Science
Sound intensity level
Convert an acoustic intensity and reference intensity into a decibel level.
Calculators / Science / Doppler shift from a moving source
Doppler shift from a moving source calculator
Estimate frequency heard by a stationary observer when a sound source moves toward or away from them.
On this page
Observed frequency1,095.85Hz
Frequency shift95.85Hz
Calculator controls
How to calculate
Estimate frequency heard by a stationary observer when a sound source moves toward or away from them.
Observed frequency = f*c/(c-v) Hz; Frequency shift = f*c/(c-v)-f Hz
Worked example
Emitted frequency (Hz): 1000; Wave speed (m/s): 343; Source approach speed (m/s): 30.
Observed frequency: 1,095.85 Hz; Frequency shift: 95.85 Hz.
Assumptions and limits
Positive source speed means approach; negative means recession. Uses a stationary medium and observer, with source speed below wave speed; excludes shock waves and relativistic effects.
Results are rounded for display; calculations use unrounded values. Read our calculation methodology.
Understanding the result
Estimate frequency heard by a stationary observer when a sound source moves toward or away from them.
When this tool is useful
Observed frequency = f*c/(c-v) Hz; Frequency shift = f*c/(c-v)-f Hz
Understanding your inputs
| Input | What to enter |
|---|---|
| Emitted frequency (Hz) | Enter a number of at least 0 and no more than 1000000000000. |
| Wave speed (m/s) | Enter a number of at least 1e-12 and no more than 1000000000000. |
| Source approach speed (m/s) | Enter a number of at least -1000000000000 and no more than 1000000000000. |
Frequently asked questions
What assumptions does this calculation use?
Positive source speed means approach; negative means recession. Uses a stationary medium and observer, with source speed below wave speed; excludes shock waves and relativistic effects.
How is the result calculated?
Observed frequency = f*c/(c-v) Hz; Frequency shift = f*c/(c-v)-f Hz