Question on pitch shifter settings

[SparkySpark]

Hi,

I have pitch shifting available in my multi effect plugin. I am wondering about the settings in the MUX pitch shifting modules.

I tried to set one pitch shifter to a fifth above the played sound, and another one on an octave above.

What surprised me are the settings: a fifth above is about 95 percent on the module knob, and an octave about 178 (if I remember it correctly), hence I used two pitch shifters in a row for an octave.

The octave sounds rather in tune at all times, but the fifth differs a bit depending on note height (or something else).

I guessed that an octave would be 100 percent. Two questions:
1. Are there any precise values and
2. technically, how can an octave not be 100 percent?

Just curious!

[AndreasD]

There are no precise values. At least I could not figure out a way. If anyone has an idea, let me know.

The principle is the use of the Doppler effect, meaning you modulate a delay to get shorter=pitch up or longer=pitch down. As you can not get shorter delays than zero and don't want hour long delays, there are 4 delay lines that cycle the delay modulation. The delay modulation is 90 deg phase shifted and then cycle crossfaded. So you never hear when a delay reaches the endstop and start over (=click).

The pitch setting is simply the speed setting of the multi point envelope global speed, which stops at 100%. That results in a certain pitch shift. So the up/down percentage is not related to the pitch but to the envelope speed.
If you edit all envelopes (pitch and cosin) to be shorter, you can get faster changes, which result in higher pitches. My main stumbling block towards exact pitches was, that the envelope speed change is linear and pitch is exponential.

I hope this helps

[SparkySpark]

Thanks! So in other words it works rather well in one octave but not in a much higher or lower? I'll have to try that myself.