You want to slow down an MP3. Fine. This is trivial. You use ffmpeg. It is the only tool you need for media manipulation on Linux.
To take your 100% speed MP3 down to 90%, you use the atempo audio filter.
Here is the command you need:
ffmpeg -i your_original_audio.mp3 -filter:a "atempo=0.85" your_slower_audio.mp3Replace your_original_audio.mp3 with the path to your input file and your_slower_audio.mp3 with your desired output file name. The atempo=0.90 part tells ffmpeg to play the audio at 90% of its original speed without changing the pitch.
That is it. Do not overcomplicate these things.
