Re: Binaural Beats

[rene beekman <rbeekman@xxxxxxxxx>]

From: "Kingsley Ash" <kingsley@xxxxxxxxxxxxx>
>Has anyone come across these before?

From: BJM <bent@xxxxxxxxx>
>Oh, and I don't know what folks are talking about with all the
>psychological and perception stuff. Beating is certainly a physical and
>observable phenomenon.
....
>To prove it to yourself, generate the two frequencies in a
>sound editor (with a wave form display... like sound forge or peak) and
>then mix them together... voila, beautiful, egg-shaped beats.

from the msp manual, page 65, tutorial 4 - 'Fundamentals: Routing Signals':
Philosophical tangent: It can be shown mathematically and empirically 
that when two sinusoidal tones are added, their interference pattern 
recurs at a rate equal to the difference in their frequencies. This 
apparently explains why we hear beats; the amplitude demonstrably 
varies at the difference rate. However, if you listen to this patch 
through headphones - so that the two tones never have an opportunity 
to interfere mathematically, electrically, or in the air - you still 
hear the beats! This phenomenon, known as binaural beats is caused by 
"interference" occurring in the nervous system. Although such 
interference is of a very different physical nature than the 
interference of sound waves in the air, we experience it as similar. 
An experiment like this demonstrates that our auditory system 
actively shapes the world we hear.

<http://www.cycling74.com/>

------------------------------