On a recent long airplane trip, I sat next to a guy who seemed a little more relaxed than those around him. He was wearing headphones, but rather than tapping his feet or swaying to the music, he was just comfortably resting. A closer look showed the headphones weren’t plugged in to any sound source!
Eventually we started chatting and he told me his secret. He was wearing Bose Noise Canceling Headphones. He let me try them on. I put them over my ears. This alone helped quell some of the sound. Then he flicked a switch. At first nothing happened, but then after a few seconds the floor dropped out of the noise level. I hadn’t noticed how loud the engines were, but now that they were vastly attenuated I couldn’t believe that I could even keep my sanity with such a racket.
The headphones aren’t magic. It’s not like I was in silence, but it was the difference between an emerging headache and feeling suddenly at ease. Amazing.
Geeks will know that the secret is tiny microphones in each ear cup that feed a signal to a microprocessor which then adds an opposite phase cancellation signal to whatever the music source provides. To do it completely in real time is an impossible physics and computational problem even before you add in all the extra psycho-acoustic corrections, but the imperfect approximation was a major advantage.
Before my next long airplane trip I stopped by a music store but they didn’t carry the Bose model. I ended up with a pair of Sony in-ear plugs. Trying them at home was disappointing. If there isn’t a lot of ambient noise to cancel out, the circuitry can actually make the noise level worse. (The phones have an on/off switch for this reason.) Even on the plane it took a while to get it working right. I had to jam the plugs further into my ears than seemed right, but once they were properly situated, the magic happened again.
Here’s the big difference. On my first airplane trip with normal headphones, I could easily listen to audio books on my iPod, but music was tough, especially if there was large dynamic range as with jazz or classical. On my second trip, I could enjoy a cello concerto or a jazz vocalist as easily as I could listen to my eclectic collection of pop songs. From now on, I won’t fly without them.
Why stop at canceling sound waves, though? I can just imagine teams of Japanese engineers hunkering over their lab benches working on ways to cancel light waves, tsunamis, or life regrets. What a product that will be! Batteries not included.
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