Anyway, I decided I needed new headphones for my Sony PSP. After looking at a few options, I firgured that I was looking for something that sounded “acceptable” and was efficient enough as to be able to be reasonably loud if required. So I took a trip to the local electronics dealer, Jaycar. While skimming through the different headphones my eye was caught by the Active Noise-Cancelling Earphones. “Hmm” I thought. “hmm”

Now, I happen to know that active noise cancelling headphones are expensive. A few hundred Aussie dollars worth. But these stood out as they were only $29.95 (at time of writing). I figured that maybe, just maybe, all the required digital signal processing required for active noise cancelling to work properly just might have been squeezed into one or two processors – and that said processors were cheap enough these days to start to be included in devices at this price point. Was I crazy?

In a word – Yes. Once I got home I inserted the battery (which was included), plugged in the headphones and connected up to the PSP. I even remembered to turn the volume of the PSP down just in case the noise-cancelling processing increased the volume or something.

Once I turned on the headphones I was immediately… disappointed. This is not so much an active noise-cancelling device as a white noise generator. I guess there is some modest dampening effect – after all, white noise does tend to suppress other noises (just stand near a running tap to demonstrate this effect). But most reputable active noise cancelling devices sample the outside noise and generate the opposite in an attempt to cancel the noise. That’s not what the headphones I purchased seem to do.

All is not lost, though. The white-noise generator part of the headphones can be bypassed, and the headphones can be used by themselves. And, surprisingly, I think they sound just fine. [Edit: after an afternoon of using these things, I hate them. The left earphone has come loose and vibrates. They produce overly muffled-sound. In short: these things are crap.]

So, I originally went to Jaycar to get some headphones that worked well enough to hear the PSP in a noisy environment. I will throw away the noise cancelling part because it’s useless – and the headphones themselves are quite acceptable utterly crap.

The moral of this story : if you want noise cancelling headphones, you’re probably better off buying a good set of ear muffs.