Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

Sound - Doppler Effect

The doppler effect is the change in sound frequency due to the relative motion between a source and a listener.

The change in frequency of sound due to relative motion between a source and a listener is called the Doppler Effect.

The observed sound frequency for a listener can be expressed as

fr = fs (c + vr) / (c + vs)                                 (1)

where

fr = frequency observed by the receiver (1/s, Hz)

fs = frequency emitted from the source (1/s, Hz)

c = speed of sound (m/s) 

vr = velocity of the receiver relative to the medium - positive if the receiver is moving towards the source(m/s)

vs = velocity of the source relative to the medium - positive if the source is moving away from the receiver (m/s)

Example - A Train passing a Bell

A train with speed 200 km/h (55.6 m/s) passes a bell with sound frequency 1000 Hz. With an air temperature of 20 oC the speed of sound is 343 m/s.

The frequency observed by a passenger in the train before passing the bell can be calculated as

fr = (1000 Hz)((343 m/s) + (55.6 m/s)) / ((343 m/s) + (0 m/s))  

  = 1162 Hz

The frequency observed by the passenger in the train after passing the bell can be calculated as

fr = (1000 Hz) ((343 m/s) + (- 55.6 m/s)) / ((343 m/s) + (0 m/s))  

  = 838 Hz

Doppler Effect Calculator

Calculate the observed frequency with the calculator below:

Sound - Doppler effect - Observed Frequency vs. Relative Velocity and Source FrequencyDownload and print the Doppler Effect Chart

Related Topics

  • Acoustics

    Room acoustics and acoustic properties. decibel A, B and C calculations. Noise Rating (NR) curves. Sound transmission through walls. Calculate sound pressure, sound intensity and sound attenuation.

Related Documents

Search

Search is the most efficient way to navigate the Engineering ToolBox.

Engineering ToolBox - SketchUp Extension - Online 3D modeling!

3D Engineering ToolBox Extension to SketchUp - add parametric components to your SketchUp model

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with older versions of the amazing SketchUp Make and the newer "up to date" SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp Make/Pro from the Extension Warehouse !

Translate this Page

Translate this page to Your Own Language .

About the Engineering ToolBox!

Privacy Policy

We don't collect information from our users. More about

We use a third-party to provide monetization technologies for our site. You can review their privacy and cookie policy here.

You can change your privacy settings by clicking the following button: .

Citation

This page can be cited as

  • The Engineering ToolBox (2012). Sound - Doppler Effect. [online] Available at: https://www.engineeringtoolbox.com/doppler-effect-d_1839.html [Accessed Day Month Year].

Modify the access date according your visit.

3D Engineering ToolBox - draw and model technical applications! 2D Engineering ToolBox - create and share online diagram drawing templates! Engineering ToolBox Apps - mobile online and offline engineering applications!

Unit Converter

















































8.21.8

.