DSP Robotics Support

Thanks HughBanton. I will have a look

I sorta get what u mean Halon,
coz the pitch is a non-linearity.
-but no matter what pitch you use,
it will still be some pitch in tet too(counting pb).
I want to use something like->
1
1.125
1.166
1.25
1.33
1.5
1.66
1.75
1.875
2
sometime for kicks

Yes. Liner detuning, or Beat Frequency is from Moog Sub 37 i believe. Detune osc 1 a couple of cents against osc 2 doesnt get you that 'phase-y' sound that you normally would. It stays 'in tune' even if the oscillators are detuned against each other.

Halon wrote:Yes. Liner detuning, or Beat Frequency is from Moog Sub 37 i believe. Detune osc 1 a couple of cents against osc 2 doesnt get you that 'phase-y' sound that you normally would. It stays 'in tune' even if the oscillators are detuned against each other.

I have no clue what is meant with "beating", but I found two statements. One is this:
https://synth-diy.org/pipermail/synth-diy/1997-July/142367.html

And on a Moog forum I found this half-sentence about the Sub 37: "unlike BEAT FREQUENCY which will keep the difference, in Hz, the same across the whole range of the keyboard"

From these two I conclude that what you are looking for is not relative detuning as it is implemented in pretty much all synths nowadays (detune by octave, half-note and cents, which are all relative measures), but absolute detuning, which is a fixed amount of detuning that doesn't change with the notes played.

Relative detuning:
Note played is A4 = 440 Hz. Cents refer to a full note, so -50 mean a half note down, +50 a half not up. We set detuning to -50, and the resulting Frequency is 415.3 Hz = Ab4
Note played is A3 = 220 Hz. Detuning stays at -50 cents. Resulting Frequency is 207.65 Hz = Ab3

Absolute detuning:
If I understand it correctly, then you would have the same distance in Hz. I don't know the root of this Moog tuning (and you need one). For this example I assume A4 as the root. The difference from our -50 cents detuning is 440 - 415.3 = 24.7 Hz. This is fixed, so for the note A3 the detuning of -50 still means -24.7 Hz, which results in 195.3 Hz (instead of 207.65 in relative detuning). That frequency is just below G3, btw.

Important for this absolute detuning is to find the root. The frequency that is used to define the difference per cent. I can't help you with that, but I hope this gives you something to work with?

I’m still not too clear on what Halon is looking for.
You’ll always get beating if you detune 2 identical waveforms that are mixed. This is basic physics really; constructive and destructive interference takes place. If the frequency differs you will get addition which will nearly double the wave size or subtraction which will nearly eliminate the sound as the signals go in and out of phase. This happens on a cyclic basis dependent on the difference in Hz.

This is most audible when the two oscillator signals have identical waveforms, and least noticeable if the two waveforms are very dissimilar.

I’ve attached a simple schematic where you can set a beat frequency which holds over the entire keyboard range, including pitch bending.

Is this the desired goal?

Cheers

Spogg

tulamide wrote:

Halon wrote:Yes. Liner detuning, or Beat Frequency is from Moog Sub 37 i believe. Detune osc 1 a couple of cents against osc 2 doesnt get you that 'phase-y' sound that you normally would. It stays 'in tune' even if the oscillators are detuned against each other.

I have no clue what is meant with "beating", but I found two statements. One is this:
https://synth-diy.org/pipermail/synth-diy/1997-July/142367.html

And on a Moog forum I found this half-sentence about the Sub 37: "unlike BEAT FREQUENCY which will keep the difference, in Hz, the same across the whole range of the keyboard"

From these two I conclude that what you are looking for is not relative detuning as it is implemented in pretty much all synths nowadays (detune by octave, half-note and cents, which are all relative measures), but absolute detuning, which is a fixed amount of detuning that doesn't change with the notes played.

Relative detuning:
Note played is A4 = 440 Hz. Cents refer to a full note, so -50 mean a half note down, +50 a half not up. We set detuning to -50, and the resulting Frequency is 415.3 Hz = Ab4
Note played is A3 = 220 Hz. Detuning stays at -50 cents. Resulting Frequency is 207.65 Hz = Ab3

Absolute detuning:
If I understand it correctly, then you would have the same distance in Hz. I don't know the root of this Moog tuning (and you need one). For this example I assume A4 as the root. The difference from our -50 cents detuning is 440 - 415.3 = 24.7 Hz. This is fixed, so for the note A3 the detuning of -50 still means -24.7 Hz, which results in 195.3 Hz (instead of 207.65 in relative detuning). That frequency is just below G3, btw.

Important for this absolute detuning is to find the root. The frequency that is used to define the difference per cent. I can't help you with that, but I hope this gives you something to work with?

Yes absolute detuning seems to be what im after. I'll play around with that. Thanks for the explanation tulamide.

Spogg wrote:I’m still not too clear on what Halon is looking for.
You’ll always get beating if you detune 2 identical waveforms that are mixed. This is basic physics really; constructive and destructive interference takes place. If the frequency differs you will get addition which will nearly double the wave size or subtraction which will nearly eliminate the sound as the signals go in and out of phase. This happens on a cyclic basis dependent on the difference in Hz.

This is most audible when the two oscillator signals have identical waveforms, and least noticeable if the two waveforms are very dissimilar.

I’ve attached a simple schematic where you can set a beat frequency which holds over the entire keyboard range, including pitch bending.

Is this the desired goal?

Cheers

Spogg

Thanks Spogg. Downloading now. I'll let you know if this is what im after.