[sdiy] Harmonic content of the "sigmoid" half-sine wave

[Aaron Lanterman]

On Jun 3, 2009, at 12:15 PM, Scott Nordlund wrote:

>>  think you need some sort of nonlinearity for the difference tones  
>> to come out.    The ear (and/or brain) isn't necessarily perfectly  
>> linear though.

This is true... some multiplicative tyoe mixing can occur in the  
brain. It's a very very subtle effect, though. Ian Fritz has posted  
about this in the past.

>>  A ring modulator replaces the original frequencies with the  
>> difference tones.
>
>> So is the suggested fundamental not there, or is it created by the  
>> total
>> interaction of the original sine waves, their least common  
>> fundamental
>> frequency, ( even though not present in the generation of the  
>> waveform )
>> and represented by the resulting wave form?
>
> We can hear the fundamental, it isn't actually represented in the  
> signal, but I believe it's the result of our perception

Again, that can happen, but in the case of the "sigmoid" wave the  
fundamental really is there.

- Aaron