Acoustic Doppler Effect Vector Calculator

The Doppler effect is the perceived pitch change that occurs when a wave source and receiver are in relative motion.

Vehicles passing a roadside observer exhibit a characteristic pitch drop from high to low as the approach angle sweeps past 90 degrees.

Only the velocity component along the direct line of sight between source and observer contributes to wave compression.

When approaching (theta < 90 deg), perceived frequency is shifted higher.

When receding (theta > 90 deg), line-of-sight velocity is negative, shifting pitch lower.

Observed frequency indicates the exact pitch heard by the receiver.

Frequency shift Delta_f shows the magnitude of chromatic change.

Source Mach number reveals how close the vehicle is to sonic shock wave generation.

• Approach angle: Head-on (0 deg) produces maximum upward shift; perpendicular (90 deg) produces zero shift.
• Ambient temperature: Cooler air reduces speed of sound c, amplifying the Doppler shift percentage.
• Wind velocity: Ambient wind currents alter wave propagation speeds relative to ground observers.

• Acoustic tracking, emergency siren design, and radar/sonar velocity measurement algorithms.
• Acoustic noise assessments for high-speed rail corridors and airport flyover zones.

• Assumes constant velocity vector in a non-turbulent, homogeneous medium.
• Subsonic speeds only (v_los must be strictly below speed of sound).