Guitar amplifier

First of all: headphones

This tool sends the audio input to the speakers — that is what it does. With speakers open the sound goes back into the microphone, gets amplified again, goes back in again, and within two seconds it is a howl that builds on its own.

With headphones it does not happen. It is the one warning on this page that is not a footnote.

What it does

It takes what comes in from the sound card and builds an amplifier’s chain on top of it: gain, distortion, tone control, volume and cabinet. Three channels change the kind of distortion — not just the amount — and each arrives with its own tone and its own gate.

The three channels

Clean rounds the peaks and leaves the rest alone: it compresses by about an eighth at half scale, which is enough to sound like an amplifier rather than a cable.

Rock is a crunch: it breaks up when you dig in and cleans up when you ease off. It is the channel that answers the hand most.

Metal is high gain, with the bass taken out before the distortion and the gate on. The bass goes first because bass held inside heavy distortion turns to mud: every high-gain amplifier has less of it at the input than it has at the output.

The three curves are three points on one family, with a single knob — hardness. That is not a simplification: it is what makes it possible to state, and to check, that metal compresses more than rock and rock more than clean. Three unrelated formulas would be three places to get zero wrong.

About the cabinet

A twelve-inch speaker in a closed box passes almost nothing above five thousand hertz. Those six thousand hertz are the difference between “distorted guitar” and “broken radio”: with no cabinet, a distortion has harmonics all the way up and sounds like a buzz.

Here the cabinet is made of filters rather than a recorded impulse response, because an impulse response is an audio file to download and this site downloads no samples. It is what everyone did before IRs, and it is enough to tell whether a sound is the right one.

About the gate

It closes the input when you are not playing, which at high gain is the difference between a rest and a hiss.

Two thresholds, not one. It opens at −45 dB and only closes again below −55: with a single threshold a signal hovering around it would open and close on every measurement, and the hiss the gate was meant to remove would become a hiss that pulses.

About latency

The number on the page is what the browser declares: the delay of its audio graph plus the sound card’s, where it exposes it. Firefox does not expose the second, and then the number is declared as a lower bound instead of being made up.

Under ten milliseconds you do not notice it; over twenty you play badly. It is here to explore sounds: a browser’s latency is no substitute for a dedicated amplifier, and this line exists so that nobody discovers it while trying to record a part in time.

About the recording

It records the processed output — what you hear, cabinet included. You can play it back on the page and download it.

The format depends on the browser and is written next to the file: almost always Opus inside a WebM container. A file downloaded without knowing what it is, is a file that will not open later.

What is not here

It does not record the dry guitar alongside the processed one, it does not save your settings and it has no tuner: that is another page.

About your data

Everything happens in your browser. The audio is not sent anywhere, and the recording stays in memory until you download it or close the page.