I have been trying to record some music I composed on my guitar,] using Audacity. I played some difficult passages slowly so I got clear notes and the recording sounds fine. But when I use the tempo change feature to bring the speed up (30% or so) to match the rest of the piece the result is "muddied" to the point of being unusable. Any hints on this. Maybe I should try changing the tempo many times, say 1 % at a time, or change pitch down and then use time change to bring it and the pitch back up, or maybe the tempo function will work better if the file is bass boosted or compressed or amplified first, or maybe I should superimpose the original bar by bar, or use a third party add-in etc etc. Suggestions?