EX / Hz.Plugins / Hz.Osc (Phase Modulation)

Intro

Hz.Osc has an optional phase modulation (audio) port. We can connect one instance to another to get gnarly sounds.

The Setup

First we connect two Hz.Osc nodes.

let pm = scene.NewAnode("Hz.Osc", {name:"PM"});
let inst = scene.NewAnode("Hz.Osc", {name:"Inst", cfg:"stereo"});
let dac = scene.GetDAC();
scene.Chain(pm, inst, dac);

Note that our phase-modulating oscillator is a mono (default) configuration, while our instrument is stereo.

Next we set up some default parameters and present the Webview GUI.

// set up our phase modulator
const sq = pm.GetParamValueForMenuItem("Waveform", "SquareTab");
pm.SetParam("Waveform", sq);

// configure the instrument oscillator
inst.SetParam("Waveform", 0);
inst.SetParam("PMScale", 2); // the amount of the PM effect.
inst.SetParam("/adsr/R", .05);
await scene.Sync();

// We raise the webview interfaces via hzplugins tab. 
// There you can manually adjust the PM Amplitude (and other params) for
// dramatic affect.  Since Hz.Scope is active you can explore how
// the phase modulation affects the signal spectrum. 
inst.Show();
pm.Show();
await scene.Wait(0); // make sure scene.Now is up-to-date.

Finally, we play some notes and progrmatically modify the PM frequency via its Transpose parameter.

let durS = .25;
let dur = scene.Seconds(durS);
let when = scene.Now() + dur;
for(j=0;j<10;j++)
{
    // modify the frequency of the modulator relative to the current key.
    pm.SetParam("Transpose", 2*(j-5));
    for(let i=0;i<15;i++)
    {
        let key = 50 + i;
        pm.Note(key, .9, dur, when); 
        inst.Note(key, .9, dur, when); 

        when += 1.3*dur;
        await scene.Wait(dur);
        yield;
    }
}

See Also

Hz.Osc Misc