On Sun, Nov 3, 2013 at 12:47 AM, grarpamp
... Unlikely the average laptop would adequately cover the airgap in this frequency range. Signal to noise ratio and packet loss are further inhibitive to data transmission.
friend and i spent a few hours earlier this week playing around with high frequency data transmission over PC speakers and microphones. my hearing is rather poor, as sounds > 13kHz are inaudible to me. $friend can hear just over 17kHz. a few normal laptops and mics were able to emit and receive in the 18kHz to 20kHz frequencies just fine, and (unsurprisingly enough) there's almost nothing in this range naturally. a side channel just waiting for use! bit rate is poor in our limited example, however. i'll leave high speed, error correcting implementations to the reader ;) best regards,