"<a href=""https://www.youtube.com/watch?v=fa28lIGuxq8&amp;t=0m16s"">0:16</a> That's what I call the censor sound. The sound I hear from trucks usually sounds more like a square wave or something", and usually sounds like D or E flat, rather than B. I've never heard one that's B/1000 hertz before in fact.