steve@brl-bmd@sri-unix.UUCP (09/02/83)
From: Stephen Wolff <steve@brl-bmd> Yes but......... There is the well-known binaural experiment by J. C. R. Licklider (late '50s?) in which a `white noise' source fed one ear directly and the other ear through an `all-pass' filter (i.e., a filter with frequency-independent unity amplitude gain but frequency-dependent phase shift). Superposed on the background hiss, subjects reported hearing a pure tone at the filter's cross-over frequency.
DCP@MIT-MC@sri-unix.UUCP (09/02/83)
From: David C. Plummer <DCP @ MIT-MC>
Superposed on the background hiss, subjects reported hearing a pure tone at the
filter's cross-over frequency.
OK, I give up. What is(are) the currently accepted reason(s)?
Is it an illusion, is it because the ear can determine phase
shifts, or is it because the act of phase shifting is actually
modifying the pitch? Causailty says you can't correctly phase
shift random noise (which I think 'white' noise is) without doing
something to the signal. As an possible anology, suppose you
wanted to phase shift middle C. Depending on which direction you
go, you actually slide the C up or down in pitch slightly and
then shift it back to C. It is not middle C throughout the phase
shift process.