About Sound Generator

Design principles

• One page per job. Each tool does one thing and does it fully. The tone generator makes a tone; the sweep generator makes a sweep. Nothing is hidden behind a menu of modes.
• Exact numbers. Every readout is the real figure: frequency in hertz, level in decibels, duration in milliseconds, wavelength in metres. No rounded marketing figures.
• No accounts. Nothing to sign up for and nothing to log in to. Every setting lives in the URL, so a link is also a preset.
• No ads. No advertising, no sponsorship and no affiliate links. There is nothing on the page competing with the tool.
• Works offline. Audio is generated locally, so once a page has loaded it keeps working with no network connection.

How it works

Every sound is built with the Web Audio API, the audio engine built into your browser. A short script creates an oscillator, a noise source or a sweep, routes it through a master gain and a safety limiter, and connects it to your output device. Nothing is fetched, streamed or rendered on a server.

The site is a static set of pages. There is no application framework running in the browser, no server rendering and no database. Everything you see is generated at build time and shipped as plain HTML, CSS and a little JavaScript.

The offline WAV export

When you save a tone as a WAV file, the browser renders the signal offline with an OfflineAudioContext, the same maths as the live signal but faster than real time, then encodes the result as 16-bit PCM and hands it to your browser as a download. The file is built on your device. Nothing is uploaded to produce it.

The limiter and the master level

Every signal passes through one shared master gain and one shared limiter. The master gain is the slider in the header; it sets the output level for the whole site and is remembered between visits. The limiter is a safety net that catches signals that would otherwise clip in the digital domain. It is not a mixing tool, and it does not protect your ears: only a sensible level does that.

What the tools can and cannot tell you

These are signal generators and simple measurement aids, not calibrated instruments. Be clear about the limits.

• No medical diagnosis. The hearing test steps through frequencies and logs what you report. It cannot measure hearing thresholds, cannot account for the level your device actually produces, and is not a substitute for an audiologist.
• Your playback device is the real limit. Built-in laptop speakers cannot reproduce 40 Hz. Most headphones roll off above 16 kHz. If you cannot hear a tone, it may be the speaker, not your ear.
• kHz limits come from the sample rate. The browser runs at its own sample rate, usually 44.1 or 48 kHz. That sets a hard ceiling at the Nyquist frequency, half the sample rate, above which no correct signal can be produced.
• Browser mixers can resample. Your operating system or a Bluetooth codec may resample or compress the audio before it reaches the speaker. Frequency accuracy is preserved, but absolute level and the very highest frequencies may not be.
• Frequency is precise, level is not. The oscillator frequency is exact to the accuracy of your sound card clock, normally better than 0.01 %. The level you hear depends on the whole chain and cannot be read from this site.

Who it is for

• Musicians tuning instruments against a reference pitch or checking a note by ear.
• Engineers and technicians testing speakers, drivers, crossovers and room response with sweeps and noise.
• Teachers demonstrating interference, beats and harmonics, with the physics on the acoustic theory page.
• Installers checking telephone and DTMF signalling with the DTMF generator and time pips.
• Students learning what a frequency, a wavelength or a decibel actually sounds like.
• Anyone who needs to test a speaker, a set of headphones or a hearing range.

Build note

The site is built with Astro and Tailwind CSS and deployed as static files. There are no accounts, no advertising, no cookie banner and no behavioural tracking. Every page is served from this domain; the one exception is Google Analytics, which measures page views in aggregate so that whoever pays for the hosting can see which tools are worth keeping. It is loaded in production builds only, it is skipped entirely if your browser sends Do Not Track or Global Privacy Control, and the privacy policy describes exactly what it does and how to block it.

Contact

Questions, bug reports and corrections are welcome. Write to [email protected]. The address is also listed in plain text as [email protected].

How your data is handled is set out in the privacy policy.

Every tool on the site, grouped by category. This doubles as a full index of the pages that generate sound.