What is the difference between a chirp and a sweep?

Direction and repetition. A chirp modulates the frequency continuously in a cycle, so it rises and falls again and again for the whole duration. A sweep travels once from a start frequency to an end frequency and stops there, which is why the sweep tools have no rate control.

Why is the frequency integrated rather than set directly?

Because phase has to stay continuous. If each sample simply took the current frequency value, the waveform's phase would jump at every change and the discontinuities would spread energy across the spectrum as clicks and splatter. Integrating the frequency into a running phase keeps the signal smooth and the tone clean.

What happens if the deviation is larger than the centre frequency?

The lower edge of the sweep would compute to a negative value, which has no meaning for a frequency. The displayed range clamps its lower end at one hertz so the readout stays sensible, and the useful answer is to reduce the deviation or raise the centre until they make physical sense.

Can I make it sweep upward only?

Not from this tool, because the modulation is a symmetrical sine. Set the rate very low relative to the duration and you will hear one long excursion that behaves much like a single sweep, or use one of the two sweep generators where a one-way glide is the whole point.

How fast can the modulation be?

Up to one hundred cycles per second, at which point the sweeping is fast enough to be heard as a rough buzz around the centre frequency rather than as a moving pitch. At the slow end, a rate of a few cycles per second reads as an obvious rise and fall.

Chirp Generator

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Chirp Generator sweeps a tone's frequency up and down in a smooth sine-shaped cycle, so it rises and falls repeatedly rather than gliding once. Centre frequency, deviation and rate are all adjustable.

What is Chirp Generator?

The sound rises above a centre frequency, falls below it and returns, repeating at the rate you set. Enter a centre, a deviation and a rate along with the level and duration, and generate the file.

What the controls mean:

A centre frequency from one to twenty thousand hertz, defaulting to one thousand.
A deviation up to ten thousand hertz, defaulting to four hundred, which sets how far above and below the centre the tone travels.
A sweep rate from one hundredth of a hertz to one hundred, defaulting to two, which is how many complete up-and-down cycles happen per second.
Duration from a tenth of a second to sixty seconds, defaulting to four.
An amplitude slider from one to one hundred percent, defaulting to eighty.

The synthesis determines the instantaneous frequency of every sample from a sine function of time and then integrates that value into a running phase, which is the only correct way to build a frequency-modulated signal. Computing the waveform directly from the frequency would produce a signal whose phase jumped discontinuously and would therefore splatter energy across the spectrum. Integration keeps the phase continuous, so the result is a clean tone whose pitch moves exactly as described, and the sweep never leaves the band between the centre minus the deviation and the centre plus the deviation. That bounded range is worth noting, because at high deviations the lower edge approaches zero and the readout clamps the displayed lower limit at one hertz rather than printing a negative number. The modulation is entirely periodic, so the file is a repeating cycle of rises and falls rather than a one-way glide, which is the practical difference between a chirp and a sweep. Listening to it is instructive: at a high rate the pitch reads as an unstable flutter around the centre, while at a low rate it reads as a long and obvious rise and fall that repeats for as long as the file runs. The level never changes as the pitch travels, so the tone stays equally loud from one end of its excursion to the other.

What the tool does not offer:

The modulation shape is a sine only, with no triangle, ramp or random option.
The sweep is bounded by the deviation setting, so it cannot rise indefinitely or hold a steady final frequency.
There is no band-limiting concern like the geometric shapes, but extreme settings can push the upper edge above the audible range.
Frequency is swept but the amplitude stays constant, so there is no matching level envelope.
Amplitude is a linear percentage, and the file is mono and capped at sixty seconds.
No phase offset is available for the modulation cycle.

Use it when a tone needs to move continuously and periodically: masking a narrow band by moving through it, producing an attention-getting but not harsh notification, testing how a system tracks a changing pitch, or generating material that will be analysed on a spectrogram, where the shape of the sweep is plainly visible. For a single one-way glide across a wide range, the sweep tone generator and the frequency sweep generator are the tools built for that job.

How to use Chirp Generator

Set the centre frequency you want the tone to hover around.
Choose a deviation to set how far it travels above and below that centre.
Set the sweep rate and the duration, then adjust the amplitude.
Press generate and download the file, checking the readout for the swept range.

When to use Chirp Generator vs related tools

Chirp Generator is the tool for a tone that moves up and down repeatedly, which suits masking, notification and pitch-tracking tests. Sweep Tone Generator makes a single glide from one frequency to another, and Frequency Sweep Generator adds presets and a reverse option for the same one-way job. Where the movement is slow vibrato-like rather than a full sweep, Warble Tone Generator is the equivalent tool for system checks.

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