Musical instruments for musicians and non-musicians: Controls

Other posts in the series Musical instruments for musicians and non-musicians:

  1. Part One: Controls: Analysing how continuous or discrete controls on the sound affect playability to great extent
  2. Part Two: Constraints: How embedding musical theory as constraints makes the instrument easier and more rewarding
  3. Part Three: Exotic examples: Examples of exotic instruments and how they achieve good or not so good results
  4. Part Four: Put into practice: Let’s put theory into practice to build an easy and musically-sounding Theremin

How can we design musical instruments that both musicians and non-musicians can play and enjoy?

“A musical instrument is an object constructed or used for the purpose of making music. In principle, anything that produces sound can serve as a musical instrument.” (Wikipedia)

What is a musical instrument?

In practice, nobody hardly calls a hammer a musical instrument, and hardly anybody considers an iPod as a musical instrument either. These two objects are missing something essential: the hammer is missing a way to assist the player in making musical sounds, whereas the iPod is lacking critical control to shape and alter the music in real-time.

Intuitively, musical instruments are tools to make music that are convenient for that purpose, and that provide enough live control to the human player.

Simple claves
Claves, perhaps the simplest instrument

Therefore, to design a musical instrument, we need to address:

  1. A way to generate sounds (every way to originate sounds is classified here); we won’t discuss that point in this post
  2. A way for musicians and non-musicians to make music easily, musical assistance (we will discuss this point partially in this post)
  3. A way for musicians and non-musicians to control the music being made: plenty of control (we will discuss this point in detail in this post)

For non musicians, it is obvious we have to address point 2 (musical assistance) more, whereas for musicians point 3 (plenty of control) will probably be the most important one, otherwise they will be frustrated.

Of course the later two points are conflicting, so the design of a musical instrument will require finding a balance between them.

Musical controls: Playability Vs. Expressiveness

“Playability is a term in video gaming jargon that is used to describe the ease by which the game can be played” (Wikipedia).

Here we will say an instrument has a good playability if it is easy to play, by musicians and especially by non-musicians.

Music is made of sounds that share essential attributes (the list is far from complete):

  • Pitch: this represents how “high” or “low” a sound is. Women typically sing at a higher pitch than men
  • Rhythm: this represents how the sounds are distributed over the metrical grid, in other words the pattern of sounds and silences
  • Articulation (the transition or continuity between multiple notes or sounds, e-g. linked notes -legato- or well separated notes)
  • Tempo: this represents the overall “speed” of the music
  • Dynamics: this represents how “loud” or “soft” a sound is
  • Timbre: this is the “colour” of the sound, as in “a piano has a different timbre than the saxophone”; we can sometime talk about “brighter” or “duller” timbres, etc.
  • Special effects and Modulations: electronic effects are endless, and so are modulations; most well-known modulations are the vibrato of the singer, or the special way to “slide” the start of notes on the saxophone.

Pitch and Rhythm are by far the primary controls, and the playability of an instrument is strongly linked to them: an instrument that is difficult to control in pitch or rhythm will surely be particularly difficult.

On top of pitch and rhythm, every musician, experienced or not, demand enough other controls to be as expressive as possible

Continuous pitch Vs. discrete pitch

Continuous pitch instruments can produce sounds of any pitch (lower or higher note) continuously, such as the violin, cello, theremin or the human voice (and also the fretless bass guitar).

Discrete pitch instruments are represented by the piano, flute, trumpet, the usual guitar, every instrument with a keyboard or with no frets, valves, or explicit finger positions.

continuous pitch instrument, particularly hard to play
continuous pitch instrument by Feromil, particularly hard to play

Because discrete pitch instruments already enforce automatically that every note played must belong to at least a scale (usually a chromatic scale), they are considered easier to learn and to play as opposed to continuous pitch instruments, where the player must find out the notes a priori using his/her ears alone (although after a deep training it will become instant habit).

Discrete pitch instruments have a better playability than continuous pitch instruments.

The chromatic scale contains 12 notes, out of which the (main) tonality of a song usually only uses 5 to 7 notes (diatonic, pentatonic or blues scales). It is usually up to the player to practice intensively to be able to play in any such sub scale without thinking about it, but one could imagine a simpler to play instrument that could be configured to only propose the notes that you can play with within a song (to be rigorous we should then deal with the problem of modulation, but it would bring us too far).

In contemporary music, instruments are sometimes expected to support microtonal scales, i.e. much more than 12 notes.

The great advantage with continuous pitch instruments is that they offer extreme control on the pitch and its variations: one can create a vibrato on a violin by quickly wobbling the finger on the fingerboard, or create a portamento by moving slowly between notes. The counterpart for that control is the huge training effort required.

Some instruments with a fixed pitch (simple drums, triangle, claves, wood sticks etc.) are obviously the easiest to use with respect to the pitch.

Playing in rhythm Vs. quantized playback

Most classical instruments require you trigger the sound at the right time with no help: you have to feel the rhythm, and then you must be accurate enough with your hands to trigger the sound (hit the drum, bow the string etc.) when you want it to be triggered. Again, this often requires training. By analogy with the pitch, we can consider that a continuous control of the rhythm .

Playing the pads on the MPC to trigger sounds
Playing the pads on the MPC to trigger sounds or to record a rhythmic pattern

Electronic groove boxes (Akai MPC in particular) and electronic sequencers do take care of triggering sound accurately on behalf of the musician, thanks to their quantization mechanism: you play once while the machine is recording, then the machine adjusts what you played against a metrical grid, and then repeats the “perfect” rhythm forever. We can consider that as a discrete control of the rhythm.

Pitch-Rhythm / Continuous-Discrete Controls instruments chart
Pitch-Rhythm / Continuous-Discrete Controls instruments playability analysis chart

Note that the grid does not have to be rigid as one can imagine, it can accommodate very strong swing, and quantization can also be applied partially, to fix a little while keeping some of the subtle human timing inaccuracy that can be desirable.

Discrete rhythm instruments (quantized rhythm) have a better playability than continuous rhythm instruments.

Talking about rhythm, the theremin is a bit special since a note is hardly triggered, instead one just controls the sound intensity (dynamics) with the loop antenna on the left. The rhythm is more than continuous…

Realtime quantization can only adjust notes later in time. One could imagine an instrument where notes can only be triggered when two conditions are met: when the player requests a note, and when a machine-generated rhythmic grid triggers a pulse. This would be a form of realtime quantization, which would make the instrument more accessible to non musicians, especially if they are poor in rhythm.

A vintage analogue step sequencer is an electronic device with buttons to decide whether to sound or not and a knob to adjust the pitch of the sound for each pulse of a fixed rhythmic grid. Each column of buttons and knobs is scanned in turn to trigger sounds for each beat. Playing such a sequencer does not require timing accuracy (it is a discrete rhythm instrument) but requires accuracy to set each independent pitch (because it’s set with a rotating know it is a continuous pitch instrument).

To sum up the analysis of pitch and rhythm controls as being either continuous or discrete (or none), here is above a simple chart that shows various instruments sorted by their continuous or discrete pitch and rhythm controls. It reads like this: “Violin is a continuous pitch and continuous rhythm instrument, a groove box is has no control on pitch and is a discrete rhythm instrument”.

The more we move to the upper right corner, the most difficult the instrument usually is (and probably the most expressive as well). The more we more down to the bottom left corner, the easier the instrument is (and probably the most frustrating as well). We therefore have defined a criterion to estimate the playability (or the other way round, expressiveness) of an instrument.

Guitar Hero has been put in the chart, in the bottom left corner, whereas it is not an instrument (as judged by a U.S. Court), since the actions on the fake guitar do not control any sound at all, they only enable to increase ones score.

Expressiveness through other controls

Strange instrument by Jean-François Laporte (Can)
Strange instrument by Jean-François Laporte (Can)

As listed above, playing music makes use of many controls in addition to pitch and rhythm.

Many classical instrument that rely on physical principles (string, air pressure…) provides to the musician a lot of natural controls: changes in the way a sax player breathes, hitting a drum in the center or near the outside, sliding changes in pitch on a string etc.

Electronic instruments used to be rather poor with respect to the expressive potential they provided, however there is now a huge range of devices that help modulate the sound in realtime: pedals, breathe controllers, knobs and sliders, keyboard aftertouch (pressure sensitivity after the key has been pressed).

Various modulation wheels for electronic keyboards from various manufacturers
Various modulation wheels or devices for electronic keyboards from various manufacturers

Typical modulation controls for electronic keyboards control the pitch bend (how to modulate the pitch continuously, by derogation to the discrete pitches of the keyboard), and the vibrato (again a fast and vibrating modulation of the pitch, also by derogation to the discrete pitches of the keyboard). They are often wheels, and sometimes joystick or even touchpad.

A turntable can be considered an instrument, a very limited one, if it provides a way to play a record at a faster or slower pace, hence controlling the tempo.


Non musicians prefer instruments with less control, or with discrete controls that are easier to get right, so that they can have fun without the risk of being out of tune or out of rhythm. We have reviewed this reflection for the primary musical controls: pitch and rhythm, including a way to estimate their playability.

Homemade breakbeat controller by Michael Carter aka Preshish Moments (USA)
Homemade breakbeat controller by Michael Carter aka Preshish Moments (USA)

However, when non-musicians become really interested in getting closer with music they do not want a one-button does it all music box such as Beamz. They want, just like professional musicians, to have enough control to express emotions through the instrument.

On the other end, being both a continuous pitch and a continuous intensity instrument, the theremin is definitely one of the most difficult instrument to play: “Easy to learn but notoriously difficult to master, theremin performance presents two challenges: reliable control of the instrument’s pitch with no guidance (no keys, valves, frets, or finger-board positions), and minimizing undesired portamento that is inherent in the instrument’s microtonal design” (Wikipedia).

This series of post follows a recent and very interesting discussion with Uros Petrevski. Many pictures were shot at the Festival Octopus in Feb 2009.


Software development, Domain-Driven Design, patterns and agile principles enthusiast