I have a .wav file of a piano being played at 220 hertz. When I tone this up to 880 hertz, it begins to sound "stringy". However, if I were to use the piano plugin in fl studio and play it at 880 hertz, the piano would still sound normal.
My question is why a piano starts sounding stringy at higher frequencies(although I do know that a piano is in a way, a string instrument) as well as how to I can tone up a piano audio file so that it still sound like a piano(I am hoping to find a way to programmatically tone up a piano audio file as opposed to a program)
Link to file of a piano being played at 220 hertz(from fl studio): https://drive.google.com/file/d/1bUzBVXYrKS2Mzcg4VFEoBjIXqgGz1sFk/view?usp=sharing
Link to file of the above file being sped up to 880 hertz: https://drive.google.com/file/d/1H16aydDErdBrrkDtHScfgITqrmMdi1I7/view?usp=sharing
Link to file of a piano being played a 880 hertz(from fl studio): https://drive.google.com/file/d/1sEN4nvYS6QJeU0gtOruKvQGvDoZpzTx-/view?usp=sharing