Abstract: A karaoke user's performance is recorded, and from the recorded file of the user's rendering of the song, the notes, i.e. the sung melody, is compared with the notes, i.e. the melody, of a reference file of the corresponding song. The comparison is based on an analysis of blocks of samples of sung notes, i.e. of an a cappella voice, and on a detection of the energy envelope of the notes, taking into account pitch and duration of the notes. The results of the comparison give an assessment of the performance of the karaoke in terms of pitch and note duration, as a score.