Change pitch option

[jshonfield]

When I select the change pitch option from the 'Effect' drop down menu it gives several options to change the pitch. For one of them it shows a frequency value in Hz with a box beside it where you can change the frequency to whatever you want. But what measure of frequency is this? Is it the fundamental frequency of the sound, or the maximum frequency, or an average frequency?

[steve]

it shows a frequency value in Hz with a box beside it where you can change the frequency to whatever you want. But what measure of frequency is this?

This is the "Change Pitch" effect.
This effect will make the pitch of the selection go up or down by the amount that you set, while keeping the tempo (approximately) unchanged.

The effect is actually increasing or decreasing all of the frequencies according to a fixed ratio. For example, if you set it to +50%, then the ratio of the original pitch to the pitch after processing is 1:1.5
(The original pitch is 100%, so +50% makes 150%, That is 100% to 150% = 1:1.5)

However, what does that mean to a musician? Ask a singer to sing a note, then ask them to sing a note that is 50% higher and they will look at you blankly. On the other hand, if you ask a singer to sing a note, and then ask them to sing a note that is a "perfect 5th" higher, then they will probably know what you mean.

Similarly, if you ask someone to play a note on a piano, and then ask them to play a note that is 7 semitones higher, they will probably be able to count up the piano keys and play the note that is 7 semi-tones (a perfect 5th) higher.

As it happens, a perfect 5th is approximately 50% higher in frequency than the starting note. This applies to whatever the starting note is.

The various ways of selecting the pitch change are really just for convenience. If you have a piece of music and you want it to be a semi-tone lower, then you can select that in several different ways, but with identical effects:
Pitch
From A to A#
From A# to B
From C to C#
....
Semitones (half steps) = 1.00

Frequency (Hz)
From 440 to 466.164
From 466.164 to 493.884
From 523.251 to 554.365

All of the above are exactly the same as the ratio of 1:1.05946 which is an increase of 5.946%

[jshonfield]

I'm using the Audacity program not for music but for research on squirrel vocalizations. In my case changing the pitch by semitones has no real meaning. I want to know what that measure of frequency is that comes up in the Change pitch box? I suspect it might be fundamental frequency, but I'd like to know for sure.

[steve]

I want to know what that measure of frequency is that comes up in the Change pitch box? I suspect it might be fundamental frequency,

No, it's arbitrary.
For example, doubling the frequency is a pitch increase of an octave - that is the case for all frequencies.
100% increase in pitch changes 100Hz into 200Hz, 150Hz into 300Hz, 1kHz into 2kHz, and so on.

In my case changing the pitch by semitones has no real meaning.

So what kind of measure has meaning?
Percentage change?
Frequency x "this much"?

I'm not sure how I can explain more clearly. What exactly are you trying to do?