How to do Frequency Scaling on an Audio File
Everything is possible with advanced technology, due diligence and perseverance. To discuss the means to reach your goals requires even more detailed description of target scenarios.
If you have a pure tone -- I mean, a musically pure single note performed by a good musician with a quality instrument or an opera singer -- you can analyze this sound by spectral methods and even real-time-process this sound in order to shift its frequency or change its overtones any way you like. Then, you can implement these transformations with a digital signal processor or conventional computer.
The task is more difficult, if you have a musical piece recorded and want to process individual parts of the performance through submitting them to a &quot;pitch scaling&quot; as defined in your Correlogram Museum reference. Even to &quot;pitch scale&quot; a recorded or live-performed triad, not a single note, is an algorithmic and methodological challenge.
In the Correlogram Museum examples, the performer plays on a synthesized piano-like instrument. The DSP unit most certainly takes part in producing the sounds of this instrument, but the pipeline of sound production is inverse w.r.t. your scenario: the sound is generated with &quot;scaled&quot; overtone frequencies, whereas you have a sound with overtones prepared early and want to &quot;post-process&quot; the sound in order to change its overtone content.
I admit there are design projects pertinent to the scenario of your question. Ask colleagues, browse the literature, search the Internet.