Project Purpose
We built the Real-Time Sound Meter so anyone could check ambient noise instantly — free, private, and without installing a standalone app or buying a dedicated meter.
How We Compute Decibels (dB SPL)
Your browser handles the audio itself through the native Web Audio API, converting the incoming analog signal into digital PCM buffers in real time.
1. Root Mean Square (RMS) Computation
To get a meaningful energy reading across each buffer of samples, we compute the Root Mean Square:
RMS = sqrt( (1 / N) * Σ (sample_i)^2 ) 2. Mapping Decibels Full Scale (dBFS) to SPL
From there, we convert dBFS into an estimated Sound Pressure Level using an empirical calibration offset:
dB SPL = 20 * log10(RMS) + Calibration Offset (C ≈ 90–95 dB) Privacy Assurance
All of this happens in memory, entirely client-side, in your browser's JavaScript. Your microphone audio is never recorded, stored, or sent anywhere — full stop.