SPRDSenior Physics Research DatabaseDickinson College

All projects

Directional speaker

Beaming audible sound with ultrasound

A parametric array sends an amplitude-modulated ultrasonic beam, and the nonlinearity of air demodulates it into audible sound that stays in a narrow beam. The project covers nonlinear acoustics, a KZK simulation of the beam that predicts the audible sound and its distortion, and measurements of the department's directional speaker with a microphone and audio interface.

Area
Acoustics
Status
A team is working on it now
Length
About 4 weeks, ending in one paper
Advisor
Professor Jackson David
Teams
2026–27
Equipment
The department's directional (parametric) speakerMeasurement microphoneAudio interface (sound card) for recording
Topics
nonlinear acoustics, ultrasound, signal processing, numerical PDEs
A traditional speaker spreads sound to everyone in a wide cone, while a directional speaker sends a narrow beam that only the person under it hears.

Week by week

Each bar is a step; click one to see its goals and how it connects to the others. The red mark is the paper, due at the end of week 4.

  • Theory
  • Simulation
  • Measurement
  • Analysis
  • Writing
  • Paper due
Linear acoustics refresherTheory, week 1Why ultrasound beams are narrowTheory, week 1Nonlinear acoustics and the parametric arrayTheory, week 1The AM drive signalSimulation, week 2The KZK equation, term by termTheory, week 2Measurement setupMeasurement, week 2Solving KZK numericallySimulation, weeks 2–3Beam measurementsMeasurement, week 3Simulation against measurementAnalysis, weeks 3–4Writing the paperWriting, weeks 3–4
  1. week 1Linear acoustics refresherTheory
  2. week 1Why ultrasound beams are narrowTheory
  3. week 1Nonlinear acoustics and the parametric arrayTheory
  4. week 2The AM drive signalSimulation
  5. week 2The KZK equation, term by termTheory
  6. week 2Measurement setupMeasurement
  7. weeks 2–3Solving KZK numericallySimulation
  8. week 3Beam measurementsMeasurement
  9. weeks 3–4Simulation against measurementAnalysis
  10. weeks 3–4Writing the paperWriting
  11. end of week 4Paper duePredict the audible sound from a parametric speaker with a KZK simulation and compare it with measurements of the department's directional speaker.