Scale design software
A scale design software application, or a scale designer, is a suite of tools for exploring the properties of scales and sometimes also tuning systems, for creating entirely new scales and tunings, and for semi-guided scale and tuning development based on principles discovered by theorists. The tools provided by a scale designer may include tables showing the scale's pitches in decimal cents, ratios and named interval formats; interval analysis; circular or other graphical mappings; scale or tuning transformations; comparisons between alternatives; and many more.
Scala is one of the most popular, long-standing, and powerful scale and tuning development environments and worth exploring. However, its learning curve is steep and its text-based roots make it less enjoyable to use for some people. More recently developed scale designers are centered on graphical tools that clearly show relationships between scale notes. They are frequently built into tuning plugins, so your preferred scale design software may just be the one that fits your preferred retuning workflow. Other scale designers are standalone desktop applications like Scala, browser-based applications like Scale Workshop, or built into a virtual instrument (e.g. Surge XT).
Scale designers and tuning editors
It's important to realize that the words "scale" and "tuning" have different meanings in different contexts. In the context of scale design software (aka scale designers), tuning editors, and tuning systems, scales can be understood abstractly as an ordered set of notes, whose roughly demarcated structure of intervals is determined by cultural music traditions or based on one of many possible patterns. In this same context, tuning systems can be understood as mathematical specifications for the set of exact pitch frequencies upon which those scale notes are to be be positioned. Tuning systems can define a large number of possible pitch locations, and a scale may include all or only a subset of them. A broader meaning of the term "tuning system" can encompass both scale and tuning, but splitting these is useful for understanding scale design software.
For example, the 12edo tuning system offers 12 possible frequencies per period for placing notes upon, all of which are used by the 12edo Chromatic scale, but only some of which are used by the 12edo Major scale. These examples also highlight that an unambiguous, concrete scale description must name the tuning system being used. The "12edo Major" scale and "Ptolemy's intense diatonic Major" scale are both Major scales. They are both diatonic — i.e. have five large (L) and two maximally separated small (s) intervals per period — and follow the Major mode's intervallic pattern (L L s L L L s). But they place all their notes besides the tonic on slightly different pitch frequencies, because they follow two different tuning systems — a just intonation in the Ptolemy case and an equal temperament in the 12edo case.
Therefore, we could define a scale designer as a software tool for indicating the notes of a scale and their exact pitch frequencies. Given that definition, a tuning editor might could be understood as a more general tool for exploring the various mathematical patterns from which tuning systems are developed. However, you will encounter software that uses these terms differently, as well as many other names that point toward these same functions being fulfilled. And software in this category frequently combines at least some of the functions of a scale designer and tuning editor. Just keep in mind that apart from the abstract meanings of the terms scale and tuning, to play music you will ultimately need to indicate both the notes of your scale and the exact frequencies on which they are placed.
Glossary for scale design software
Some of the terms discussed below appear in various forms in all music software, while others are specific for tuning software and electronic instruments. However, when establishing tuning for tonical (aka tonal) music set in non-12edo tunings it can be critically important to recognize the concepts behind each of these terms, and not take for granted that a software or electronic musical instrument will properly set these properties or even recognize the need to do so. The distinction between tuning base and reference note is especially important outside equal temperament tunings.
In brief, a tuning base anchors the scale, maps it to a MIDI note number, and may be the note from which an intervallic network is established, all without necessarily specifying any reference pitch frequency. In contrast, a reference note is used to set the specific pitch frequency of one of the notes in the scale, from which the pitch of the others is implied by the intervallic network. The tuning base note may or may not be set the same as the reference note.
Tuning base
The implied note, or explicit MIDI note number, on which the tuning file's scale is anchored. In the part of a tuning file that specifies a scale, it is usually the first, usually lowest pitched, scale note defined in a tuning file. In some tuning file systems, the other notes in the scale may be defined with reference to the tuning base (e.g. by frequency ratio or distance in cents). In the part of a tuning file that specifies a keyboard mapping, the tuning base is the MIDI note to which the scale is anchored.
Also called the tuning base note, tuning base MIDI note (in a MIDI context), scale base, base note (too easily confused with bass note), 1/1 (referring to its intervallic relationship with itself), or the "middle note" which (unfortunately) is how it's named in the Scala keyboard mapping file (.kbm) specification.
A brief aside in support of clarity... It can be misleading to refer to the tuning base as the a tonic, root, or key, although this is sometime done when they point to the same note. The conceptual tool that is a tuning base does not directly appear in Western classical music theory. It's related to the concepts of tonic and key, but the tuning base is just a technical tool that operates in the context of needing to map a scale onto a musical instrument controller like a MIDI keyboard. Not every tuning base is also a tonic or key (e.g. in atonal music), and "root" applies most correctly to chords but not scales. Although the lowest note in a scale (i.e. a pitch set usually ordered by pitch frequency), is typically called the scale's tonic in common musicology terms, it does not have tonical function in atonal music, so "base" is a more general term though not in common use.
Reference note
The named note, or the MIDI note number, of the reference pitch. Also called the tuning center (e.g. in piano tuning terminology), or in a MIDI context the reference MIDI note.
The reference note can also be used as the tuning base note. For simplicity, it is common to use C4 as both tuning base and reference note for EDO scales, with a reference pitch of 261.63 Hz. However, in the case of tonical music using a non-EDO scale (e.g. set to just intonation or meantone tuning systems) carefully setting the tuning base is critical because the uneven intervals require placing the tuning base on the tonic note of the music. Otherwise, the tuning will be off.
But the reference note used for the reference pitch can still be any note of the scale. A4 is commonly used as a reference note because 440 Hz exactly is the ISO-16-1975 tuning reference standard pitch for A4 on a piano keyboard, so no frequency approximation is required. An alternative approach for non-EDO tonical music is to set both the tuning base and reference note to the music's tonic, and set the reference pitch to what the reference note's pitch frequency would have been in a standard 12edo concert pitch system.
Reference pitch
The exact pitch frequency (typically in Hz) for the reference note. Based on that pitch frequency, all other notes in the scale or tuning system will be assigned a frequency, according to their intervallic relationship to the reference note. Also called the pitch reference, or tuning center, and sometimes the concert pitch (for an ensemble).
The reference note and pitch are sometimes casually specified with a combination named note, MIDI number, and pitch frequency expression, e.g. A4-440Hz-MIDI.69, meaning 440 Hz exactly for the A above middle C, because A4=440Hz is the international standard. For cases other than A4=440Hz, in a tuning specifier like C4-261Hz-MIDI.60 for example, the "261" is typically an approximation. It implies a more accurate number should be specified in the tuning file itself, with 2-4 digits after a decimal point (e.g. 261.6256).
Keyboard mapping
A data set that specifies how the notes of the scale are to be mapped to the MIDI notes of a musical instrument controller (e.g. a keyboard), beyond just the tuning base and reference note. For example, a seven note per octave scale might be mapped to skip the black keys on a standard piano keyboard layout. Or a scale with more than 12 notes per octave might be mapped in a way that uses only a subset of the scale, or makes the octaves easier to recognize within the black/white key pattern.
Linear keyboard mapping
A mapping between scale and keyboard controller keys, in which the notes of the scale are simply applied in a sequential order starting from the tuning base. In the absence of an explicit keyboard mapping, music software will typically assign linear keyboard mapping. In this case the pattern of black and white keys on a standard piano keyboard might not align with meaningful intervals of the scale.
List of scale design software
A few currently popular or notable scale designers are listed below. Most are embedded in software that also performs other functions. You'll find more complete and up-to-date lists in the Tuning manipulation software section of the "List of music software" page, and the Tuner plugins section of the "List of microtonal software plugins" page. Note that not all tuner plugins include a well-developed scale designer.
- Scala, from Manuel Op de Coul (standalone desktop application)
- Scale Workshop, from Lumi Pakkanen and Sevish (browser-based application)
- Entonal Studio, by Entonal (tuner plugin)
- MTS-ESP Suite and MTS-ESP Mini, by ODDsound (tuner plugin)
- Infinitone DMT, by Infinitone (tuner plugin)
- Surge XT, by the Surge Synth Team (software synthesizer)