Here's another anti-fool who who has an interest in the inverse problem of connecting frequency amplitude signals with audible sounds coming from rotating machinery that may reveal ongoing damage that might progress to failure of vital components. We have heard supposedly non-musical machines making all kinds of audible sounds some of which approximate to real music while others are of the annoying and even threatening kind. Among the long list of our turbomachinery tunes are wind chimes, chirps, clicks, whistles, squeals, creaks, barks, water sprinkler, washing machine, card-in-a bicycle spoke, stick-in-a-picket fence,brush-on-a-snare drum, knocks, static, etc....etc. Many attempts to fathom the cause of these "symphonies" using high resolution signal analyzers has failed to fully reveal the physical state of the machines producing these sounds. However, we are inclined to believe that you need many harmonics of a particular kind of source along with plenty of modulation sidebands. If you could control the relative amplitudes of the various harmonics then, perhaps, you could produce many different sounds using the same source ingredients. Unfortunately, it is the machine that controls the waveform distortions that vary the modulated harmonics that make the sounds and if you've got a very "loose" rotor inside the machine you have infinite possibilities for musical or non-musical concertos. I'm looking into the internet "music" world and finding much good stuff that may eventually help. I'll have to look up my music sources further to contribute to your metronome problem. vanstoja
