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For Educators · Sound Levels (dB)

Sound Levels (dB) for a Doppler siren

Built for educators teaching it to a class. Drop a live demo into a lecture or assign it as a shareable link — no lab installs. Simulate a Doppler siren live below — adjust the inputs and watch it respond, right in your browser.

Sound Levels (dB SPL)Live

adding & spreading loudness

Controls

Presets

Level per source at 1 m (dB)

Number of sources

Distance (m)

Decibels are logarithmic, so loudness does not add the way you expect: two identical sources are only 3 dB louder than one, and ten are 10 dB. Meanwhile a point source drops 6 dB every time the distance doubles (the inverse-square law). Sustained exposure above 85 dB risks hearing damage.

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Data Inspector

Combined at 1 m85.0 dB

At 4 m73.0 dB

Doubling sources+3 dB

Risksafe range

Governing equation

L = 85.0 - 20 lo g_{10} (4) = 73.0 dB

Reading this result: A single source falls from 85 dB to 73 dB across 4 m — about 6 dB lost each time the distance doubles.

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Frequently asked questions

Is this good for educators?: Yes — this version of "Sound Levels (dB) for a Doppler siren" is framed for educators teaching it to a class. Drop a live demo into a lecture or assign it as a shareable link — no lab installs.
Do I need to install anything?: No. It runs in any modern browser, free, with no account required.