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Doppler effect calculator

The pitch you hear from a moving siren, horn or train, with the source and listener moving toward or away from each other.

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Frequency you hear 767.1 Hz

How it works

f′ = f × (c ± v_listener) ÷ (c ∓ v_source)

A source moving toward you squeezes its sound waves together, so you hear a higher pitch; moving away stretches them and the pitch drops. That’s the “neee-yowww” of a passing siren. The same happens if you move toward or away from the source, but by a slightly different amount, so both speeds go into the formula. c is the speed of sound, about 343 m/s in air.

  1. Apply the Doppler formula (speeds in m/s) 700 × (343 + 1 × 0) ÷ (343 − 1 × 30) = 767.1 Hz

Printed from rocketcalc.io/physics/doppler-effect