Attributes

An attribute defines some quality of how an instrument (or multiple instruments) plays its notes.

Under the hood, attributes are implemented as inline clojure code.

Setting the Value of an Attribute

Just like setting octaves, setting an attribute will take effect for all of an instrument's upcoming notes, until that attribute is changed again. (In fact, octave is also a settable attribute.)

Different attributes take different kinds of values. A lot of the time, the value is a number between 0 and 100, but this is not always the case.

Examples

(volume 50)

(quant 85)

(octave :up)

(tempo 240)

(key-signature "f+ c+ g+")

See below for more information about the different kinds of attributes that are available to you when writing a score.

Getting the Current Value of an Attribute

To obtain the current value of an attribute for the current instrument(s), prefix the name of the attribute with a dollar sign ($).

You typically will not need to do this when writing a score, but it may be helpful when writing an Alda score via alda.lisp, or when doing complicated things with inline Clojure code.

As a simple example, this will print the current value of the volume of the piano instance:

piano:
  (println ($volume))
  c d e f g

Caveat: When using this syntax in a part with multiple instruments (e.g. piano/trumpet: (prn ($volume))), only one of the instruments' values will be returned. Tread with caution!

Per-Instrument vs. Global

By default, an attribute change event is only applied to the instrument(s) that you're currently working with. For instance, in a score with four instruments:

violin "violin-1": 
  o4 f2   g4 a   b-2   a

violin "violin-2": 
  o4 c2   e4 f   f2    f

viola: 
  o3 a2 > c4 c   d2    c

cello: 
  o3 f2   c4 f < b-2 > f

Changing an attribute will only affect the instrument(s) whose part you are currently editing:

violin "violin-1": 
  o4 f2   g4 a   b-2   a

violin "violin-2": 
  o4 c2   e4 f   f2    f

viola: 
  o3 a2 > c4 c   d2    c

cello: 
  (volume 75)
  o3 f2   c4 f < b-2 > f

To change an attribute globally (i.e. for every instrument in the score), add an exclamation mark (!) after the name of the attribute:

violin "violin-1": 
  (tempo! 80)
  o4 f2   g4 a   b-2   a

violin "violin-2": 
  o4 c2   e4 f   f2    f

viola: 
  o3 a2 > c4 c   d2    c

cello: 
  o3 f2   c4 f < b-2 > f

Attributes can also be set globally at the beginning of a score, before you start writing out any instrument parts. The attributes will still be set for every instrument.

(tempo! 80)

violin "violin-1": 
  o4 f2   g4 a   b-2   a

violin "violin-2": 
  o4 c2   e4 f   f2    f

viola: 
  o3 a2 > c4 c   d2    c

cello: 
  o3 f2   c4 f < b-2 > f

List of Attributes

`duration`

Abbreviations: (none)
Description: The length that a note will have, if not specified. For example, c4 is explicitly a quarter note; c will have a note-length equal to the value of the instrument's duration attribute. (Note that this attribute is more of an implementation detail, as it is called implicitly whenever you specify a note-length for a note. You will probably never need to use this attribute directly.)
Value: a number of beats (e.g. 2.5, which represents a dotted half note).
Initial Value: 1 (i.e. a quarter note)

`key-signature`

Abbreviations: key-sig
Description: a set of sharp or flat symbols to be applied to certain notes by default when the note doesn't include accidentals. For example, if the key signature contains G-sharp, then a note g will become G-sharp by default, unless an accidental is placed after the note, i.e. g- (G-flat) or g (G natural).
Value: either:
a map of letters (as keywords) to lists of accidentals for that letter, e.g. {:f [:sharp] :c [:sharp] :g [:sharp]},
a string like "f+ c+ g+", or
a vector like [:a :major] or [:e :flat :minor]
Initial Value: {} (an empty map, signifying no flats/sharps will be applied for any letter)

`octave`

Abbreviations: (none)
Description: The octave of a note. (Note that Alda also has built-in syntax for setting specific octaves, e.g. o5, and moving up > or down < octaves.)
Value: either a number representing an octave in scientific pitch notation, or the keyword :up or :down to move up or down by one from the current octave.
Initial Value: 4

`panning`

Abbreviations: pan
Description: How far left/right the note is panned in your speakers.
Value: a number from 0-100 representing the panning from hard left (0) to hard right (100). 50 is center.
Initial Value: 50

`quantization`

Abbreviations: quant, quantize
Description: The percentage of a note's full duration that is heard. Setting lower quantization values translates into putting more space between notes, making them sound more staccato, whereas setting higher values translates into putting less space between notes, making them sound more legato.
Value: a number between 0 and 100
Initial Value: 90

`tempo`

Abbreviations: (none)
Description: How fast or slow notes are played. This value is used in combination with the length of a note to determine how long to play it in milliseconds.
Value: a number representing a tempo in beats per minute (BPM)
Initial Value: 120

`track-volume`

Abbreviations: track-vol
Description: The overall volume of an instrument. For MIDI instruments, this corresponds to track volume, as opposed to velocity. Typically, you would set track-volume once (if at all) at the beginning of the score, and then use volume for finer-grained control over volume between notes. (When in doubt, just use volume!)
Value: a number between 0 and 100
Initial Value: 78.7 (this number comes from 100/127, which is the default track volume for MIDI, at least on the JVM)

`volume`

Abbreviations: vol
Description: How loud or soft a note is. For MIDI instruments, this corresponds to the velocity of each note, which has to do with not only how loud the note is, but also how strongly the note is played. The details of this vary from instrument to instrument; often, it has an effect on the sharpness of the attack at the beginning of the note.
Value: a number between 0 and 100
Initial Value: 100