Purpose
Realtime Sound Meter is a free online sound level meter (decibel meter) used to measure environmental noise levels, displaying real-time readings in decibels (dB). It can detect quiet, noisy, or harmful sound levels, help users understand the noise conditions of their environment, and take measures to protect hearing according to reference guidance.
Main capabilities
- Real-time decibel monitoring: Displays environmental noise dB readings in real time through the device microphone.
- Visualization panel: Provides a real-time frequency spectrum and historical charts, showing the context, trends, and sudden peaks of noise.
- PDF report generation: Click "Save Report" to generate a PDF summary locally on the device, including session statistics (minimum, average, maximum), session timestamps, and chart snapshots; audio is not uploaded.
- Sound level guide and safe exposure time table: Provides sound level references for common scenarios (quiet room about 30–40 dB, conversation about 60 dB, traffic about 80 dB), and shows safe exposure times at different decibel levels based on the NIOSH 3 dB exchange rate.
- Quick exposure calculator: Uses 85 dB = 8 hours as the baseline to estimate the maximum daily exposure time according to the 3 dB exchange rate.
- Measurement recommendations and error explanations: Provides a measurement checklist, common sources of error (device differences, automatic gain control, room reflections, distance changes, brief peaks, etc.), and explanations of "what this is/what this is not."
How to use
- Click "Start Measuring" and grant microphone permission.
- View the real-time dB reading; it is recommended to measure continuously for about 30–60 seconds to smooth out sudden noise.
- Click "Stop Measuring" to finish, then click "Save Report" to download the PDF summary.
- Use the data to identify harmful noise sources and protect hearing.
Applicable scenarios
- Home and daily life: Test appliance noise, neighbor noise, bedroom sleep environment, office distractions, quietness of study areas, remote work background sound, workplace compliance or dispute records.
- Audio and entertainment: Calibrate speaker system volume, monitor concert or club sound levels, measure computer fan noise to optimize a quiet PC.
- Health and wellness: Assist with tinnitus management, ensure a quiet baby room environment, correlate stress levels with environmental noise.
Limitations
- The results are reference estimates; differences in device microphones can cause reading offsets, and "Align reading" can be used for calibrationBaseline.
- It cannot replace a calibrated Class 1/2 professional sound level meter and is not suitable for regulatory compliance measurements.
- Calibration depends on the quality of the device microphone; a web tool cannot guarantee 100% accuracy without external hardware calibration.
- Usage recommendations: measure for 30–60 seconds, keep the device stationary and do not cover the microphone, keep a fixed distance from the sound source, avoid wind/airflow, and repeat 3 times to compare the averages.
Privacy and Data Security
All audio processing is performed locally in the browser; audio data is not recorded, stored, or uploaded. The "Save Report" feature generates a PDF file directly on the user's device and uses only the summary statistics of the current session.
