Relative pitch implies some or all of the following abilities:[1] This last criterion, which applies not only to singers but also to instrumentalists who rely on their own skill to determine the precise pitch of the notes played (wind instruments, fretless string instruments like violin or viola, etc.
[2] Computer-aided ear training is becoming a popular tool for musicians and music students, and various software is available for improving relative pitch.
[citation needed] Some music teachers teach their students relative pitch by having them associate each possible interval with the first two notes of a popular song.
Indian musicians learn relative pitch by singing intervals over a drone, which Mathieu (1997) described in terms of occidental just intonation terminology.
[3] [page needed] Many Western ear training classes used solfège to teach students relative pitch, while others use numerical sight-singing.