Humdrum Toolkit Command Reference -- freq

COMMAND

freq -- translate selected Humdrum pitch-related representations to frequency

SYNOPSIS


freq  [-p n]  [-tx]  [inputfile ...]  [> outputfile"]

DESCRIPTION

The freq command transforms various pitch-related inputs to corresponding frequency representations. It outputs one or more Humdrum **freq spines containing numerical values (in hertz) corresponding to the fundamental frequency for pitch-related input tokens. For example, the **pitch token "C4" is transformed to 261.63 (hertz).

The freq command is able to translate any of the pitch-related representations listed below. In each case, a tuning standard of A4 equals 440 hertz is assumed. For descriptions of the various input representations (including **freq) refer to Section 2 (Representation Reference) of this reference manual.

It is recommended that output files produced using the freq command should be given names with the distinguishing `"' extension.

**cbr critical band rate (in equivalent rectangular bandwidth units)

**cents hundredths of a semitone with respect to middle C=0 (e.g. 1200 equals C5)

**cocho cochlear coordinates (in millimeters)

**freq fundamental frequency (in hertz)

**fret fretted-instrument pitch tablature

**kern core pitch/duration representation

**MIDI Music Instrument Digital Interface tablature

**pitch American National Standards Institute pitch notation (e.g. "A#4")

**semits equal-tempered semitones with respect to middle C=0 (e.g. -12 equals C3)

**solfg French solfège system (fixed `doh')

**specC spectral centroid (in hertz)

**Tonh German pitch system

Input representations processed by freq.

OPTIONS

The freq command provides the following options:

-h displays a help screen summarizing the command syntax

-p n output precision of n decimal places

-t suppresses printing of all but the first note of a group of tied **kern notes

-x suppresses printing of non-frequency signifiers

Options are specified in the command line.

The -p option can be used to set the precision of the output values to n decimal places. The default precision is two decimal places. Note that freq is able to process **freq as input; this feature allows the user to round-off existing **freq data to a specified precision.

The -t option ensures that only a single output value is given for tied **kern notes; the output coincides with the first note of the tie.

In the default operation, freq outputs non-pitch-related signifiers in addition to the frequency value. For example, the **pitch token "A6zzz" will result in the output "1760.00zzz" -- that is, after translating A6 to 1760.00 hertz, the "zzz" signifiers are retained in the output. For some applications, echoing non-pitch-related signifiers in the output is useful. However, in other situations, the result can prove confusing -- especially, when the non-pitch-related signifiers are numbers. Consider the case of the **kern token "8aaa"; after translating `aaa' to 1760.00 hertz, the non-pitch-related signifier `8' will also be output, hence the value 81760.00 -- which will undoubtedly cause confusion. The -x option is useful for eliminating non-pitch-related signifiers from the output. For most **kern inputs, the -x option is recommended.

EXAMPLES

The following example illustrates the use of freq. The input contains six pitch-related spines -- one of which (**deg) cannot be processed by freq. In addition, there are two non-pitch-related spines (**embell and **metpos).



!! `freq' example.
**kern **pitch **MIDI **deg **metpos **cocho **Tonh **embell
*M2/4 *M2/4 *M2/4 *M2/4 *M2/4 *M2/4 *M2/4 *M2/4
* * * * *tb8 * * *
=1 =1 =1 =1 =1 =1 =1 =1
8ee- G#4foo /60/bar 1foo 1 r Gis2 ct
. . /-60/ . . . . .
8ff A3 /62/ 2 3 9.89 H2 upt
. . /-62/ . . . . .
8dd- Ab3 /70/ 1 2 7.07 B2 ct
. . /-70/ . . . . .
8d- C#4 /61/ 6 3 7.135 Cis4 sus
. . /-61/ . . . . .
=2 =2 =2 =2 =2 =2 =2 =2
[4a- r . 5 1 r r .
. . . 7 3 5.5 Heses2 ct
4a-] D4 /48/ /52/ 1 2 8.11 C3 ct
. . /-48/ . . . . .
. D4 F4 /-52/ 2 3 7.33 6.4 C3 Es3 ct
=3 =3 =3 =3 =3 =3 =3 =3
r G4 . r 1 r H2 D3 .
=== === === === === === === ===
*- *- *- *- *- *- *- *-

Executing the command

freq -tx input > output"

produces the following result:

!! `freq' example.

**freq **freq **freq **deg **metpos **freq **freq **embell

*M2/4 *M2/4 *M2/4 *M2/4 *M2/4 *M2/4 *M2/4 *M2/4

* * * * *tb8 * * *

=1 =1 =1 =1 =1 =1 =1 =1

622.25 415.30 261.63 1foo 1 r 103.83 ct

. . . . . . . .

698.46 220.00 293.66 2 3 481.97 123.47 upt

. . . . . . . .

554.37 207.65 466.16 1 2 273.21 116.54 ct

. . . . . . . .

277.18 277.18 277.18 6 3 277.16 277.18 sus

. . . . . . . .

=2 =2 =2 =2 =2 =2 =2 =2

415.30 r . 5 1 r r .

. . . 7 3 187.76 110.00 ct

. 293.66 130.81 164.81 1 2 340.92 130.81 ct

. . . . . . . .

. 293.66 349.23 . 2 3 289.24 234.47 130.81 155.56 ct

=3 =3 =3 =3 =3 =3 =3 =3

r 392.00 . r 1 r 123.47 146.83 .

=== === === === === === === ===

*- *- *- *- *- *- *- *-

Both processed and unprocessed spines are output. Notice that the tied note at the beginning of measure 2 in the **kern spine has been rendered as a single note rather than as two notes (due to the -t option). Also notice that the non-pitch-related signifiers (e.g. foo) in the first notes of the **pitch, **MIDI, and **cocho spines have been stripped away (due to the -x option).

FILES

The file x_option.awk is used by this program when the -x option is invoked.

PORTABILITY

DOS 2.0 and up, with the MKS Toolkit. OS/2 with the MKS Toolkit. UNIX systems supporting the Korn shell or Bourne shell command interpreters, and revised awk (1985).

`**cbr`	critical band rate (in equivalent rectangular bandwidth units)
`**cents`	hundredths of a semitone with respect to middle C=0 (e.g. 1200 equals C5)
`**cocho`	cochlear coordinates (in millimeters)
`**freq`	fundamental frequency (in hertz)
`**fret`	fretted-instrument pitch tablature
`**kern`	core pitch/duration representation
`**MIDI`	Music Instrument Digital Interface tablature
`**pitch`	American National Standards Institute pitch notation (e.g. "A#4")
`**semits`	equal-tempered semitones with respect to middle C=0 (e.g. -12 equals C3)
`**solfg`	French solfège system (fixed `doh')
`**specC`	spectral centroid (in hertz)
`**Tonh`	German pitch system

-h	displays a help screen summarizing the command syntax
-p n	output precision of n decimal places
-t	suppresses printing of all but the first note of a group of tied `**kern notes`
-x	suppresses printing of non-frequency signifiers

!! `freq' example.
**kern	**pitch	**MIDI	**deg	**metpos	**cocho	**Tonh	**embell
*M2/4	*M2/4	*M2/4	*M2/4	*M2/4	*M2/4	*M2/4	*M2/4
*	*	*	*	*tb8	*	*	*
=1	=1	=1	=1	=1	=1	=1	=1
8ee-	G#4foo	/60/bar	1foo	1	r	Gis2	ct
.	.	/-60/	.	.	.	.	.
8ff	A3	/62/	2	3	9.89	H2	upt
.	.	/-62/	.	.	.	.	.
8dd-	Ab3	/70/	1	2	7.07	B2	ct
.	.	/-70/	.	.	.	.	.
8d-	C#4	/61/	6	3	7.135	Cis4	sus
.	.	/-61/	.	.	.	.	.
=2	=2	=2	=2	=2	=2	=2	=2
[4a-	r	.	5	1	r	r	.
.	.	.	7	3	5.5	Heses2	ct
4a-]	D4	/48/ /52/	1	2	8.11	C3	ct
.	.	/-48/	.	.	.	.	.
.	D4 F4	/-52/	2	3	7.33 6.4	C3 Es3	ct
=3	=3	=3	=3	=3	=3	=3	=3
r	G4	.	r	1	r	H2 D3	.
===	===	===	===	===	===	===	===
*-	*-	*-	*-	*-	*-	*-	*-

!! `freq' example.
**freq	**freq	**freq	**deg	**metpos	**freq	**freq	**embell
*M2/4	*M2/4	*M2/4	*M2/4	*M2/4	*M2/4	*M2/4	*M2/4
*	*	*	*	*tb8	*	*	*
=1	=1	=1	=1	=1	=1	=1	=1
622.25	415.30	261.63	1foo	1	r	103.83	ct
.	.	.	.	.	.	.	.
698.46	220.00	293.66	2	3	481.97	123.47	upt
.	.	.	.	.	.	.	.
554.37	207.65	466.16	1	2	273.21	116.54	ct
.	.	.	.	.	.	.	.
277.18	277.18	277.18	6	3	277.16	277.18	sus
.	.	.	.	.	.	.	.
=2	=2	=2	=2	=2	=2	=2	=2
415.30	r	.	5	1	r	r	.
.	.	.	7	3	187.76	110.00	ct
.	293.66	130.81 164.81	1	2	340.92	130.81	ct
.	.	.	.	.	.	.	.
.	293.66 349.23	.	2	3	289.24 234.47	130.81 155.56	ct
=3	=3	=3	=3	=3	=3	=3	=3
r	392.00	.	r	1	r	123.47 146.83	.
===	===	===	===	===	===	===	===
*-	*-	*-	*-	*-	*-	*-	*-