Are PC soundcards accurate enough for generating precise binaural beats?
Yes. Because both channels (left and right) are absolutely synchronised, the only error that can creep in is an error due to the sampling rate clock. If your sample rate clock is running at 44200Hz instead of 44100Hz (unlikely, but I’ll use this as an example), this would give a 0.2% error in the frequencies. However, it would give exactly the same error in both left and right, so it would only give a proportional change in the beat frequency. In other words, if your soundcard clock is running 0.2% fast, all your binaural beats will also be 0.2% higher. However, this is not significant (1.002Hz instead of 1.000Hz) — at least not as significant as it would be if you used two PCs, one for the left channel and the other for the right. In that case, the 0.2% error in the carriers (150.3Hz instead of 150.0Hz) would be highly significant — 0.3Hz error in one channel means your binaural beat would be anywhere between 0.7Hz and 1.3Hz. This is the kind of problem that people have had to worry
