Tartini Tones

[Artie_Fufkin]

How come no one has brought up Tartini Tones when discussing frequencies above the upper limit of human hearing?

[AxeD]

Aren't they the same as sum and difference frequencies? Hardly something that's above or under the hearing limit.
You hear them while tuning a guitar basically.

When two pure sines are playing at 1800hz and 1801hz you also hear the sum and the difference of these two.
Believe there's also other psycho acoustic effects related to these tartini tones, but this is the one I've learned.

[Samuel_L_Damnson]

Is that the sort of warbling sound you get when you play the 5th fret and the string open below it and turn the tuning pegs?

[AxeD]

Is that the sort of warbling sound you get when you play the 5th fret and the string open below it and turn the tuning pegs?

Yeah that's basically the combination tones phasing in and out.

[Artie_Fufkin]

ya, beats. http://en.wikipedia.org/wiki/Beat_(acoustics)
And what I meant in my first post was: How come, with the discussions on sample rates, lowpassing the master, and debates on whether humans can perceive frequencies above 20kHz has no one mentioned Tartini tones?

[AxeD]

How exactly does it change the frequency response of the human ear?
I don't see how it's related.

[Artie_Fufkin]

If we get a difference tone, how come when I play a 20,000 Hz sine tone and a 20,500 Hz sine tone (both which I can't hear), I still don't hear or perceive it in any way? Am I supposed to be hearing 500Hz? I feel like I'm misunderstanding this. I know the volume is oscillating at 500 cycles per second, but the way I'm reading the information on this phenomenon is that I'm supposed to "perceive" the difference in the tones.
I know the volume swells and silences and I can see it when I sum the two tones together.

[ulivolga]

I think when a fundamental pitch is played with it's third or fifth, the subharmonic tone it creates is an octave below the fundamental. An octave below 20khz is still pretty high! Also its weaker than a pure tone. I think too that since it's about harmonics, maybe a more harmonically rich wave like a saw wave would give better results? Not sure..