Show HN: Tone Generator

3 hours ago

A tone generator produces a single clean sound at a user-selected frequency, from 1 to 20,000 Hz, and operates entirely within a browser without downloads.
Common uses include testing speakers and headphones, checking hearing, tuning instruments, easing tinnitus, teaching sound concepts, and setting up audio gear.
The tool offers four sound shapes (sine, square, sawtooth, triangle), left/right channel control, real-time adjustment, and shareable links that preserve settings across devices.
Choosing the right frequency depends on the target: 20-60 Hz for subwoofers (testing rattles), 200-2 kHz for voice/matching speakers, and above 10 kHz for tweeters and hearing checks; 440 Hz is standard for tuning instruments.
Sine waves are ideal for testing and tuning due to their pure, single-frequency nature, while other shapes add overtones, making them useful for assessing distortion or mimicking synth and string sounds.

Digital sound representation involves sampling analog pressure waves at regular intervals.
Sound frequency (pitch) is measured in hertz (Hz), with human hearing up to ~20,000 Hz.
Pulse Code Modulation (PCM) stores samples as integer values, often 16-bit signed.

Fourier transforms convert signals between time and frequency domains, enabling spectrogram generation.
A square wave can be approximated by summing cosine waves with harmonics, illustrating how Fourier series work.
Real-world audio (e.g., a mouth pop) can be reconstructed using a limited number of cosine components via FFT.

An online tool that changes pronunciation to clearer, native English accents while preserving your voice identity and timbre.
Supports multiple native accents, including American, British, Australian, and others, without altering the original language.
Works with audio or video files (up to 25MB) or allows direct recording via browser; recommended clip length is 5–15 seconds.

PartialString uses finite-difference time-domain (FDTD) to simulate a plucked string by solving the 1D wave equation in real time.
The string is represented as a list of displacements; lower notes require longer strings with more points.
Controls include excitation position and shape (velocity-sensitive), LFO-swept pickup position, adjustable decay time, and piano-like dampers.

The software uses a metronome grid to capture sung pitches and represent them as notes on a staff with vertical beat lines.
It distinguishes between tied notes and repeated notes based on re-attack sensitivity, which analyzes volume dips between same-pitch sounds.
Re-attack sensitivity can be adjusted; higher values split notes more easily, while setting it to 0 forces all into one tied note.

Digital sound representation involves sampling analog pressure waves at regular intervals.
Sound frequency (pitch) is measured in hertz (Hz), with human hearing up to ~20,000 Hz.
Pulse Code Modulation (PCM) stores samples as integer values, often 16-bit signed.

Fourier transforms convert signals between time and frequency domains, enabling spectrogram generation.
A square wave can be approximated by summing cosine waves with harmonics, illustrating how Fourier series work.
Real-world audio (e.g., a mouth pop) can be reconstructed using a limited number of cosine components via FFT.

An online tool that changes pronunciation to clearer, native English accents while preserving your voice identity and timbre.
Supports multiple native accents, including American, British, Australian, and others, without altering the original language.
Works with audio or video files (up to 25MB) or allows direct recording via browser; recommended clip length is 5–15 seconds.

PartialString uses finite-difference time-domain (FDTD) to simulate a plucked string by solving the 1D wave equation in real time.
The string is represented as a list of displacements; lower notes require longer strings with more points.
Controls include excitation position and shape (velocity-sensitive), LFO-swept pickup position, adjustable decay time, and piano-like dampers.

The software uses a metronome grid to capture sung pitches and represent them as notes on a staff with vertical beat lines.
It distinguishes between tied notes and repeated notes based on re-attack sensitivity, which analyzes volume dips between same-pitch sounds.
Re-attack sensitivity can be adjusted; higher values split notes more easily, while setting it to 0 forces all into one tied note.

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