I am here defending the science..
Then a quick read about it would have told you that the science works because the two ultrasound beams carrying the sound information do not allow the sound out until they are interfered with by something solid like a wall or the human head.... This would also include a pane of glass. Thus, if Tracey is inside his house it's going to be pretty hard to keep him constantly in a targeted beam that isn't interfered with by walls, windows etc. As soon as the beams become interfered with then anyone in the close vicinity will be able to hear the same voices hence the potential application for surround sound without rear speakers - aim the beams at the wall behind the spectators and the sound emanates from behind them because the rear wall has interfered with the beams. According to the bits of Tracy's story I have read only he seems to be hearing the voices.

Tracey is doing the perfectly normal thing. He has determined that there _is_ a problem, however, he has decided to make information fit the problem rather than properly experiment to determine the actual cause of the issue.

This, of course doesn't make Tracey technically inept. It does, however, make him a bad scientist.

I am here defending sanity.....