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Re: two sine tones simultaneously within one critical band

Bob Masta wrote:

> I am completely at a loss to understand how you arrived
> at your last formula.  It appears that you have not simply
> added the pressure waves, but multiplied them.

cos(2pi*t) * cos(100 * 2pi*t) = cos(99*2pi*t) + cos(101*2pi*t)

This can be derived using:

cos(x1)*cos(x2) = 1/2*cos(x1-x2) + 1/2*cos(x1+x2)

Another explanation can be: two frequencies (99Hz and 101Hz) can be seen as one absent carrier (100Hz) modulated with a modulator (1Hz).

br, Piotr Majdak

-- Piotr Majdak Acoustic Research Institute Austrian Academy of Sciences Reichsratsstr. 17 A-1010 Wien Tel.: +43-1-4277-29511 Fax: +43-1-4277-9296 E-Mail: piotr@xxxxxxxxxx WWW: http://www.kfs.oeaw.ac.at