Have you tried Riffstation Pro (free now)? It has a slow/fast knob. Was previously sold by Fender. https://www.techradar.com/news/fenders-riffstation-pro-is-now-free-get-the-chords-for-any-song-on-your-desktop Download here: https://www.filehorse.com/download-riffstation/ The Riffstation 1.6.3 download here has the same file hash as the installer that I archived 4 years ago. All good on VirusTotal as well. It's end-of-life and not developed anymore, so YMMV. It still loads on Win1