I've run into an interesting problem with a iPhone rhythm game project I'm working on:
Basically the game has a scrolling score of music that you can play with your instrument at the same time. My patch detects pitches in real-time and then marks notes on the screen as correct or not.
The problem is that there is a built-in guide synth that plays each note as it scrolls (this is toggleable however). Right now I'm having the problem of the built-in guide synth scoring notes correctly without the user providing any input.
Obviously this issue goes away once the user wears headphones, but when you are playing audio on the phone's speaker at anywhere above 50% volume notes will get triggered automatically no matter what. I have tried several techniques (noise gate, some filters, minpower settings on helmholtz~ and sigmund~) that reduce the problem but not eliminate it.
That being said, I'm not hoping to completely eliminate this problem 100% (because it's most likely not possible), but I was wondering if anyone had any suggestions for kinds of techniques that could differentiate a real-life instrument from this built-in synth playing on the iPhone speaker, where both instruments are playing the same note?