On Sun, 2006-01-29 at 13:40 +0100, Wolfgang Woehl wrote:
> fons adriaensen <fons.adriaensen@email-addr-hidden>:
>
> > There are certainly instruments that produce sound well
> > above 20 kHz. Now to get 'beats' between two of those
> > requires something non-linear - just summing them is not
> > enough. Our ears are non-linear at high sound levels, so
> > in a real performance this could happen. But I don't
> > think it will be noticeable at any sane sound levels.
>
> Still don't understand the non-linear part here :/
>
> I make 2 audio files with 400 and 500 hz sine tones and play
> them along (out of ardour). There is clearly audible beat
> frequency, a 100 hz hum and harmonics of that.
You should also get 900Hz. They're the sum & difference frequencies.
Apparently broadcast people called them sidebands? They're also the
reason that barbershop quartets get "ringing" chords.
I bumped into this page that explains non-linear distortion:
http://www.isvr.soton.ac.uk/SPCG/Tutorial/Tutorial/Tutorial_files/Web-hearing-difference.htm
bye
John
Received on Mon Feb 6 00:15:04 2006
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