Plugin to generate Frequency, sine sound wave, Win, Isadora 3

Re: [Generative music using Isadora](/topic/4781/generativemusicusingisadora)
Re: [Generating a Sine Sound Wave](/topic/2205/generatingasinesoundwave)
Hi,
I stumble over these older discussions above on generating sound, but couldn't find the (perfect) solution there.
I wish to make an installation in which a 25Hz frequency gets manipulated by movement and I would love to not have to 'outsource' the frequency generator. I of course have the option to send i.e OSC to another program (such as Abelton Live), but I feel for such a rather small task of sound generation I would like to not involve an extra program. I am thus looking for a Isadora intern solution.
In one of the older threads I found the option to just play a recorded frequency sound file and manipulate this frequency via the replay speed, this is an option, but I still would enjoy being able to define the frequency in Isadora and maybe also to know to which frequency I manipulate the sound signal.
I couldn't find any Audio Plugins for Windows (and Isadora 3) that generate a tone. So I am wondering either if somebody knows a audio Plugin that could help me with this task or has another suggestion?
(I know there have been discussion for version 3 that a tone generator would be release, but I don't think there is one yet... at least I didn't found one....?)
Thanks in advance!

@ari said:
I found the option to just play a recorded frequency sound file and manipulate this frequency via the replay speed
This is still your best option if you want to stay Isadoranative. There is not a tonegenerator plugin.
Here's a reddit post that gives a formula for calculating the pitch change based on the speed change
s = 2^(t/12)
Where t is the number of semitones you want to transpose. And s is the playbackspeed you need to play the clip at to get the desired pitch.
The other answers suggesting to look for a lineair pattern won't get you anywhere close.
A simple example is playing a clip at 200% will transpose it 1 octave up but playing it at 300% will be 1.5 octaves up. You'll have to play it back at 400% to get 2 octaves higher than the original
A second person wrote:
2^(x/12) (*100 for %) where x is the number of semitones. X is either positive if you're going up in pitch or negative if you're going down. This is for equal temperament, not just temperament.
A third person wrote:
Conversely, if I play the clip back at 137% speed, how much does the pitch go up?
change in semitones =
−12log2(t1/t2)
wheret1
= tempo before change andt2
= tempo after change 
@woland Thank you very much for the fast reply!
I am trying to wrap my head around the formula and how to apply it. I though can't yet see how the frequency in Hertz is changing (as I am not thinking in semitones).... not sure if I am just overlooking sth.
Basically as an example I would like to know if I play 25 Hertz in 200% speed, how many Hertz do i get ....?

@ari said:
can't yet see how the frequency in Hertz is changing (as I am not thinking in semitones)
This may be helpful
Chart of Musical Notes as frequencies 1
Chart of Musical Notes as frequencies 2 (It has a helpful note at the bottom: "To get the semitone frequency, multiply the note below it by 12√2 or 1.0595.")
I am not a musician or a mathemetician but my Googlefu is strong.

Also, if memory serves, the incredibly brilliant @Maximortal made an Isadorabased Theremin or synth a few years ago. Maybe Maxi can help out with some insight.
Best wishes,
Woland

https://www.meldaproduction.co...
https://www.meldaproduction.co...
perhaps what you are looking for?
best
JeanFrançois