freq — frequency representation


The freq representation can be used to represent frequencies for pure or complex tones. freq distinguishes three types of tokens: frequencies, rests, and barlines. Frequencies are encoded in hertz (Hz) where 440 Hz means 440 cycles per second. Frequencies may be specified as integer or real values (using a decimal). In addition, freq provides limited capabilities for representing phrasing and slurs.

Barlines are represented using the "common system" for barlines — see barlines.


It is recommended that files containing predominantly freq data should be given names with the distinguishing `"' extension.


The following table summarizes the freq mappings of signifiers and signifieds.

0-9 frequency (in hertz) specified as an integer or real value r rest = barline; == double barline ( slur start ) slur end { phrase mark (start) } phrase mark (end) ; pause sign —– ———————————————-

Summary of freq Signifiers


A sample document is given below:


**freq **freq *pure *complex =1 =1 440 (440 440.9 . 880 440

  1. . . 440) =2 =2 r r == == *- *- ———- ———–

Notice that frequencies can be either real or integer values. Rests are represented by the single letter `r'.


The following Humdrum commands accept freq encoded data as inputs:

barks translates freq to barks cbr translates freq to cbr cents translates freq to cents cocho translates freq to cocho kern translates freq to kern pc translates freq to pc pitch translates freq to pitch semits translate freq to numerical semits solfg translate freq to numerical solfg specc translate freq to numerical specC tonh translate freq to numerical Tonh vox determine active and inactive voices in a Humdrum file

The following Humdrum command produces freq data as output:

freq translates cbr, cents, cocho, freq, fret, kern, MIDI, pitch, semits, solfg, specC, and Tonh to cents – ———————————– ————————————————————————————————————————————————————————————————————–


The following tandem interpretations can be used in conjunction with freq:

pure tones *pure complex tones *complex meter signatures *M6/8 key signatures *k[f#c#] key *c#: —————— ————

Tandem interpretations for freq


barlines, **cbr, **cents, **coch, **degree, **kern, **pc, **pitch, **semits, **specC, **Tonh