5bandEqualizer.js

var context = new (window.AudioContext || window.webkitAudioContext)();
var mediaElement = document.querySelector("audio");
var source = context.createMediaElementSource(mediaElement);

let band1 = document.querySelector("#band1");
let band2 = document.querySelector("#band2");
let band3 = document.querySelector("#band3");
let band4 = document.querySelector("#band4");
let band5 = document.querySelector("#band5");

var band1Filter = context.createBiquadFilter();
var band2Filter = context.createBiquadFilter();
var band3Filter = context.createBiquadFilter();
var band4Filter = context.createBiquadFilter();
var band5Filter = context.createBiquadFilter();

band1Filter.type = "peaking";
band1Filter.frequency.value = 60;
band1Filter.gain.value = 0;
band1Filter.q = Math.SQRT1_2;

band2Filter.type = "peaking";
band2Filter.frequency.value = 230;
band2Filter.gain.value = 0;
band2Filter.q = Math.SQRT1_2;

band3Filter.type = "peaking";
band3Filter.frequency.value = 910;
band3Filter.gain.value = 0;
band3Filter.q = Math.SQRT1_2;

band4Filter.type = "peaking";
band4Filter.frequency.value = 4000;
band4Filter.gain.value = 0;
band4Filter.q = Math.SQRT1_2;

band5Filter.type = "peaking";
band5Filter.frequency.value = 14000;
band5Filter.gain.value = 0;
band5Filter.q = Math.SQRT1_2;

const filters = [
	band1Filter,
	band2Filter,
	band3Filter,
	band4Filter,
	band5Filter,
];

source.connect(band1Filter);
band1Filter.connect(band2Filter);
band2Filter.connect(band3Filter);
band3Filter.connect(band4Filter);
band4Filter.connect(context.destination);

[band1, band2, band3, band4].forEach((band, index) => {
	band.addEventListener("input", () => {
		filters[index].gain.value = band.value;
	});
});

An ANCTUAL JavaScript 5 band Equalizer

Implementation of a 5 band equalizer in JavaScript. The frequencies chosen are copied from the same frequencies the native android equalizer uses.

An Equalizer is not a freaking visualizer. Damn all those articles that put JavaScript visualizer in their title when the article clearly just shows how to make a visualizer !!!

I may have made some mistakes because of my lack of knowledge in sound production, do go ahead and correct me🙂