First of all, since the audio file is an analog signal, it is very laborious to change its pitch, and the effect after the change may not be ideal. Among various audio processing software, there are not many that can change the audio pitch, and the effects are different. GOLDWAVE is pretty good. With GOLDWAVE you can change the pitch without changing the playback speed. I don’t know which version you are using. I am using the V5.25 version. The method is: Effect-Pitch. There is a “Keep Beat” box at the bottom of the pop-up dialog box. Check it. The FFT size is set to 8. Although the sound quality is lost after processing, the purpose is achieved after all.