synth 1

Figure 2 summary

• trigger envelope
• set attack and decay
• MIDI to Hz
• line object
• amplitude envelope

A simple 1 oscillator synth

We need some sounds. If we take a [osc~] oscillator and multiply it by a falling line that will give us a basic decaying tone. The [osc~] oscillator has frequency as its first control inlet and one audio signal output. We want an amplitude envelope control signal that starts off at maximum and decays away to zero. The [line~] generator takes message arguments of the form (level to go to, time to get there), so a message [1 0( will send the line to a value of 1 in 0 milliseconds. Sending a further message like [0 700( will set it moving back to zero over 700 ms. [1 0, 0 700( is a pair of messages in a single message box. The comma causes both messages to be sent in left to right order instantly, so this will send the line to one in 0 milliseconds, and then back to zero in 700ms. A line envelope is a powerful component of more complex controls, we will also meet its more versatile brother [vline~] shortly. The result of multiplying the sinewave signal by the line is a pure tone that decays away.

MIDI control of frequency

In order to control this synth with MIDI notes instead of Hz frequency let's add a [mtof] object. Notes appearing at the [inlet] will now be converted to Hz before being sent to the oscillators frequency inlet.

Figure 2: synth1

B-synth1.pd