The 3-Step Audio Measurement Pipeline
Real Decibel Meter utilizes the browser's built-in Web Audio API to capture, analyze, and render sound intensity instantly.
1. Microphone Input Capture
When you click "Start Measuring", your browser requests standard microphone permissions via navigator.mediaDevices.getUserMedia. Audio input is captured uncompressed in real-time.
2. RMS & Frequency DSP
The continuous audio stream is passed through an audio node analyzer. Root Mean Square (RMS) voltage energy and Fast Fourier Transform (FFT) frequency spectrums are calculated at 60 FPS.
3. dB Mapping & Ballistics
RMS values are converted to decibels using logarithmic scaling: dB = 20 * log10(RMS) + Offset. Exponential decay ballistics provide smooth, jitter-free needle animation.
Understanding Decibel (dB) Mathematics
The decibel is not an absolute physical unit like meters or kilograms; rather, it is a logarithmic ratio comparing the power or intensity of a sound to a reference level (standard human threshold of hearing, 20 micropascals at 1 kHz).
Key Decibel Scaling Rules:
- +3 dB Increase: Doubles the acoustic sound energy / sound power.
- +10 dB Increase: Represents a 10-fold increase in acoustic energy and sounds approximately twice as loud to the human ear.
- +20 dB Increase: Represents a 100-fold increase in acoustic energy and sounds 4 times louder.
All audio calculations take place purely within your computer or smartphone browser memory. No microphone recordings or voice packets are ever recorded, saved to disk, or transmitted over any network.