Phase cancelling at different frequencies

[keyboarder89]

Hey,

I have a program called Audio Toolbox for Mac OS X and it has different wave controls as well as the phase control. I have hooked an oscilloscope (2 channel) up to the stereo headphone out, so that I have one right and left signal going through. I ran several different waves messing around with it to see how it works, and I ran 2 different waves (triangle or square if I remember right) through left and right at a frequency and I changed the phase to 180 degrees. I thought the sound would cancel but it didn't. It turned out to cancel at 108 degrees. Some other frequencies also cancelled out at 252 degrees. Messed up software or can waves really be cancelled at different degrees of phase?

Thanks!
Zach

[simon5]

If it's a perfect square wave, it should cancel at 180 degrees, like a sine wave.