Beat Frequency

This interactive simulator explores Beat Frequency in Waves & Sound. Two slightly different frequencies creating audible beats. Use the controls to change the scenario; watch the visualization and any graphs or readouts to connect the model with lectures, labs, and homework.

Who it's for: Best once you already know the basic definitions and want to build intuition. Typical context: Waves & Sound.

Key terms

  • beat
  • frequency
  • beat frequency
  • waves
  • sound

How it works

When two tones are close in frequency, their superposition is a carrier at the average frequency modulated by a slowly varying amplitude. The loudness pulses at the beat frequency |f₁−f₂| — you hear ‘wah-wah’ beats. The canvas scrolls time; dashed lines show the envelope.

Key equations

s = 2 cos(πΔf t) sin(2πfₐᵥₑ t),   fₐᵥₑ = (f₁+f₂)/2,   Δf = f₁−f₂
Beat frequency (loudness maxima per second) ≈ |Δf| when amplitudes match.