In an example on the wikipedia section on Binaural Beats it says that two sine waves heard as separate signals, one in each ear, which differ by 10 Hz will produce the perception of a 10 Hz difference tone.
Is that possible? I had always heard the lower threshold of pitch perception was around 20-30 Hz. So 10 is right out, right? Or is the mechanism of (ap)perception not bound by the same limits as the sensory apparatus?