I've looked at the documentation at the following URL:

http://www.xuduo.cn/Tutorial/Manual_en/asnd_tune.htm

It's not clear how this is working. I assume that snd_tune changes the frequency by simply modifying the playback rate. If so, this will also change the duration, which is undesirable. I suppose that I could make the sound longer than what's needed, and then use a combination of snd_tune() and snd_stop() to achieve the effect that I want, but this would be ugly. I'd like to see a cleaner mechanism for producing a sequence of tones.

Thanks!