Preserving domestic harmony often means keeping quiet. This usually involves shutting up during arguments. However, what I’m actually referring to is the occasional need to avoid playing the hi-fi at earbleed sound levels.
Fortunately, the rise and rise of personal music players has allowed listeners to keep their Metallica worship largely to themselves. And as the players have flourished, so have earphones.
In-ear designs have dominated, but there’s still a market for more conventional types with a headband. Now, I’ve owned several models of Sennheiser headphones over the years and still use their legendary el cheapo HD 414s. In sound-equipment images of the 1970s and 80s, the 414’s canary-yellow sponge earcushions are a distinctive feature of everything from aircraft cockpits to recording studios.
Amazingly enough, you can still get spares. I was able to find a replacement sound capsule when one of the pair failed. Last year a Web enquiry landed me two pairs of foam cushions (a good thing – as the old ones perished, it began to look like I had yellow dandruff).
So, on a recent long-haul flight I was intrigued to see the Sennheiser name on my in-flight ’phones, HDC 55 noise-cancelling units. Like my 414s, they’re “supra-aural”, which is to say “on-ear”. Unlike the 414s, though, they’re compact and discreetly black.
The big difference is in the little transducers mounted on their outer surfaces. They emit a high-pitched whistle. What they’re doing is emitting sounds 180 degrees out of phase with the frequency band that air passengers regard as noise – namely, the constant racket that reassures you that you are still flying. In theory, two frequencies 180 degrees out of phase, played simultaneously cancel each other out. To be specific, the makers claim to reduce noise by 10 dB between 300 and 900 Hz.
And in practice?
Wonderful. High fidelity it ain’t, but there’s no question that noise cancellation cuts down on external sounds. Blocking off the transducers with a fingertip restores the background noise. With cancellation active, what’s left is a soundtrack that, for once, you can actually hear. In the case of Eddie Murphy’s , I’m not sure that was such a great idea, but I certainly appreciated the effect while watching the Coen brother’s from Air France’s “classics” selection.
What really struck me was that clearer sound means you don’t have to play the soundtrack at high volume to compete with background noise. In our noise-polluted environment, that’s worth something.