sensitivity rating meaningless). However testing showed that an iPhone 4 could easily drive the ANC23 to satisfying volume levels and beyond. Read less

Loose fitting models like the Klipsch in-ear models are easier to insert. That’s partly due to the nature of the seal and partly because active noise cancelling headphones like the Audio-Technicas tend to be bigger and thus are slightly more challenging to align. The ANC23s aren’t particularly hard to insert, but they’re not the easiest either.

There is a secondary benefit of the electronic noise cancellation approach. One is that the bass performance of these headphones should be somewhat less dependent on the exact seal one achieves when inserting the earpieces into the ear canal. (I discussed this same point when I reviewed the Phiaton PS 20 NC in-ear noise cancelling ‘phones.).The Audio-Technicas do a better job of demonstrating this aspect of active noise cancellation than the Phiatons did, and as we’ll see in a moment, the ANC23 has pretty potent bass.

I found the noise reduction from the active circuitry to be impressive. At least for midrange and high frequency noise, the ANC23 gives the effect of wiping out the background noise and replacing it with very low-level hiss. You switch on the noise cancelling circuitry, and bang, the noise is almost gone. With more impulsive sounds like tapping, some sound still comes through, so the circuitry isn’t as effective if your problem is talkative office mates.

I did find that the ANC23 has one minor noise irritant. When the cables rub on your shirt, the sound is (mechanically) transmitted through the cables to the earpieces, and then to your ears. I wish the cables were a little more flexible to avoid this. I also need to mention that the cables are rather short for desktop/tray table use. Note, too, that the volume control markings are embossed in the black plastic case for the noise reduction circuitry, which makes reading the labels difficult. Read less

Above this band the Audio-Technicas seem to offer flat response, though this means highs may sound a bit subdued, since treble response is geared to blend smoothly with the headphone’s upper midrange, which is somewhat reduced in level to begin with. The result, however, is a smooth sound. Cymbals and other high frequency instruments are presented with admirable detail, though you may sense, as I did, that mid and upper treble frequencies could do to have a bit more energy. But experienced listeners may feel that such extra energy carries a price (in terms of potential upper midrange/treble glare)—a price the ANC23s avoid extracting.

Because of their active noise reduction circuitry, the ANC23s are also above average it terms of resolving low-level details. This is important for a sense the acoustic environment as well as for articulating the particular beauty of certain instruments.
I think the frequency response tailoring of the ANC23s will work extremely well as a package for a large group of listeners. If you are one of those, I think the one place you might perceive that the ANC23s come up short is in midrange refinement. Some headphones, including the Phiaton PS 20s I tested recently, just give the subliminal sense that they have lower distortion. The good news here is that the Audio-Technica’s midrange issues are subliminal “sins of omission” and not really front and center.

That leaves us with the question of value. It's your money, but at $99 the Audio-Technicas are likely to be a good deal for most buyers, assuming you like their sonic profile. The sound is warm and musical and the noise cancelling circuitry is genuinely useful. You could save a little, but you'd have to skip noise cancelling and for many applications the benefits of an extra $20 or $40 spent on active noise cancellation will reap noticeable rewards. Read less