Gerard McMullon, Facebook asked:
Why is it that some stations become tiring to listen to after even a short period of time - e.g. I can't listen to Radio 1 for long but used to and my daughter finds no problem with the signal.
John - It’s all to do with the amount of compression and the type of compression that is put into the signal. As I said earlier, audio processors nowadays are very clever devices, multiband devices, so they chop up the audio spectrum into different chunks, and they process them separately. You can put an amount of basic compression in, and you can add clipping. Clipping in moderation is fine because it adds intelligibility. In fact, old telephone systems used to have lots and lots of clipping on it, which made it nice and easy for people to understand what was being said, even on a really crackly horrible line.
Chris - This is where, if you got a wave, if you're literally just chopping the top off the wave, isn’t it, to make it a bit quieter.
John - That's right. Exactly that. Now, that in moderation is fine, but it can be quite tiring after quite a short period of time. Normally, around about 5 to 10 minutes, some people start to notice the clipping effects in the audio processing that's used. Unfortunately, a lot of broadcasters, when they put the audio compression in, do it for an instantaneous reaction to listeners who perhaps are just tuning down their dial, they find their radio station, and they think, “Wow! That's loud! That's very impressive” and are going to hang on in there for a bit. That's all well and good, but very quickly, this fatiguing effect can take over, and it affects some people more than others. That's the strange thing, you might find one person that doesn’t notice the fatiguing effects. But other people find it really, really distracting and disturbing, and want to tune away very quickly.