Gerhard Fiedler wrote: > How does that relate to the fact that (with constant pressure amplitude) > the speed amplitude increases with increasing frequency? Fact? I don't see why maintaining second-order derivative amplitude at some level, you are necessarily getting first-order derivative amplitude increasing with increasing frequency. As for me that's quite the contrary. Regards, MS -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist