Why does the original pitch disappear?

Because multiplication produces only the sum and difference of frequencies, not the originals. A tone multiplied by a steady carrier comes out as two tones either side of it, which is why the harmonic relationships that identify the sound are replaced and the result seems to have no obvious pitch.

What does the carrier frequency control?

The distance between the two shifted copies of the spectrum. A low carrier spreads them narrowly and produces a discordant, robot-like sound; a high one separates them widely so the difference components fall into the audible band as a lower, bell-like tone.

Why does the phase matter?

Because the two copies of the spectrum carry opposite signs in one of the two phase states, so which components reinforce and which cancel depends on it. The practical consequence is that at ninety degrees the carrier tone itself is suppressed, which removes the whistle that would otherwise sit over the effect.

Why is there no mix control?

Because the effect is a multiplication, so a partial mix would not be a partial ring modulation but simply the dry signal added to the modulated one — a different sound rather than a proportion of the same one. The character comes from the whole signal being multiplied.

What happens at very low carrier frequencies?

The two copies of the spectrum end up so close together that the effect stops being heard as a change of pitch and starts behaving as an amplitude modulation, which is a tremolo-like flutter rather than a metallic tone.

Ring Modulator

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Ring Modulator multiplies a recording by a steady tone, which replaces its harmonic structure with sum and difference frequencies. The result is metallic, bell-like or robotic depending on the carrier frequency.

What is Ring Modulator?

Set the carrier frequency and phase, drop a file, and process; the footer explains what the carrier does to the spectrum.

The controls:

A carrier frequency from one to twelve hundred hertz, defaulting to seventy.
Four presets with their own phase settings: a robot at thirty hertz, a dalek-like effect at seventy, a science fiction setting at two hundred and thirty with the phase at ninety degrees, and a metallic one at six hundred and forty.
A carrier phase from zero to three hundred and sixty degrees in fifteen degree steps.
A footer explaining that the output contains the original frequencies plus and minus the carrier, and that the carrier itself is suppressed when the phase is ninety degrees.

The operation is a multiplication rather than an addition, and that is what makes it sound unlike anything else. Multiplying two signals produces new frequencies at the sum and difference of every pair of components, so a single tone of a given pitch entering the tool comes out as two tones, one above and one below the original by the carrier frequency, with the original itself gone. Applied to a complex sound the effect is dramatic: the harmonic series that gave the sound its identity is replaced by two shifted copies of it, which is why the output reads as metallic or bell-like rather than as a filtered version of the input. The carrier frequency sets the interval between the two copies, so a low carrier produces widely spaced mirror images that sound discordant, while a high one pushes the difference components down into the audible range and the sum components above it. The phase control is subtle but worth understanding. At zero the carrier is a pure cosine, and at ninety degrees it is a pure sine; because the two components of the output carry opposite signs in one of those cases, the phase decides whether the two copies reinforce or cancel in particular spectral regions. The footer's claim that the carrier is suppressed at ninety degrees is the practical consequence: at that phase the carrier tone itself is removed from the output, which matters when the carrier would otherwise be audible as a whistle over the top of the effect. Very low carrier rates stop being a metallic effect at all and act as an amplitude modulation instead.

What it does not offer:

No wet and dry mix, so the effect is always applied fully.
No control of the carrier's waveform.
No tracking of the input pitch.
The carrier is not filtered out of the output except by the phase setting.
No stereo offset between the channels.
Output is sixteen bit WAV.

Use it for deliberate effects: a robotic voice, a bell-like tone from a sustained sound, science fiction textures, or a subtle metallic edge at a high carrier setting. When the modulation should be in the level rather than the spectrum, the tremolo applies a raised cosine instead, and when the target is harmonic saturation rather than spectral shifting, the distortion and the bitcrusher are the tools for that.

How to use Ring Modulator

Drop an audio file onto the panel.
Set the carrier frequency, starting with a preset if you want a known character.
Adjust the phase, using ninety degrees if the carrier itself should not be heard.
Process the file and download the ring modulated WAV.

When to use Ring Modulator vs related tools

Ring Modulator is the tool when the spectrum itself should be moved rather than shaped, which is how robotic and bell-like effects are made. Tremolo Effect modulates the level using a smooth curve instead of multiplying. Distortion Effect and Bitcrusher Effect change the signal by reshaping it rather than by multiplying it, and Telephone Effect narrows the band to imitate a transmission.

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