I'm trying out ToneLib Jam (on Linux), and it looks promising, but I ran into some issues. As soon as I open it, I get a loud feedback screeching sound, and have to mute my speakers. Is there some setting that needs to be changed? What file types are supported? On the ToneLib page, it says "Find the tabs (or music sheet) of your favorite song or a music exercise, load it and start playing!" So I found a PDF file of a song I want to learn and tried to load it, but got a message about unsupported file type. How much does ToneLib cost? On the purchase page, there are two links and two prices, but I'm not sure which one is for Jam. Thanks!