I’m a huge fan of this approach, first using it for database sync testing with some soft-spoken background sounds about 1996. As the users had an unreliable internal network, they liked it so much they requested the debugging feature be left on permanently. They liked hearing sending shortly followed by receiving, in the open-plan office.

I used combinations of tones to help debug the realtime stereoscopic 3D rendering for Quicktime (OpticBOOM) I wrote in 2001. Structuring the tone sequences carefully gave me an an audible trace matching the steps of frame preparation and rendering. When you have sequences of sounds, your brain is very good at recognising a blip in the sequence.

One of the earliest debuggers I think that had this feature built in was the excellent Metrowerks Codewarrior.