The OMN language provides for a textual equivalent to the many symbols used in traditional staff notation.
In the parameter of LENGTH these symbols represent exact durations of virtual time.
Here are the standard values of note-lengths. The most commonly-used are represented in the OMN language by the first letter of their American arithmetic name, so w is a whole-note, h is a half-note, q is a quarter note and so on.
Here are the standard values of rest-lengths.The most commonly-used are represented in the OMN language by the first letter of their American arithmetic name but with the prefix of a - (minus) sign, so -w is a whole-note rest, -h is a half-note rest, -q is a quarter note rest and so on. To assist with multiple rests -12 will produce 12 bars of whole-note rests.
'(q q q)
Here is a list of three quarter-notes. The list has to begin with a '(a quote) and be enclosed by parentheses ( ).
'(q -e e q)
The example above shows note-lengths and rest-lengths in combination.
Length 8 will produce 8 bars of whole-notes lengths.
'(8 h q q)
Length -8 will produce 8 bars of whole-notes rests.
'(-8 h q q)
Symbol: . .. ...
OMN dots are used the same way as in the standard notation. The maximum dots in OMN length is 3.
The OMN system of rhythmical notation is initially constructed on the principle of duple divisions. Here the individual note-lengths stand for their face value.
w = (h h)
h = (q q)
q = (e e)
and so on.
The other divisional types must make do by borrowing from this binary series:
duplet (2), triplet (3), quadruplet (4), quintuplet (5), sextuplet (6), septuplet (7), octuplet (8), nontuplet (9) etc…
When we write these values we use the same note-values as the immediately preceding binary division.
'((3w 3w 3w) (3h 3h 3h) (3q 3q 3q))
This means for example that a triplet division of the quarter note uses eighth notes.
'((5w = = = =) (5h = = = =) (5q = = = =))
This means for example that a quintuple division of the quarter note uses sixteenth notes.
'((e. s q =) (e. s q =))
The use of repeat symbols for note-lengths and rest-lengths is fundamental to OMN. Its use can give score scripts a very particular style and appearance. Composers will soon discover different approaches will suit particular situations when writing for percussion or in the notation of repetitive textures.
'((q -e = q) (q - e. t =))
If a note-length repeat symbol follows a rest-length a note-length is given.
'(s e - s - e. -s e s -e)
The use of the rest-length repeat can bring clarity to the visual layout of a phrase.
Length composed of two or more separate length elements:
'(qs s e h)
'(hqs -s qe)
Attribute: tie (omn form)
OMN has two types of ties. The first one is a tie length symbol _ and the second one is the attribute tie.
'((h_e e q) (q_3q 3q 3q -h))
The tie symbol is used when a tie is necessary in the middle of a list.
'((h_e c4 e_q tie) (q_3q c4 3q 3q_h))
The tie as an attribute is necessary when a tie goes across one list to join a length symbol in an adjacent list.
'(s == -- = - === - == = --)
Both note-lengths and rest-lengths can be extended simply by bringing the symbols together in the same way pitches come together to produce chords. In percussion writing this can provide further clarity because only one length value needs to be set at the beginning of the list.
'(3q == -e = s - = - == --)
'(s== = = = = =)
'(5q== = = 7q=== = = =)
'(5q== - = 7q=== = - =)
'(s== == -- = - === - == = --)
OMN notation allows the use of ratio values if more convenient.
'((q = e = h) (q - e. t =))
'((1/4 1/4 1/8 1/8 1/2) (1/4 -1/4 3/16 1/32 1/32))
Many functions automatically output ratios as a default rather than OMN symbols. This can usually be changed by setting a keyword within the function such as :omn t.
'((q_e e q) (q -3q = = h))
'((1/4_1/8 1/8 1/4) (1/4 -1/12 1/12 1/12 1/2))
The tie mechanism in both its forms works with ratios.
(M. Ravel, Bolero, 1928)
'((e 3e = = e 3e = = e =) (e 3e = = e 3e = = = = =))
(D. Scarlatti, Sonata B-Dur, 1736)
'((e e5 3e g5 bb4 g4 e a4) (3e a5 c4 a4 e bb4 3e g5 bb4 g4) (s a4 c6 c6 a5 a5 f5) (s f5 d5 d5 c5 d5 bb5))
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