Thanks, all, for your suggestions. I downloaded SoundApp and SndConverter Pro, but they're in .hqx format. I have Stuffit Classic, which only supports .sit files. I did a little searching and found something called binunpk which is supposed to unpack hqx files. It's .dsk, and my LC tried to open it as Simple Text.

Any tips on how to unpack the hqx files? I don't have a recent Mac to do it.