Hi,

It's very easy to get at least 3 different noises from the standard 5V buzzer : I have click/bip/beep routines in my stuff : just turn it on for different lengths of time. You could use 4 fast clicks for a "connect" noise ("Kirk to Enterprise"), etc. The human using the device will soon get used to all the different sounds!
Story 1 : a computer at work long ago had a speaker on the data bus; you could tell what program was running from the noise! Some clever stick wrote a 4-voice compiler for the thing!
Story 2 : I've even seen one of these cheap buzzers in a modem used as the "speaker"! It worked fine until I got fed up with the racket & put a drop of Super Glue in it!).

Regards,

Richard