kslider

This is a bare-bones monophonic MIDI synthesizer that uses the pitch and velocity information from incoming MIDI note messages to control the frequency and amplitude of a sawtooth waveform. 

This patch uses the MIDI key number (pitch) data byte to set the frequency of a sawtooth oscillator, and it uses the velocity data byte to set the amplitude of the oscillator. Note-on velocity values in the range 1-127 are mapped to a range of decibels from -60 to 0, and those decibel values are then converted to linear amplitude values to scale the amplitude of the oscillator.

This patch uses the vtoa abstraction (found here) to convert MIDI velocity to amplitude which controls the volume of a saw~.

This patch is an example of a sampling synthesizer in Max. The kslider may be used to control the patch if a MIDI controller is not available. The gtrvoice patch used inside of the patcher guitar6strings may be found in the example Managing samples in Max. The guitar samples that are loaded into the buffer subpatch may be found in the file called guitarstrings.zip.

When you play a note with MIDI, you usually want the note to sustain as long as the key is held down, then you want it to turn off (either immediately or gradually) when the key is released (when the note-off message is received). Because MIDI is designed to function in real time, in live performance, there is no duration information contained in a note-on message. The duration can only be known once the key has been released.

This example shows how to play sound files preloaded into sfplay~ using a MIDI keyboard with the select object.

This example shows different methods for using the select object.

This example shows how to get a complete list with all currently played notes using bag object. In this example we are also using the thresh 0 object in order to output all notes being held by bag as a single list.

As a demo project to explore JavaScript programming in Max, this patch implements a script that harmonizes any played MIDI note with either a major seventh chord or a minor seventh chord that contains the played note. For any given pitch, there are four different major seventh chords and four different minor seventh chords that contain that pitch.

An ADSR envelope generator is a common tool for controlling the amplitude of a note, and in fact it can be used to control any parameter of a sound. In this example, one adsr~ object controls the amplitude of a note while another adsr~ controls the cutoff frequency of a lowpass filter on the sound. Both are triggered at the same moment, but they have slightly different parameters for independent envelope shapes.

One of the earliest methods of digital sound synthesis was a digital version of the electronic oscillator, which was the most common sound generator in analog synthesizers. The method used was simply to read repeatedly, at the established sample rate, through a stored array of samples that represent one cycle of the desired sound wave. By changing the step size with which one increments through the stored wavetable, one can alter the number of cycles one completes per second, which will determine the perceived fundamental frequency of the resulting tone.