By simple definition eye music is when the graphic notation of music is altered in some meaningful way visible to the performers. Often the changed "meaning" of the altered notation is enhanced by the music having compositional elements of melody and form such as
word painting and
canon. Moreover, the concept is demonstrated by sometimes differing perceptions of composer, performer, and listener.
Eye music and puzzle-solving The difficulty in definition is also apparent with border-line cryptographic
contrapuntal works such as
puzzle canons, which appear in the score entirely as a bare line of notes with
clefs,
rests,
time signatures,
key signatures or brief cryptic clues in Latin to reveal multiple lines of music in canons of diminution, augmentation, etc. (Closer to true cryptographic works would be those with
soggetto cavato, where letters are embedded in the work using their
solfège names.) The
type of puzzle canon is also a factor. A four-voiced circular canon, when notated as a puzzle canon, may remain an un-worked-out single line of notes, and be inadmissible as eye music. When that single line of notes is inscribed in a graphical shape it becomes eye music, even if the
contrapuntal puzzle remains unsolved. An even finer use of graphical conceit is when the canon does not have any musical way to end, and are in a sense "infinite"—classically referred to as
canon perpetuus, more commonly as "circular canons," and even more commonly as "
rounds." When an infinite (circular) canon is inscribed in a circle, and the
circle itself is a clue that means "play me as a round," a different type of eye music entails.
Eye music for the performer Another class of eye music is when the score is purposely made difficult for the performer. For example, in
Benedetto Marcello's cantata
Stravaganze d’amore, the
continuo part is written entirely in
enharmonic chords, that is, "puns" of chord indications spelled with no regard to the key of the rest of the ensemble, but (in
equal temperament) indistinguishable audibly from those spelled in the appropriate way. Here, the perverse spelling (whether humorous or annoying to the trained continuo player) is not unusual graphically, but represents a score writing unmotivated except as an inside joke between composer and performer, and is unhearable by the listener. The
Gulliver Suite by
Telemann discussed below, shows a combination of three eye music features. The score is made difficult "unnecessarily," is eye-catching for its graphics, and has a clever external reference, all unnoticeable to the listener. ==The Renaissance==