Music Composers Unite!
In the nineties, I used to try out new composition ideas for fast pieces for solo piano by playing them slowly on the piano and recording them with a MiniDisc recorder, and then listening to the recording, to get an idea of approximately how the music would sound in the correct tempo. I'm not willing to limit myself to doing these tests with electronic keyboards when I compose for acoustic piano; I want to be able to record acoustic piano and speed it up to any speed I like. I'm sure there are more flexible ways to do this with more recent software than with the software in my MiniDisc recorder, which can only change the speed by a factor 1.5. What software is best for increasing the playback speed of a sound file to any speed of one's choice, and with no or negligible loss of sound quality? Is there any free software that can do that? If not, which is the cheepest software that can do that?
Also, suppose I'm willing to purchase a DAW: which DAWs would enable me to change the speed of a recording to whichever speed I like, with no or negligible loss of sound quality?
I don't want the pitch to change, only the speed.
You need to understand what is a MIDI score: this is the main object of operating through a DAW.
In simple terms, MIDI score for DAW is the same as traditional music score for a human player. MIDI score is a detailed written prescription of instrument key-presses with precise values of time, press strengths (called velocities) and duration. When you play, your DAW can record a MIDI score of your input. Then you can play and edit your MIDI score using a MIDI editor of your DAW. Your task would be simply changing the overall tempo of your MIDI score, which your DAW will play automatically.
The performance quality, though, will depend on the quality of your virtual piano (or another virtual instrument that you assign for playing your score). There exist numerous virtual pianos and other virtual instruments, which your DAW can play automatically according to your MIDI score.
There exist many commercial and free DAW: