I know the googling is a bad idea, but I don't think I'm explaining the whole cry thing very well.
Am sure it's nothing to worry about, but what I mean is it isn't a cry he does every so often, or one of his range of cries, it's EVERY sound he makes is about two octaves above normal, even the happy noises, and sounds mostly like a car alarm or a whistling dolphin bath toy (if you have one of these, you'll know what I mean).
And I know I'm not being a paranoid mum, because he doesn't sound like any other baby I've ever met, including DS1, and whenever other people hear it they always say 'Christ, what was THAT?' and when I say it was the baby they refuse to believe me. Everyone always comments that they've never heard a baby make that noise, even people with loads of experience with children.
So although I'm sure it's not a sign of anything wrong, it's still rather odd, iyswim.
Hmmm. I think I'll have to post a video or MP3 of it, really, won't I?