Mic Distance Calculator

Calculate sound level changes with distance using the inverse square law, proximity effect onset, and the 3:1 rule for multi-mic setups.

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How It Works

The inverse square law: SPL drops 6 dB every time you double the distance. SPL = source_SPL - 20·log10(d). The 3:1 rule prevents phase cancellation between multiple mics — the second mic should be at least 3× the distance of the first mic from its source. This ensures leakage is at least 10 dB below the direct signal. Proximity effect: directional mics boost bass frequencies when closer than ~30 cm, up to 6-10 dB at very close range. Critical distance is where direct sound equals reverberant sound.