Cookie, do you thing that an old Amstrad computer might be able to do it?
We have one (8mhz, 4colour monitor, around 648kb of ram), and there is an application named hearing.exe (not the same with the one i posted earlier) that plays various frequencies from the pc speaker and by doing various tests, it displays the average frequency you can hear.
I remember the speaker making (really?) high frequencies that I could just hear (dont remember the frequency range).
Do you think that these old speakers could produce high frequencies? (lets not forget that the old computers could only make music from the speaker, so they might needed some more frequency ranges)
Also, I don't remember hearing any clicking sounds...
I might try and fetch that application, but the problem is, that that computer supports only 5" ( not sure about the size, but you know, they are the "big" ones
), so I dont know where I could find that type of drive nowdays...
/ 
