Designing Innovative Electronic Musical Instruments
Designing Innovative Electronic Musical Instruments
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Why the Piano's Note Layout Doesn't Work for Expressive Musical Control, but LinnStrument's Fourths String Layout does
Piano Note Layout
4ths String Layout
When I (Roger) first started designing LinnStrument, I considered making its flat 3D-sensing rubber pads in the shape and arrangement of piano keys. However, I soon discovered that the piano note arrangement presented too many problems for a 3D-expressive controller. So after researching a variety of note arrangements, it became clear that a stringed instrument layout--multiple rows of consecutive semitones overlapping in pitch-- was superior and solved the piano's problems:
Problem 1: The piano's pitch intervals aren't uniform and the black keys are located behind the white keys
On an expressive controller, the most intuitive way to perform pitch slides and bends is to slide your finger directly from one note to another. Because of the uneven pitch intervals of a piano's white keys, a pitch slide from B to C results in semitone pitch change whereas a slide from C to D (the same distance) results in a whole tone pitch change. Sliding up an octave results in a series of uneven pitch jumps. Further, sliding from a white key to a black key requires a diagonal movement, which requires changing your Y-axis position.
This also presents a problem for vibrato, a common expressive pitch gesture. If a white key has a half-tone interval on one side and whole-tone interval on the other, a performed vibrato will be asymmetrical, with twice the pitch movement on the whole-tone side than on the half-tone side.
Also, because the black keys are about half the length of the white keys, they have only half the Y-axis range of the white keys. FInally, it's not isomorphic--for each chord or scale, you must learn a different fingering for each of the 12 musical keys.
LinnStrument's stringed-instrument layout has none of these problems. Because the interval between adjacent notes is always a semitone, pitch slides are always uniform, vibratos are always symmetrical, each note has exactly the same Y-axis range, and when the rows are tuned to the same interval (as in the default fourths tuning), it is fully isometric-- for each chord or scale, the same fingering is used for all 12 musical keys.
Problem 2: The piano's notes are arranged in one long single line
Why? Because a few centuries ago, there needed to be a string behind each key, a requirement that no longer exists in electronic controllers. This presents a few problems.
First, if the left hand is playing bass notes and the right is playing treble notes, the hands are too far apart to watch both at the same time. Second, there is only one instance of each pitch, so you can’t play the same note in different hands at the same time, or play chords and melody in the same pitch range. Third, you can't stretch more than a musical tenth interval in one hand. Fourth, it's not very portable.
LinnStrument's stringed-instrument layout has none of these problems. Because of its overlapping rows of notes, the hands are always fairly close together and therefore easy to see both, each pitch has multiple locations making it possible to play the same note in both hands, and you can stretch up to 3 octaves in one hand. In the default fourths tuning, its 200 note pads provide a five-octave range (due to the overlapping pitches), same as a standard MIDI keyboard. And at 22.5 inches long by 8.25 inches wide by 1" thick and only 5 pounds, it's much lighter and more portable.
The Fourths String Layout:
The Emerging Standard for Expressive MIDI Control
Like strings on a guitar, LinnStrument's rows of consecutive semitones can be tuned however you like. But the most popular tuning—and LinnStrument's default tuning—is in intervals of musical fourths (five semitones between rows), which is like a bass guitar or the lower four strings of a guitar. The name for this is the "Fourths String Layout". This note arrangement turns out to provide the ideal note density for chords and scales, yet still provides a full five octaves of pitch range on LinnStrument, same as a standard MIDI keyboard, or four octaves on LinnStrument 128.
And others have noticed this too. It's a standard note arrangement in Ableton Push, ROLI Blocks and the GeoShred, GeoSynth and Musix Pro apps for iPad. Plus, of the five MPE Controllers available today, four of them—LinnStrument, Continuum, SoundPlane and Eigenharp—abandoned the piano keyboard because of its problems for expressive performance. And three of those—LinnStrument, SoundPlane and Eigenharp—arrange the notes in a grid and LinnStrument and SoundPlane use the 4ths String Layout by default.
What makes the Fourths String Layout worthy of so much attention? Two reasons:
1) The most natural and intuitive way to perform pitch bends and note-to-note pitch slides is to slide your finger directly from the starting note to the ending note. This requires that the semitones are arranged consecutively in rows, just like a string of a stringed instrument.
2) Like any stringed instrument, multiple rows of consecutive semitones permit easier chords and scales than a single string. So the only question is "What is the best pitch interval between rows?" Fifths tuning (7 semitones as on violins and cellos) is isomorphic and works well for solos, but is too great an interval to finger many common chords in one hand. Thirds tuning (4 semitones) is isomorphic and permits playing most chords in one hand, but the total pitch pitch range of the playing surface is too limited. Guitar tuning is very popular, but isn't isomorphic because of the odd third interval between the G and B strings, requiring different fingerings when the same chord is played on different rows. But fourths tuning (5 semitones) permits easy fingering of any chord or scale, provides a very good total pitch range, and is isomorphic.
When I (Roger) designed LinnStrument's note layout, I could have made LinnStrument's flat 3D-sensing rubber pads in any shape and arrangement. Once I recognized the problems of the piano layout, I explored many of the innovative note layouts that have been proposed recently and over the centuries, including the Janko and hex layouts like the Harmonic Table or Wicki/Hayden. Each of these note arrangements has its merits, but none permitted the intuitive note-to-note pitch slides made possible by rows of consecutive semitones. I then briefly considered a hex layout consisting of horizontal rows of consecutive semitones tuned 4.5 semitones apart, but the grid layout seemed more intuitive and easier to finger chords and scales. In the end, it became clear to me that the Fourths String Layout is the best and most intuitive choice for expressive musical performance of both chords and scales, as demonstrated in these videos:
Soloing in Fourths String Layout
Chords in Fourths String Layout