User’s Guide

The Melody Stochaster is meant for playing stochastic, or random, melodies, that are based around a melody you feed it.  These melodies are played back with a timbre that randomly moves through a space of square, saw, and triangle waves.  However, you can also play the instrument like a traditional synthesizer using this random timbre movement.  You use the upper part of the interface to use the instrument in this manner.

Play Mode

Use these controls for Play mode

Controls for Play mode

The radio buttons under the Play button let you choose between two playing modes.  In the first, you have one timbre per note – every time you play a note, the timbre changes according to the other settings, and future notes you play won’t affect the notes you are sustaining.  In the second, you have one timbre at a time – each time you play a note, the timbre of all notes changes according to the other settings, and all notes have the same timbre.  You can hear the difference between these two modes:

In one timbre per note, pressing keys while other keys are pressed does not change the sound of the sustained notes.

In one timbre at a time, pressing keys while other keys are pressed changes the sound of all notes playing. Listen to the same excerpt but played in the other mode:

The cutoff settings control a low-pass filter, which all sound is routed through.  The Base Cutoff is the lowest the cutoff for the low-pass filter will ever be.  The Cutoff Sensitivity affects how much your note velocities open the filter.  When this is set to 0, the low-pass filter cutoff will always be the base cutoff.  When this is set to 1, the low-pass filter will be completely open when you play midi notes with a velocity of 127.

Here’s three examples of the filter in action: one with a low base and a high sensitivity (so the filter can have a wide range of cutoff frequencies), one with a high base (only high cutoff frequencies), and one with a low base and low sensitivity (only low cutoff frequencies).

The Timbre Flux setting affects how quickly the sound moves between the levels of the square, saw, and triangle waves.  A setting of 1 will move the timbre a barely noticeable amount each note, while a setting of 100 will move the sound to fully square, saw, or triangle on each note.

Here the difference between low timbre flux (sound barely changes) and high timbre flux (sound changes rapidly) in these examples:

IMPORTANT: After using Play mode, you must exit ChucK manually. Also, when you are using this mode, if you change any settings, you will not observe any difference until you exit ChucK and click the Play button again.  The steps for exiting ChucK are here.

Play Melody Mode

The main feature of the Melody Stochaster is to create stochastic melodies.  To do this, there are two steps:

First, load or record an input melody.  When deciding on an input melody, keep the following in mind:

  • The output melody will have the same pitch content as the input.  It will only play the notes you played, at approximately the rates you played them; however, any original sense of order between notes is lost.
  • The output melody will have the same range of note velocities as the input.  In this case, only the softest and loudest note set anything.
  • The output melody will have the same range of note and rest lengths as the input.  The statistics of rests and “negative rests” (i.e. chords) are treated separately.
Use these controls for loading an input melody

Controls for loading an input melody

You can use the Load File button to load a midi file from your filesystem to use as the input for melody stochastion.

Or, you can record your own melody.  When you click the Record button, an instance of Play will be started so you can hear yourself record.  When you are done, press Stop Recording (the same button as Record).  Later, if you want to save this recording to your filesystem, you can use the Save Recording button.

After you have loaded an input, use the melody stochastion settings to create and play a stochastic melody.

Use these controls for Play Melody mode

Controls for Play Melody mode

The Base CutoffCutoff Sensitivity, and Timbre Flux work the same as above.

The Octaves Below/Above Source settings allow you to add additional notes into the output.  As an example, if your input consisted only of C4, and you had Octaves Below/Above set to [-1, 2], then you might hear C3, C4, C5, and C6 in the output.  The output will not jump randomly between octaves each note, but instead has a small chance to switch the octave it is currently in at each note.  These can range from -8 to 8 (and the program will enforce that Below is not less than Above), but usually these extremes do not sound very good, and it is recommended to spend most of your time within [-4, 4].

Listen to the following example which demonstrates the octave settings.  It starts in [0,0] then moves to [1, 1], followed by [-1, -1], then [-1, 1].

The Speed Factor button affect note and rest lengths.  If the Speed Factor is 1.0, it will have no effect.  If it is 2.0, the output will be played at twice the speed of the input.  If it is at 0.5, it will be played at half the speed of the input, etc.  The possible range of values for the speed factor are 1/10 to 10.  Many users report more audibly pleasing results at speeds greater than 2.0 and less than 8.0.

Listen to the following example which demonstrates the speed factor.  It starts at 1.0, then slows down, then starts again at 2.5, then speeds up (in obvious jumps).

When you have the settings you want, press Play Melody to compute the stochastic melody and start playing it.  If you want to save the melody that is currently playing, you can click Save Melody to save it as a midi (.mid) file.  To stop the sound, press Stop Playing or exit the program.

IMPORTANTYou may alter any of the settings while the melody is playing.  However, every time a setting is altered, a new melody is calculated, so if you want to use Save Melody, do so before you alter any settings!