io series provides solos, duets and songs covering four centuries of composers for the guitar and lute family. Taken from original sources, and carefully fingered for the modern player, the transcriptions are as faithful as possible to the original while at the same time offering a practical performing score. Audio is accessed online using the unique code inside the book and can be streamed or downloaded. The audio files include PLAYBACK+, a multi-functional audio player that allows you to slow down audio without changing pitch, set loop points, change keys, and pan left or right.