In some cases, the distinction between popular and art music has been blurred, particularly in the late 20th century. As a matter of fact, minimalist music and postmodern music in particular got closer to popular music and rejected older cleavages. Reversely, some popular experimental musicians also developed a special interest in the minimalist and postmodern approach and so they have converged with art music with regard to certain aspects of their music. Therefore some may consider certain forms of popular-based music such as art rock art music. However, in the strict, original sense these forms of music cannot really be regarded as pure erudite music because they do not match most of the criteria. Besides, it must be noted that many fans of experimental popular music (such as art rock and avant-garde metal) tend to mistake the sense of the word art music. They tend to use it in another sense. In their conception the art music concept is used to refer to authentic and creative music as opposed to commercial music. Hence, use of the term “art music” sometimes leads to misunderstandings.
However, other cultural classical traditions may refer to oral transmission. For example, Indian classical music is transmitted mainly orally from master to disciple, despite its typically greater sophistication of rhythmic and melodic frameworks than western classical music. Reliance on notation alone is believed insufficient to capture the exact pitches or finely nuanced ornaments demanded of classical Indian musicians, who typically act as composers as well as performers of preserved compositions. Notation in Indian music is regarded as only an aid, not a substitute, to oral transmission from master to disciple. Treatises on the structural and theoretical considerations underlying Indian classical music have been available for millennia, notably the Natyashastra of Bharata, dated to between 200 BC and 200 AD. Some Western classical composers, notably Messiaen, relied on Indian rhythmic frameworks for their rhythmically more sophisticated compositions.
In some western modern or experimental forms, the written notation of art music may depart from standard musical notation and use a variety of new types of notation to facilitate the exploratory nature of these new forms of music. The inclusion of the new forms within the definition of "art music" is based upon the intention of the composer for the experience created by the music and upon the method of the composer in communicating the substance of the music to the performer. In other words, while the notation may not be formal or traditional, there remains an element of formality or intellectual discipline to the construction and communication of the content of the work.