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Frequency Generator

Stack up to four Web Audio oscillators and A/B compare two presets to hear how waveforms and frequencies differ.

Your browser does not support the Web Audio API.
A
Preset A
440 Hz sine
Preview
100%
Osc 1

How to use this tool

  1. Pick a waveform and frequency

    Start with preset A. Choose one of the four waveforms (sine, square, triangle, or sawtooth) and drag the logarithmic frequency slider to your target pitch, or type an exact Hz value into the number box. The range runs from 20 Hz at the bottom of human hearing up to 20,000 Hz at the top.

  2. Stack up to four oscillators

    Click Add Oscillator to layer a second, third, or fourth tone. Each oscillator has its own waveform, frequency, volume, and mute toggle. This lets you build chords, octaves, or beat frequencies. The waveform preview draws one lane per oscillator so each tone stays readable.

  3. Turn on A/B compare to switch presets

    Fill in preset B the same way. Toggle A/B Compare on and set a switch interval between 0.5 and 10 seconds. The tool alternates between A and B automatically. Use Swap to flip the two, or click Play A and Play B to jump between them on demand.

  4. Press Play and share the URL

    Hit Play to start audio. All your settings are in the address bar, so copy the URL to share the exact patch. The link opens silent on the other end because browsers block autoplay without a user gesture, so the recipient hits Play themselves.

About this tool

The Frequency Generator is a browser-based tone playground built on the Web Audio API. It plays pure tones from 20 Hz at the floor of human hearing all the way up to 20 kHz at the ceiling, with your choice of sine, square, triangle, or sawtooth waveforms. No upload, no sign in, no plugin. Everything runs locally through your sound card.

Stack up to four oscillators into a preset to build chords, octaves, or beat frequencies, then save a second preset and A/B compare them on a configurable switch interval. Use it to tune by ear, test speakers and headphones for rattles and dead spots, sweep for your personal high-frequency hearing limit, or match a tinnitus pitch to a known reference tone.

Why the frequency slider is logarithmic

Human pitch perception is logarithmic, not linear. Each octave doubles the frequency, so the perceptual distance from 20 to 40 Hz is the same as the distance from 10,000 to 20,000 Hz. A linear slider would cram the entire bottom three octaves into the first few pixels and dedicate the whole upper half to the top octave nobody can hear. A logarithmic slider spreads octaves evenly, so middle A at 440 Hz lands near the center and the bass end is as tweakable as the treble end.

Waveforms and harmonics

A sine wave is the cleanest possible tone, a single pitch with no overtones. A square wave adds odd harmonics and sounds buzzy. A triangle wave has softer odd harmonics and reads as mellow. A sawtooth wave contains both odd and even harmonics and sounds rich, bright, and slightly reedy. The fundamental frequency stays identical across all four at the same Hz value, so swapping waveforms on a single oscillator is the fastest way to hear what harmonics actually do.

When to reach for it

Use it before buying audio gear to check your current speakers or headphones for frequency response humps and dead zones. Use it as a tuning reference when you do not have a tuner handy. Use it to demonstrate beat frequencies in a physics or music class by stacking two oscillators a few Hz apart. And use it for a quick at-home hearing check by sweeping the frequency up until the tone vanishes.

Popular test tone scenarios

Pre-built tone patches with hand-written guides for the most common audio tests.

Subwoofer test
30 + 50 + 60 Hz sines for subwoofer extension and room-mode checks
View details ➜
1 kHz reference
The audio engineering calibration tone at 1000 Hz
View details ➜
Beat frequency
440 + 444 Hz reveals the 4 Hz amplitude wobble
View details ➜

Waveform & pitch comparisons

Hear two waveforms or pitches side by side at the same frequency, with spec tables covering harmonics, RMS, and use cases.

Sine wave vs Square wave
Pure pitch versus the buzzy harmonic stack.
Read comparison ➜
Square wave vs Triangle wave
Buzz versus mellow, both using only odd harmonics.
Read comparison ➜
Sawtooth wave vs Triangle wave
Bright, reedy, full spectrum versus soft, mellow, odd-only.
Read comparison ➜

Frequently asked questions

What is a frequency generator used for?
A frequency generator plays pure audio tones at an exact Hz value. Musicians use it to tune by ear, audio engineers use it to test speakers and headphones for rattles or dead spots, and hearing testers use it to map the upper and lower limits of their hearing. It is also a quick way to expose a tinnitus pitch by matching it to a known tone.
What frequency range can humans hear?
The nominal range is 20 Hz to 20,000 Hz, though most adults top out closer to 15 to 17 kHz after childhood. The lowest tones you feel more than hear. This tool spans the full 20 Hz to 20 kHz range so you can sweep through it and find your own cutoff.
What is the difference between sine, square, triangle, and sawtooth waves?
A sine wave is a single pure pitch with no overtones. A square wave adds odd harmonics and sounds buzzy and hollow. A triangle wave has softer odd harmonics and sounds mellower. A sawtooth wave has both odd and even harmonics and sounds rich and sharp. The fundamental pitch stays the same across all four at a given frequency.
How does A/B compare mode work?
Save two oscillator presets as A and B. With compare on, the tool switches between them at the interval you set, between 0.5 and 10 seconds. You can also swap A and B, or click Play A and Play B to jump between them manually. It is the fastest way to hear how two chords or two waveforms differ.
Why is there a logarithmic frequency slider?
Human hearing is logarithmic. Each octave doubles the frequency, so the gap from 20 to 40 Hz is as wide perceptually as the gap from 10,000 to 20,000 Hz. A linear slider wastes the whole upper half on the top octave. A log slider spreads octaves evenly across the track, so 440 Hz (A4) sits in the middle and the low end is not cramped into one pixel.
Can I share a sound I built with someone else?
Yes. Every change is written to the URL, so the address bar always contains the full patch. Copy the URL and the other person opens the exact same oscillators, waveforms, volumes, and compare settings. The Play button always starts silent so the link does not autoplay the moment it loads.

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