chp.scd

// cf. https://github.com/brunoruviaro/SynthDefs-for-Patterns/blob/master/laserbeam.scd
(
SynthDef("laserbeam", {
    arg out = 0, pan = 0.0, freq = 440, amp = 0.1, dur = 0.25;
    var snd, freqenv, ampenv;
    // frequency envelope
    freqenv = EnvGen.ar(Env([1, 0.25], [dur/2]));
    // amplitude envelope
    // no gate: fixed-time envelope, self-terminating.
    ampenv = EnvGen.ar(
        envelope: Env([1, 0], [dur/2]),
        levelScale: amp,
        doneAction: 2);
    snd = LFTri.ar(freq: freq * freqenv, mul: ampenv);
    // snd = SinOsc.ar(freq: freq * freqenv, mul: ampenv);
    Out.ar(out, Pan2.ar(snd, pan));
}).add;
)

(
    Pbind(
        \instrument, "laserbeam",
        \pan, Pwhite(-1.0, 1.0),
        \midinote, Pwhite(140, 144),
        \amp, 0.5,
        \dur, 0.25;
    ).play;
)

Env.new([1, 0.25], [0.125]).plot;