Abstract: A method and apparatus for presenting at least a portion of a musical notation of a starting point of a song to a user, including a first note or chord to be played; indicating a tempo of the song to the user; receiving from a musical instrument played a signal indicating how the musical instrument is being played; monitoring triggers and responsively to detecting a starting trigger beginning to playback one or more backing tracks; detecting the starting trigger by determining that the user has provided a starting sign independent of the apparatus; and synchronizing the playback of the one or more backing tracks using a time when the user has provided the starting sign.

Abstract: A computer-implemented method includes: providing backing track audio data, wherein each backing track includes information of at least: song tempo, tonal content that is synchronized with the backing track audio, selecting a song, receiving a real-time audio signal of the user's performance, estimating parameters, based on the audio signal, including at least: playing activity of the user, wherein detecting whether the user is producing any sounding notes with a musical instrument, tempo of the user's playing, and playing position of the user within the selected song, estimating the reliability of the estimated tempo and play position of the user, wherein a value of the reliability represents the probability that the amount of error in the estimated user tempo and play position is sufficiently small, and when the estimated reliability of the user position and tempo is sufficiently high, start playing the backing track at the user position and tempo.