sc/cm [ Modules ]
NAME
cm File: cm.lsp Class Hierarchy: none (no classes defined) Version: 1.0.12 Project: slippery chicken (algorithmic composition) Purpose: Definition of common-music related and other functions like transposition of notes/chords, enharmonic equivalents etc. Author: Michael Edwards: m@michael-edwards.org Creation date: 1st March 2001 $$ Last modified: 10:19:05 Sat Jun 18 2022 CEST SVN ID: $Id$
cm/degree-to-note [ Functions ]
DESCRIPTION
Get the specified scale degree number as a note-name pitch symbol within the current scale. An optional argument allows the user to specify that the scale degree number should be used to get the note-name pitch from a different scale.
ARGUMENTS
An integer that is a scale degree number.
OPTIONAL ARGUMENTS
- The scale from which the note-name pitch symbol associated with the specified scale degree is to be drawn.
RETURN VALUE
A note-name pitch symbol.
EXAMPLE
(degree-to-note 127 'chromatic-scale) => G9 (degree-to-note 127 'twelfth-tone) => ATS0 (degree-to-note 127 'quarter-tone) => EQF4
SYNOPSIS
(defun degree-to-note (degree &optional (scale cm::*scale*))
cm/degrees-per-octave [ Functions ]
DESCRIPTION
Return the number of scale degrees in the span of one octave within the current tuning system.
ARGUMENTS
- No arguments.
RETURN VALUE
- An integer that is the number of scale degrees in each octave.
EXAMPLE
(in-scale :chromatic) (degrees-per-octave) => 12 (in-scale :quarter-tone) (degrees-per-octave) => 24
SYNOPSIS
(defun degrees-per-octave (&optional (scale cm::*scale*))
cm/degrees-per-semitone [ Functions ]
DESCRIPTION
Get the number of scale degrees per equal-tempered semitone in the current tuning scale.
ARGUMENTS
- No arguments
OPTIONAL ARGUMENTS
- The scale for which the number of degrees per semitone is to be retrieved.
RETURN VALUE
An integer.
EXAMPLE
(degrees-per-semitone 'chromatic-scale) => 1 (degrees-per-semitone 'twelfth-tone) => 6 (degrees-per-semitone 'quarter-tone) => 2
SYNOPSIS
(defun degrees-per-semitone (&optional (scale cm::*scale*))
cm/degrees-to-notes [ Functions ]
DESCRIPTION
NB: If the specified scale-degree number within the current scale would result in pitch outside of the maximum MIDI pitch range for that tuning (chromatic: C-1 to B10; quarter-tone: C-1 to BQS10; twelfth-tone: C-1 to CTF11), the function will return an error.
ARGUMENTS
An integer that is a scale degree number in the current tuning.
RETURN VALUE
A list of note-name pitch symbols.
EXAMPLE
(in-scale :chromatic) (degrees-to-notes '(0 143 116 127 38)) => (C-1 B10 AF8 G9 D2) (in-scale :twelfth-tone) (degrees-to-notes '(0 144 116 127 38 287 863)) => (C-1 C1 GSS0 ATS0 FSSS-1 CTF3 CTF11) (in-scale :quarter-tone) (degrees-to-notes '(0 144 116 127 38 287)) => (C-1 C5 BF3 EQF4 G0 BQS10)
SYNOPSIS
(defun degrees-to-notes (degrees)
cm/event-list-to-midi-file [ Functions ]
DESCRIPTION
Write the events in a list to a midi-file. events-update-time is a related function useful for preparind ad-hoc events for midi-file-writing.
ARGUMENTS
- A list of events objects - the path to the midi-file - the starting tempo (integer: BPM) - a time-offset for the events (seconds)
OPTIONAL ARGUMENTS
- whether to overwrite events' amplitude slots and use a single velocity/amplitude value given here (0-1.0 (float) or 0-127 (integer)
RETURN VALUE
The MIDI file path
SYNOPSIS
(defun event-list-to-midi-file (event-list &key (midi-file "/tmp/tmp.mid") (start-tempo 120) (time-offset 0) (auto-open (get-sc-config 'midi-play-auto-open)) force-velocity)
cm/freq-to-degree [ Functions ]
DESCRIPTION
Get the scale degree of the specified frequency in Hertz within the current scale. NB: This method will return fractional scale degrees.
ARGUMENTS
A frequency in Hertz.
OPTIONAL ARGUMENTS
- The scale in which to find the corresponding scale degree.
RETURN VALUE
A scale degree number. This may be a decimal number.
EXAMPLE
(freq-to-degree 423 'chromatic-scale) => 68.317856 (freq-to-degree 423 'twelfth-tone) => 409.9071 (freq-to-degree 423 'quarter-tone) => 136.63571
SYNOPSIS
(defun freq-to-degree (freq &optional (scale cm::*scale*))
cm/freq-to-midi [ Functions ]
DATE
10th July 2016, Essen Werden
DESCRIPTION
convert a frequency in Hertz to a MIDI note number (possibly floating point, indicating microtonality).
ARGUMENTS
a frequency in Hertz
RETURN VALUE
a floating point value representing the MIDI note number of the given frequency
EXAMPLE
(freq-to-midi 260) --> 59.892094 (freq-to-midi (midi-to-freq 60)) --> 60.0
SYNOPSIS
(defun freq-to-midi (freq)
cm/freq-to-note [ Functions ]
DESCRIPTION
Get the note-name pitch equivalent of the specified frequency, rounded to the nearest scale degree of the current scale.
ARGUMENTS
A number that is a frequency in Hertz.
OPTIONAL ARGUMENTS
- The scale in which the note-name pitch equivalent is to be sought (Common Music scale object or symbol). If a symbol, then 'chromatic-scale, 'twelfth-tone, or 'quarter-tone only at present.
RETURN VALUE
A note-name pitch symbol.
EXAMPLE
(freq-to-note 423 'chromatic-scale) => AF4 (freq-to-note 423 'twelfth-tone) => GSSS4 (freq-to-note 423 'quarter-tone) => AQF4
SYNOPSIS
(defun freq-to-note (freq &optional (scale cm::*scale*))
cm/get-pitch-bend [ Functions ]
DESCRIPTION
Get the MIDI pitch-bend value necessary for application to a MIDI pitch in order to achieve the specified frequency. NB: This will always return a positive value between 0.0 and 1.0, as slippery-chicken always applies pitch-bends upwards from the nearest chromatic note below the specified frequency. NB: This value will be the same in all tuning scales.
ARGUMENTS
A frequency in Hertz.
RETURN VALUE
A two-digit decimal number that is the pitch-bend value required to achieve the specified frequency in MIDI.
EXAMPLE
(get-pitch-bend 423) => 0.32
SYNOPSIS
(defun get-pitch-bend (freq)
cm/in-scale [ Functions ]
DESCRIPTION
Set the global scale (tuning) for the current slippery-chicken environment. Current options are :chromatic, :quarter-tone or :twelfth-tone. See the file cm-load.lsp for specifications and the html manual page "More about note-names and scales" for more details on use.
ARGUMENTS
- A scale (tuning) designation.
RETURN VALUE
the (new) Common Music scale object
EXAMPLE
(in-scale :chromatic) => #<tuning "chromatic-scale"> (in-scale :quarter-tone) => #<tuning "quarter-tone"> (in-scale :twelfth-tone) => #<tuning "twelfth-tone">
SYNOPSIS
(defun in-scale (scale)
cm/midi-file-to-events [ Functions ]
DATE
28/6/16, Edinburgh
DESCRIPTION
Read in a MIDI file and convert notes to event objects. NB This won't (yet) import microtones as indicated by pitch-bend messages
ARGUMENTS
the path to the midi file
OPTIONAL ARGUMENTS
keyword arguments: - :track. The track number to read. Default = NIL which means read all tracks. - :tempo. The tempo of the track in crotchets (quarter notes) per minute. Default, q = 120.
RETURN VALUE
a list of event objects
SYNOPSIS
(defun midi-file-to-events (file &key track (tempo 120.0))
cm/midi-to-degree [ Functions ]
DESCRIPTION
Convert the specified MIDI note number to the degree number of the current scale.
ARGUMENTS
- A MIDI note number.
RETURN VALUE
- An integer that is the scale-degree equivalent of the specified MIDI note number in the current scale.
EXAMPLE
(in-scale :chromatic) (midi-to-degree 64) => 64 (in-scale :twelfth-tone) (midi-to-degree 64) => 384 (in-scale :quarter-tone) (midi-to-degree 64) => 128
SYNOPSIS
(defun midi-to-degree (midi-note &optional (scale cm::*scale*))
cm/midi-to-freq [ Functions ]
DESCRIPTION
Get the frequency equivalent in Hertz to the specified MIDI note number.
ARGUMENTS
- A number (can be a decimal) that is a MIDI note number.
RETURN VALUE
A decimal number that is a frequency in Hertz.
EXAMPLE
(midi-to-freq 67) => 391.99542 (midi-to-freq 67.9) => 412.91272
SYNOPSIS
(defun midi-to-freq (midi-note)
cm/midi-to-note [ Functions ]
DESCRIPTION
Get the note-name pitch symbol equivalent of the specified MIDI note number.
ARGUMENTS
- a MIDI note number: integer or float. If float, appropriate microtones will be returned if the current scale is microtonal (e.g. (in-scale :quarter-tone))
RETURN VALUE
A note-name pitch symbol.
EXAMPLE
(midi-to-note 67) => G4 (midi-to-note 60.5) =>CQS4
SYNOPSIS
(defun midi-to-note (midi-note &optional (scale cm::*scale*))
cm/midi2qlist [ Functions ]
DATE
10th November 2016, Edinburgh
DESCRIPTION
Convert a midi-file to qlist text format, for sequencing in PD or MaxMSP. If you don't want specific tracks from the file, just pass two arguments so <tracks> remains nil.
ARGUMENTS
- the path to the midi file you want to convert (string) - the path to the qlist text file you'd like to write (string). If this is nil then we'll write to the same patch as the midi file with the extension .txt added. NB If this file exists it will be overwritten, no questions asked. - (&rest) the numbers of the tracks you'd like to convert, starting from 1.
RETURN VALUE
The number of notes written (integer)
SYNOPSIS
(defun midi2qlist (midi-file qlist-file &rest tracks)
cm/note-to-degree [ Functions ]
DESCRIPTION
Get the scale degree number of the specified note-name pitch symbol within the current scale.
ARGUMENTS
- A note-name pitch symbol.
OPTIONAL ARGUMENTS
- The scale in which to find the scale-degree of the specified pitch.
RETURN VALUE
An integer that is a scale degree in the current scale.
EXAMPLE
(note-to-degree 'AF4 'chromatic-scale) => 68 (note-to-degree 'AF4 'twelfth-tone) => 408 (note-to-degree 'AF4 'quarter-tone) => 136
SYNOPSIS
(defun note-to-degree (note &optional (scale cm::*scale*))
cm/note-to-freq [ Functions ]
DESCRIPTION
Get the frequency in Hertz of the specified note-name pitch symbol.
ARGUMENTS
- A note-name pitch symbol.
RETURN VALUE
A frequency in Hertz.
EXAMPLE
(in-scale :chromatic) (note-to-freq 'AF4) => 415.3047 (in-scale :twelfth-tone) (note-to-freq 'GSSS4) => 423.37845 (in-scale :quarter-tone) (note-to-freq 'AQF4) => 427.47403
SYNOPSIS
(defun note-to-freq (note)
cm/note-to-midi [ Functions ]
DESCRIPTION
Get the MIDI note number equivalent for a chromatic note-name pitch symbol.
ARGUMENTS
- A chromatic note-name pitch symbol.
RETURN VALUE
An integer.
EXAMPLE
(note-to-midi 'g4) => 67
SYNOPSIS
(defun note-to-midi (midi-note)
cm/set-diapason [ Functions ]
DATE
March 11th 2021
DESCRIPTION
Set the frequency of the note A4 (the diapason). By default, in slippery chicken (and common music) this is 440 Hertz. If this function is called, it will change the diapason for all currently defined scales, and thus will affect all calculations in any scale that converts to or from frequency. NB Explicit calling of this function is discouraged. Use instead something like this: (set-sc-config 'diapason 442)
ARGUMENTS
- the new frequency of the note A4 (middle A: i.e. the note played by the oboe when a western orchestra tunes). (For internal use, if this is NIL, the frequency of the lowest A will be returned.)
RETURN VALUE
The frequency in Hertz of the lowest A in the (new) tuning.
EXAMPLE
SYNOPSIS
(let ((low-a 440/64)) ; 6.875Hz (lowest A) (defun set-diapason (hertz)