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Consolidate lead section, move Wikipedia links as boxes at the top, add some info about historical/acoustic use of retuning strategies, add table of isomorphic layouts, improve layout column in alternative keyboards column, misc. edits
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Pianos, harpsichords and organs are suited for microtonal music insofar as the strings/pipes can, within limits, be tuned to anything desired.
Pianos, harpsichords and organs are suited for microtonal music insofar as the strings/pipes can, within limits, be tuned to anything desired. The probability that tuning issues arise with these instruments is even slightly higher than average since there is often "old" music (baroque and older, from the pre-well-tempered age) being played on them.


In the case of harpsichords and organs, the probablity that tuning issues arise is even slightly higher than average since there is often "old" music (baroque and older, from the pre-well-tempered age) being played on them.
For electronic instruments (synthesizers), there is, in theory, absolute freedom for the pitches anyway — not in practice, though. But nowadays, many synthesizers have a built-in retuning functionality.


For electronic instruments (synthesizers), there is, in theory, absolute freedom for the pitches anyway - not in practice, though. But nowadays, many synthesizers have a built-in retuning functionality. A broad overview over the microtonal capacities of synthesizers can be found on [http://www.microtonal-synthesis.com www.microtonal-synthesis.com].
A potential source for troubles is the traditional keyboard design, the [[Halberstadt keyboard]], which is optimized for diatonic scales and 12 tones per octave. For microtonal music with not more than 12 tones per octave, this is not such a problem — fingerings for non-standard scales can be learned. But it can become a problem if you need more than 12 tones per octave, or even want a [[nonoctave]] tuning, such as [[Bohlen-Pierce]] or one of [[Wendy Carlos]]'s equal-step scales. Fortunately, there exist several solutions to this problem.
 
A side remark: Synthesizers, even without retuning functionality, often have a special functionality that is principally also suited for microtonality: the modulation wheel. An impressive example of how to make microtonal music with the modulation wheel can be found [http://www.timomusic.ch/video_Spiros_Kottis.htm here]{{dead link}}. This is, however, not a particularly easy way to do it...


== Strategies for more than 12 tones per octave ==
== Strategies for more than 12 tones per octave ==
A potential source for troubles is the traditional keyboard design, which is optimized for diatonic scales and 12 tones per octave.
=== Multiple keyboards ===
 
One solution is to use several keyboards whose keys are slightly detuned against each other. This solution was namely used by several classical composers in the 20th century, including [[Alois Hába]], [[Charles Ives]] and [[Ivan Wyschnegradsky]], usually with a [[12edo]] tuning on each keyboard, but with different reference pitches. [[24edo]] can be achieved by tuning two keyboards a quarter tone apart from each other, [[36edo]] by tuning three keyboards separated by sixth tones, and so on.
For microtonal music with not more than 12 tones per octave, this is not such a problem - fingerings for non-standard scales can be learned. But it becomes a problem if you need more than 12 tones per octave, or even want a non-octave tuning, such as [[Bohlen-Pierce]] or one of [[Wendy Carlos]]'s equal-step scales.
 
There exist several solutions to this problem.
 
=== 12 note Octave Scales ===
(Terminology from [http://www.microtonal-synthesis.com www.microtonal-synthesis.com])
 
Use several keyboards whose keys are slightly detuned against each other.


Advantages are that the keyboard layout keeps the familiar property that 12 key steps span one octave, and the pitches typically need only minor retuning. This is not unimportant for acoustical instruments, where we usually have physical limits to the amount a pitch can be retuned. For this reason, this approach is widely used, especially in the field of contemporary classical music.
Of course, each keyboard's tuning does not have to be 12edo, but choosing a 12-tone octave-repeating scale has its advantages. The keyboard layout keeps the familiar property that 12 key steps span one octave, and the pitches typically need only minor retuning. This is not unimportant for acoustical instruments, where we usually have physical limits to the amount a pitch can be retuned. For this reason, this approach is widely used, especially in the field of contemporary classical music. As for synthesizers, a compatibility list for various models can be found at [http://www.microtonal-synthesis.com Microtonal Synthesis].


The disadvantage is, of course, that you need several keyboards. In the case of acoustic pianos, this means in practice that the maximal number of pitches per octave you can obtain is limited - to the number of pianos you can put on the stage together... [http://www.allmusic.com/composition/arc-en-ciel-for-6-grand-pianos-in-12-tone-tuning-mc0002707751 "Arc-en-ciel" by Ivan Wyschnegradsky], for example, a piece in [[72edo]], is written for six (!) pianos, and [http://www.universaledition.com/Georg-Friedrich-Haas/komponisten-und-werke/komponist/278/werk/13386 "Limited approximations" by Georg Friedrich Haas], in 72edo as well, needs the same number of pianos and moreover a whole orchestra...
The main disadvantage of this solution is, of course, that you need several keyboards. In the case of acoustic pianos, this means in practice that the maximal number of pitches per octave you can obtain is limited - to the number of pianos you can put on the stage together... [http://www.allmusic.com/composition/arc-en-ciel-for-6-grand-pianos-in-12-tone-tuning-mc0002707751 ''Arc-en-ciel''] by [[Ivan Wyschnegradsky]], for example, a piece in [[72edo]], is written for six (!) pianos, and [http://www.universaledition.com/Georg-Friedrich-Haas/komponisten-und-werke/komponist/278/werk/13386 "Limited approximations" by [[Georg Friedrich Haas]], in 72edo as well, needs the same number of pianos and moreover a whole orchestra...


Electronic keyboards sometimes have the possibility to play in "split" mode, i.e. the upper and the lower half of the keyboard can send to different midi channels. Some keyboards offer up to 4 split areas. In this case, you need only one keyboard - but you still have the disadvantage of having to jump between the areas.
Electronic keyboards sometimes have the possibility to play in "split" mode, i.e. the upper and the lower half of the keyboard can send to different midi channels. Some keyboards offer up to 4 split areas. In this case, you need only one keyboard - but you still have the disadvantage of having to jump between the areas.
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* [http://launch.groups.yahoo.com/group/tuning/message/74155 12 note octave scales piano tuning instructions for 41edo]{{dead link}}
* [http://launch.groups.yahoo.com/group/tuning/message/74155 12 note octave scales piano tuning instructions for 41edo]{{dead link}}


=== Full Keyboard Scales ===
=== Full keyboard retuning ===
(Terminology from [http://www.microtonal-synthesis.com www.microtonal-synthesis.com])
Tune each key of the keyboard to a different pitch. The pitches of the keys keep the property of being arranged in ascending order, but the octave pattern will be different, and there are larger amounts of retuning required. In addition, this method usually reduces the interval size you can play with a single hand, because pitches are more spaced out.


Tune each key of the keyboard to a different pitch. The pitches of the keys keep the property of being arranged in ascending order - but the octave pattern will be different, and there are larger amounts of retuning required.
Some synthesizers support full keyboard retuning, but not all. A compatibility list for various models can be found at [http://www.microtonal-synthesis.com Microtonal Synthesis]. Synthesizers supporting only 12-tone octave-repeating scales can be brought to support full keyboard scales with the help of the [https://sites.google.com/site/altkeyboards/integrator Midi Integrator] software, or the [http://www.tallkite.com/alt-tuner.html alt-tuner] software. Some virtual instruments, such as PianoTeq, also provide support for full keyboard retuning regardless of the physical controller used with it.


Some synthesizers support this, but not all (see, again, [http://www.microtonal-synthesis.com www.microtonal-synthesis.com]).
A possible "full keyboard scales" piano tuning for [[22edo]], mapping two keyboard octaves to one acoustic octave, is described in [http://lumma.org/tuning/erlich/erlich-decatonic.pdf Paul Erlich's paper on 22edo], on page 11.


Synthesizers supporting only 12 note octave scales can be brought to support full keyboard scales with the help of the [https://sites.google.com/site/altkeyboards/integrator Midi Integrator] software, or the [http://www.tallkite.com/alt-tuner.html alt-tuner] software.
In the case of acoustic instruments such as pianos, tuning full keyboard scales may even require major changes in construction. It has been done, however, to build instruments such as [[96edo#History|96edo]] pianos.


A possible "full keyboard scales" piano tuning for [[22edo|22edo]], mapping two keyboard octaves to one acoustic octave, is described in [http://lumma.org/tuning/erlich/erlich-decatonic.pdf Paul Erlich's paper on 22edo], on page 11.
=== Modulation wheel ===
Synthesizers, even without retuning functionality, often have a special functionality that is principally also suited for microtonality: the modulation wheel. Here are a few impressive examples of how to make microtonal music with the modulation wheel:
* [http://www.timomusic.ch/video_Spiros_Kottis.htm ''Spiros Kottis'' by timomusic]{{dead link}}
* [https://www.youtube.com/watch?v=g8gusUyO1Ts Piano cover of ''In the Bleak Midwinter''] by [[Stephen Weigel]] (based on Jacob Collier's cover)


In the case of acoustical instruments such as pianos, tuning full keyboard scales may even require major changes in construction. It has been done, however, e.g. on the [http://www.sauter-pianos.de/english/pianos/microtone.html 16th tone (96edo) piano].
This is, however, not a particularly easy way to do it...


=== Dynamic tunings ===
=== Dynamic tunings ===
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The easiest way to experiment with dynamic tunings is with midi keyboards and software. [http://www.huygens-fokker.org/scala/ Scala] and [http://www.nonoctave.com/tuning/LilMissScaleOven/ Lil' Miss Scale Oven] have limited dynamic tuning ability. [http://www.tallkite.com/alt-tuner.html Alt-tuner] allows retuning of individual notes (choosing among various ratios or among various EDO degrees), modulating to different keys (either by a specific interval, or to a specific note, or to the current bass note), and switching to completely different tunings. All this can be done via keyswitches, foot pedals, the mod wheel, or any control that generates a midi signal. These midi signals can come from any midi device, such as a 2nd keyboard, or even the computer's QWERTY keyboard. Technique-wise, using keyswitches would be similar to using mandals or sharpening levers, and using footpedals would be similar to using the classical harp's pedals.
The easiest way to experiment with dynamic tunings is with midi keyboards and software. [http://www.huygens-fokker.org/scala/ Scala] and [http://www.nonoctave.com/tuning/LilMissScaleOven/ Lil' Miss Scale Oven] have limited dynamic tuning ability. [http://www.tallkite.com/alt-tuner.html Alt-tuner] allows retuning of individual notes (choosing among various ratios or among various EDO degrees), modulating to different keys (either by a specific interval, or to a specific note, or to the current bass note), and switching to completely different tunings. All this can be done via keyswitches, foot pedals, the mod wheel, or any control that generates a midi signal. These midi signals can come from any midi device, such as a 2nd keyboard, or even the computer's QWERTY keyboard. Technique-wise, using keyswitches would be similar to using mandals or sharpening levers, and using footpedals would be similar to using the classical harp's pedals.


=== Get an alternative keyboard ===
=== Alternative keyboards ===
This is actually quite an old idea, since in historical tunings of the pre-well-tempered area, there was a demand for differing between flats and sharps.
{{Wikipedia|Isomorphic keyboard}}
{{Wikipedia|Category:Musical keyboard layouts}}
This is actually quite an old idea, since in many [[historical temperaments]], there was a demand for differing between flats and sharps. Minor variations to the common [[Halberstadt layout]], sometimes known as an [[Wikipedia:Enharmonic keyboard|enharmonic keyboard]], have been used to accommodate extra keys for such purposes, such as [[Wikipedia:Split sharp|split sharp]] keys. [http://www.denzilwraight.com Denzil Wraight's website] has some beautiful examples of historical harpsichords with up to 24 keys per octave. A list of existing church organs all over the world with split semitone keys can be found on [https://sites.google.com/site/iboortgies/tableoforganswithsubsemitones Ibo Ortgies' homepage].


http://www.denzilwraight.com has some beautiful examples of historical harpsichords with up to 24 keys per octave.
In modern times, the idea of alternative keyboards has come up again. Most alternative keyboard layouts can host the same fingering for multiple tunings, since most of them have been designed with 12edo in mind and can be generalized using the corresponding diatonic intervals. Many alternative keyboards are isomorphic keyboards, which allow layouts where each interval or chord has the same shape in every key. Any layout may be arranged in multiple ways on an actual instrument by changing the orientation of the layout, the number of keys, the angle between the axes, the key colors, etc.


A list of existing church organs all over the world with split semitone keys can be found on [https://sites.google.com/site/iboortgies/tableoforganswithsubsemitones Ibo Ortgies' homepage].
{| class="wikitable"
|+ Isomorphic keyboard layouts
! Layout
! Tiling
! 1st axis
! 2nd axis
! Complementary axis
|-
| [[Wikipedia:Generalized keyboard|Bosanquet]]/[[Wikipedia:Jankó keyboard|Jankó]]
| Hexagonal
| Major 2nd
| Minor 2nd
| Augmented 1sn
|-
| [[Wikipedia:Harmonic table note layout|Harmonic table]]
| Hexagonal
| Perfect 5th
| Major 3rd
| Minor 3rd
|-
| [[Wikipedia:Wicki-Hayden note layout|Wicki-Hayden]]
| Hexagonal
| Perfect 5th
| Major 2nd
| Perfect 4th
|-
| [[Wikipedia:Chromatic button accordion|Chromatic accordion (types B/C)]]
| Hexagonal
| Minor 3rd
| Major 2nd
| Minor 2nd
|-
| [[Wikipedia:Array mbira|Array mbira]]
| Hexagonal-ish
| Perfect 8ve
| Perfect 5th
| Perfect 4th
|}


In modern times, the idea of generalized keyboards has come up again. Generalized keyboards can host the same fingering for multiple tunings. See, for example:
Another way to generalize the Halberstadt layout is to use a different [[MOS scale]] to determine the layout of white and black keys. [[Stephen Weigel]] has used such layouts in several of his YouTube videos, including [[hanson]] ([[4L 3s]]) and [[porcupine]] ([[7L 1s]]) layout for [[15edo]], [[mavila]] ([[7L 2s]]) layout for [[16edo]], etc.
 
* [[Wikipedia: Isomorphic keyboard]]
* [[Wikipedia: Generalized keyboard]]
* [[Wikipedia: Robert Holford Macdowell Bosanquet]]
* [[Wikipedia: Harmonic table note layout]]
* [[Wikipedia: Wicki-Hayden note layout]]
* [[Wikipedia: Jankó keyboard]]


For electronic music, there is meanwhile a number of generalized keyboards that are available or are soon to be available, see following list.
For electronic music, there is meanwhile a number of generalized keyboards that are available or are soon to be available, see following list.


== List of generalized keyboards ==
== List of synthesizers with alternative keyboards ==
=== Generalized keyboards ===
{| class="wikitable sortable center-4"
{| class="wikitable sortable center-4"
|-
|-
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| [http://web.archive.org/web/20060101074917/http://www.thummer.com/ Thummer]
| [http://web.archive.org/web/20060101074917/http://www.thummer.com/ Thummer]
| Thumtronics
| Thumtronics
| 2-dimensional, hexagonal
| Wicki-Hayden
| 114
| 114
| Never produced
| Never produced
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| [https://hpi.zentral.zone/tonalplexus Tonal Plexus U-PLEX, TPX2, TPX2s]
| [https://hpi.zentral.zone/tonalplexus Tonal Plexus U-PLEX, TPX2, TPX2s]
| [http://hpi.zentral.zone/index Hπ Instruments]
| [http://hpi.zentral.zone/index Hπ Instruments]
| 2-dimensional, rectangular
| Square tiling, 17\205 × 1\205
| 422
| 422
| No longer produced (as of 2014)
| No longer produced (as of 2014)
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| [https://hpi.zentral.zone/tonalplexus Tonal Plexus TPX4]
| [https://hpi.zentral.zone/tonalplexus Tonal Plexus TPX4]
| Hπ Instruments
| Hπ Instruments
| 2-dimensional, rectangular
| Square tiling, 17\205 × 1\205
| 844
| 844
| No longer produced (as of 2014)
| No longer produced (as of 2014)
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| [https://hpi.zentral.zone/tonalplexus Tonal Plexus TPX6, TPX6s]
| [https://hpi.zentral.zone/tonalplexus Tonal Plexus TPX6, TPX6s]
| Hπ Instruments
| Hπ Instruments
| 2-dimensional, rectangular
| Square tiling, 17\205 × 1\205
| 1266
| 1266
| No longer produced (as of 2014)
| No longer produced (as of 2014)
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| [http://www.c-thru-music.com/cgi/?page=prod_axis-49 AXiS-49]
| [http://www.c-thru-music.com/cgi/?page=prod_axis-49 AXiS-49]
| C-Thru Music
| C-Thru Music
| 2-dimensional, hexagonal
| Harmonic table
| 98
| 98
| No longer produced
| No longer produced
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| [http://www.c-thru-music.com/cgi/?page=prod_axis-64 AXiS-64]
| [http://www.c-thru-music.com/cgi/?page=prod_axis-64 AXiS-64]
| C-Thru Music
| C-Thru Music
| 2-dimensional, hexagonal
| Harmonic table
| 192
| 192
| No longer produced
| No longer produced
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| [http://www.shapeofmusic.com/ Opal Chameleon, Opal Gekko]
| [http://www.shapeofmusic.com/ Opal Chameleon, Opal Gekko]
| Opal
| Opal
| 2-dimensional, hexagonal
| Harmonic table
| 192
| 192
|
|
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| [http://monome.org/ monome grid]
| [http://monome.org/ monome grid]
| monome
| monome
| 2-dimensional, rectangular
| Square tiling, mapping by coordinates (no default mapping)
| 128 (formerly 64, 128 or 256)
| 128 (formerly 64, 128 or 256)
| In production
| In production
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| [http://www.lippenskeyboard.com/ Lippens Keyboard]
| [http://www.lippenskeyboard.com/ Lippens Keyboard]
| Lippens
| Lippens
| Jankó (2-dimensional)
| Jankó
| 198
| 198
| Prototype
| Prototype
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| [http://daskin.com/page2/page2.html Daskin 5]
| [http://daskin.com/page2/page2.html Daskin 5]
| Daskin Manufacturing
| Daskin Manufacturing
| Jankó (2-dimensional)
| Jankó
| 203
| 203
|
|
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| [http://daskin.com/page2/page2.html Daskin 6]
| [http://daskin.com/page2/page2.html Daskin 6]
| Daskin Manufacturing
| Daskin Manufacturing
| Jankó (2-dimensional)
| Jankó
| 243
| 243
|
|
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| [https://www.lumatone.io/ Lumatone] / [http://www.terpstrakeyboard.com Terpstra keyboard]
| [https://www.lumatone.io/ Lumatone] / [http://www.terpstrakeyboard.com Terpstra keyboard]
| Cortex design
| Cortex design
| 2-dimensional, hexagonal
| Hexagonal tiling, customizable layout (default: Bosanquet)
| 280
| 280
| In production
| In production
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| [https://www.starrlabs.com/product/zboard2424/ ZBoard 24×24]
| [https://www.starrlabs.com/product/zboard2424/ ZBoard 24×24]
| Starr Labs
| Starr Labs
| 2-dimensional, rectangular
| Square tiling, customizable layout (default: perfect 4th × semitone)
| 576
| 576
| In production
| In production
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| [https://www.starrlabs.com/product/zboard/ ZBoard 12x24]
| [https://www.starrlabs.com/product/zboard/ ZBoard 12x24]
| Starr Labs
| Starr Labs
| 2-dimensional, rectangular
| Square tiling, customizable layout (default: perfect 4th × semitone)
| 288
| 288
| In production
| In production
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| [https://www.starrlabs.com/product/microzone-u648/ Microzone U-648]
| [https://www.starrlabs.com/product/microzone-u648/ Microzone U-648]
| Starr Labs
| Starr Labs
| 2-dimensional, hexagonal
| Bosanquet
| 288
| 288
| In production
| In production
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| [http://www.starrlabs.com/index.php?route=product/product&path=69/microzone-u-648&product_id=67 Microzone U-990]
| [http://www.starrlabs.com/index.php?route=product/product&path=69/microzone-u-648&product_id=67 Microzone U-990]
| Starr Labs
| Starr Labs
| 2-dimensional, hexagonal
| Bosanquet
| 810
| 810
| No longer produced
| Bosanquet
|
|
|-
|-
| [https://dualo.com/en/dualo Dualo Du-Touch S]
| [https://dualo.com/en/dualo Dualo Du-Touch S]
| Dualo
| Dualo
| 2-dimensional, hexagonal
| Hexagonal tiling, multiple layouts: dualo (major 3rd × semitone), diatonic dualo, Jankó, chromatic accordion
| 52
| 52
| In production
| In production
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| [https://www.striso.org/ Striso board]
| [https://www.striso.org/ Striso board]
| Striso
| Striso
| 2-dimensional, orthogonal
| Wicki-Hayden (but the tiling angle is not 60°)
| 61
| 61
| In production
| In production
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| [https://dualo.com/en/exquis/ Exquis]
| [https://dualo.com/en/exquis/ Exquis]
| Dualo
| Dualo
| 2-dimensional, hexagonal
| Hexagonal tiling, dualo layout (major 3rd × semitone)
| 61
| 61
| Taking preorders, announced for end of summer 2023
| Taking preorders, announced for end of summer 2023
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|}
|}


A special class of microtonal midi controllers are "keyless" ones:
=== Keyless controllers ===
 
{| class="wikitable"
{| class="wikitable"
|-
|-
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=== Pad controllers ===
=== Pad controllers ===
 
* [https://global.novationmusic.com/en/launch/launchpad-pro Novation Launchpad pro]
[https://global.novationmusic.com/en/launch/launchpad-pro Novation Launchpad pro]
* [https://www.behringer.com/behringer/product?modelCode=P0AJD Behringer CMD LC-1]
 
[https://www.behringer.com/behringer/product?modelCode=P0AJD Behringer CMD LC-1]


== External links ==
== External links ==
 
* [http://www.microtonal-synthesis.com Microtonal Synthesis] -  a database of synthesizers, samplers, digital pianos, electronic instruments, portable keyboards, sound cards and software synthesizers with user programmable microtonal scales or tunings: just intonation, non-12 equal temperament, well temperament, xenharmonics, etc.
* [http://sites.google.com/site/altkeyboards/ Alternative Keyboards group (on Google groups)]
* [http://sites.google.com/site/altkeyboards/ Alternative Keyboards group (on Google groups)]
* [https://www.facebook.com/notes/john-starrett/completely-generalized-keyboard/426265927629 John Starrett on Completely Generalized Keyboards] (Facebook Notes)
* [https://www.facebook.com/notes/john-starrett/completely-generalized-keyboard/426265927629 John Starrett on Completely Generalized Keyboards] (Facebook Notes)
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=== DIY links ===
=== DIY links ===
* [https://monome.org/docs/grid/kits/gridkit/ Monome Gridkit]: Monome DIY kit slashes price of pre-built one.
* [https://monome.org/docs/grid/kits/gridkit/ Monome Gridkit]: Monome DIY kit slashes price of pre-built one.
* [http://www.eecs.qmul.ac.uk/~andrewm/touchkeys.html TouchKeys Website]: There's a mapping in the TouchKeys software which splits each key into multiple regions specifically for microtonal music.
* [http://www.eecs.qmul.ac.uk/~andrewm/touchkeys.html TouchKeys Website]: There's a mapping in the TouchKeys software which splits each key into multiple regions specifically for microtonal music.
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* [http://synthzone.com/ctrlr.htm List of MIDI controllers on Synth Zone]
* [http://synthzone.com/ctrlr.htm List of MIDI controllers on Synth Zone]


=== Keyboard Concepts ===
=== Keyboard concepts ===
* [http://www.newkeyboard.de/ New Keyboard (Johannes Kotschy)]{{dead link}}
* [http://www.newkeyboard.de/ New Keyboard (Johannes Kotschy)]{{dead link}}
* [https://www.dodekamusic.com/learn/education-hub/playing-dodeka-keyboard/ Dodeka keyboard]     
* [https://www.dodekamusic.com/learn/education-hub/playing-dodeka-keyboard/ Dodeka keyboard]     
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