Mention noise-cancelling headphones and most people think of large, over-ear models like the Bose QC15. Comfy as those big cans can be, they’re waaaay too big to slip into a pocket or purse. But not all noise-cancelling headphones come in cases sized like jumbo donuts at the State Fair. In fact, a few manufacturers have added noise-cancelling technology to their in-ear monitors (IEMs), using a little “lump in the line” to house the needed electronics.
One might fairly ask, though: Do IEMs really need noise cancelling? After all, when used with tips that fit your ears properly, IEMs completely seal off your ear canals. However, IEMs do most of their noise-blocking at frequencies above 1 kHz. Below that, they’re not so effective at keeping the noise out.