Re: two sine tones simultaneously within one critical band

[Reinhart Frosch <reinifrosch@xxxxxxxxxx>]

Hello Pete,

At the beginning of Chapter 17 of the book "Signals, Sounds, and 
Sensation" by William M. Hartmann (Springer, 1998), entitled
"Beats and Amplitude Modulation", it says:

" [...] Suppose that two sine tones, having the same amplitude
and having nearly the same frequency, are added together. [...] "

That agrees with your second example (and also with the
topic of the present debate, "within one critical band") but differs 
from your examples one and three.

Another sentence from the mentioned chapter by Hartmann
(related to earlier postings):

"The beat phenomenon is not the result of human hearing, 
nor is it the result of nonlinear processing."

There is no confusion, I think, if in the present context of two 
simultaneous sine-tones having nearly equal frequencies one defines a 
beat as a sound level maximum, and if one denotes the rate of such 
maxima as the "number of beats per second" or as the "rate of beats". 
The term "beat frequency" is correct, too, but may be misleading.

Reinhart.

>-- Original-Nachricht --
>Date:         Sun, 9 Oct 2005 13:11:06 +1000
>Reply-To: pfreihof@xxxxxxxxxxxxxxx
>From: Peter <pfreihof@xxxxxxxxxxxxxxx>
>Subject: Re: two sine tones simultaneously within one critical band
>To: AUDITORY@xxxxxxxxxxxxxxx
>
>dear list,
>
>I'm not quite sure if everyone including myself means the same 
>when talking about (monaural) beats.
>May I express my thoughts through the following three examples:
> [...]


Reinhart Frosch,
Dr. phil. nat.,
Sommerhaldenstr. 5B,
CH-5200 Brugg.
Phone: 0041 56 441 77 72.
Mobile: 0041 79 754 30 32.
E-mail: reinifrosch@xxxxxxxxxx