Six Sound Channels Synthesized via the Web Audio API
This tool synthesizes and plays six audio channels in real time using the browser Web Audio API: white noise, pink noise, brown noise, rain, wind, and ocean waves.
Rather than selecting pre-recorded audio files in a player, it generates short monaural waveform buffers inside an AudioContext and loops them with AudioBufferSourceNode instances.
Audio does not play automatically when opening the page; the AudioContext and required nodes are prepared only when the user triggers playback.
Each channel can be toggled on or off independently, allowing multiple channels to sound simultaneously. Instead of a fixed two-layer soundscape, it functions as a flexible mixer enabling any combination of the six available sound sources.
Individual channel GainNode instances connect to a shared master GainNode, which routes audio directly to the device audio output.
Panning controls and user-adjustable high/low equalizers are not provided.
Browsers and operating systems enforce their own restrictions regarding autoplay policies, background execution, power saving, and audio output routing.
If no sound is heard after initiating playback, verify your tab mute state, hardware volume, active output device, and browser audio permissions.
Subtle differences in acoustic timbre and background playback consistency may also emerge across different environments.
Approximation Algorithms for White, Pink, and Brown Noise
White noise is generated by creating a two-second buffer aligned with the AudioContext sample rate and filling each sample with values from Math.random.
Looping this buffer provides continuous noise playback. This architecture relies on a finite-length pseudo-random buffer rather than a cryptographically random source or a calibrated laboratory test signal with certified frequency responses.
Pink noise approximates a frequency distribution where lower frequencies carry greater energy, routing white random numbers through state variables and summing them with fixed filter coefficients.
Brown noise applies first-order integration, adding small white noise variations to the prior sample with attenuation to emphasize deeper low-frequency energy.
Both run as looped two-second pre-rendered buffers. The tool does not evaluate precise spectral roll-offs, sound pressure levels, or compliance with standard testing signals.
Interface descriptions offer practical references for choosing among relative tonal qualities. Perceived timbre varies depending on the frequency response of your speakers or headphones, device audio processing, and listening volume.
For acoustic measurements, equipment calibration, or clinical audiometry requiring standardized output levels, use dedicated calibrated instruments and test signals.
Filter and LFO Synthesis for Rain, Wind, and Waves
The rain channel blends pink noise passed through an 800 Hz low-pass filter with water droplet transients generated by placing short decaying waveforms at random offsets and filtering them through a 1,500 Hz high-pass filter.
This synthesis approximates the sensation of rain through dual generated waveforms rather than field-recorded audio. Parameters for rain intensity, droplet size, or simulated roofing materials are not adjustable.
The wind channel routes pink noise through a band-pass filter with a Q factor of 2.5, using a low-frequency oscillator (LFO) to sweep the center frequency gently over time.
The ocean waves channel directs brown noise through a 300 Hz low-pass filter, utilizing another low-frequency oscillator to modulate output gain periodically.
In both channels, an individual LFO connects to a single parameter. These channels also represent synthetic sound created by combining noise, filtering, and periodic modulation rather than recordings of natural environments.
Filter cutoff frequencies, resonance Q values, and LFO rates and depths remain hard-coded within the implementation. Users can adjust channel toggles and volume levels, while panning, bass, treble, or reverberation parameters cannot be customized.
The design focuses on easily blending diverse ambient textures rather than faithfully modeling natural acoustics.
Signal Routing for Channel Volume, Master Volume, and Muting
Individual channel sliders display values from 0% to 100%, mapped internally to GainNode values between 0 and 1. Setting a slider above 0 activates the corresponding channel, while setting it to 0 silences it.
If a channel is activated with its toggle button while its slider is at 0, volume defaults to 30%. When volume changes during active playback, gain adjusts toward target values across a brief time constant to help reduce abrupt clicks.
All channels sum into the master GainNode. Master volume is likewise a relative scale, and muting temporarily drives the master gain to 0.
Muting does not erase active channel selections or slider settings, allowing previous mix levels to resume upon unmuting. In contrast, the stop button halts and disconnects sound sources and auxiliary nodes, closing the active AudioContext.
Starting playback anew creates a fresh AudioContext and regenerates buffers.
Percentage values shown in the interface do not represent decibels, sound pressure levels, or system output volumes. A setting of 50% yields distinct physical sound levels depending on device hardware, amplification, transducers, and earfit.
Increasing master volume alongside multiple active channels raises combined output; always begin listening at low levels on your device.
5 to 120 Minute Shutoff Timer and Audio Cleanup
The shutoff timer can be configured from 5 to 120 minutes in 5-minute increments. When started, it calculates a scheduled completion timestamp from current system time and the selected duration, checking elapsed time against Date.now() every second while updating remaining time in the interface.
When remaining time reaches zero, standard stop routines trigger, stopping and disconnecting AudioBufferSourceNode and OscillatorNode instances across all channels and closing the AudioContext.
Canceling the timer clears the scheduled stop without stopping active audio playback.
If the browser tab moves to the background or the device enters a lock screen, sleep state, or battery-saver mode, user interface updates and timer callbacks may throttle, or audio processing itself may pause.
Target end times are tracked against clock differences, but timely shutdown and continuous background playback cannot be guaranteed across operating systems.
When strict alarm timing is required, rely on native operating system timers alongside this tool.
Unmounting the component similarly initiates cleanup, canceling timers, stopping sound sources, and terminating the AudioContext.
However, this handling cannot manage events beyond web page control, such as browser terminations or system-level audio driver changes.
If playback behaves unexpectedly, stop the audio and reload the page if necessary.
Unsupported Features and Safe Listening Precautions
This tool operates as an on-demand synthesizer and mixer. It does not support uploading audio files, capturing microphone input, recording, waveform editing, downloading synthesized audio, streaming broadcast, or saving session configurations.
It does not monitor or process user speech or environmental sounds. Independent of network delivery and host website mechanics, all sound synthesis executes inside this component using the Web Audio API.
References to healing or focus in the title and labels describe intended listening ambiance rather than medical or psychological outcomes.
The tool provides no features to evaluate or guarantee improved sleep, enhanced concentration, stress reduction, autonomic regulation, or tinnitus relief.
Tonal preferences vary across individuals, and users should assess whether specific noise profiles suit their needs at comfortable, low volumes.
Avoid masking critical acoustic cues such as emergency sirens, warnings, or approaching vehicles in environments where situational awareness is required.
This tool is unsuitable for headphone use while driving, walking outdoors, or operating machinery. Verify volume levels whenever launching playback, enabling new channels, or switching hardware audio destinations.
Prolonged exposure to loud sound can strain hearing organs. Reduce device volume prior to initiating playback, especially when using earphones or headphones.
Avoid extended continuous listening, take scheduled breaks, and stop audio immediately if you experience discomfort, tinnitus, ear pain, or headaches.
Consult an audiologist or medical professional if you have preexisting hearing concerns before resuming use.