MacScope II is a shareware audio software oscilloscope that works on
Mac & Windows, using the computer's 16 bit audio input.
I haven't tested this but per mrdav: "The zip unpacks correctly for me
in Tiger and after switching to Mac OS 9 I can run the application.
The menu arrangement is non-standard...the positions of the File and
Edit menus are switched from their normal positions."
DL #2 is the same as the first download, repackaged as a StuffIt
archive for convenience.