Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

Sound Radiation: The Dipole

In course

EE-548: Audio engineering

This lecture is oriented towards the study of audio engineering, room acoustics, sound propagation, and sound radiation from sources and acoustic antennas. The learning outcomes will be the techniques for microphones and loudspeaker design, as well as room ...

Description

This lecture covers the theory and simulation of sound radiation from a dipole source, including the superposition principle, near and far field behavior, directivity patterns, and properties of the dipole field. The presentation also discusses the computation of acoustic pressure and sound pressure level in different domains, as well as the impact of distance and frequency on the radiation pattern.

Instructor

Hervé Lissek

Official source

Related concepts (19)

Electromagnetic field

An electromagnetic field (also EM field or EMF) is a classical (i.e. non-quantum) field produced by moving electric charges. It is the field described by classical electrodynamics (a classical field theory) and is the classical counterpart to the quantized electromagnetic field tensor in quantum electrodynamics (a quantum field theory). The electromagnetic field propagates at the speed of light (in fact, this field can be identified as light) and interacts with charges and currents.

Near and far field

The near field and far field are regions of the electromagnetic (EM) field around an object, such as a transmitting antenna, or the result of radiation scattering off an object. Non-radiative near-field behaviors dominate close to the antenna or scattering object, while electromagnetic radiation far-field behaviors dominate at greater distances. Far-field E (electric) and B (magnetic) field strength decreases as the distance from the source increases, resulting in an inverse-square law for the radiated power intensity of electromagnetic radiation.

Sound pressure

Sound pressure or acoustic pressure is the local pressure deviation from the ambient (average or equilibrium) atmospheric pressure, caused by a sound wave. In air, sound pressure can be measured using a microphone, and in water with a hydrophone. The SI unit of sound pressure is the pascal (Pa). A sound wave in a transmission medium causes a deviation (sound pressure, a dynamic pressure) in the local ambient pressure, a static pressure. Sound pressure, denoted p, is defined by where ptotal is the total pressure, pstat is the static pressure.

Electric field

An electric field (sometimes E-field) is the physical field that surrounds electrically charged particles and exerts force on all other charged particles in the field, either attracting or repelling them. It also refers to the physical field for a system of charged particles. Electric fields originate from electric charges and time-varying electric currents. Electric fields and magnetic fields are both manifestations of the electromagnetic field, one of the four fundamental interactions (also called forces) of nature.

Simulation

A simulation is the imitation of the operation of a real-world process or system over time. Simulations require the use of models; the model represents the key characteristics or behaviors of the selected system or process, whereas the simulation represents the evolution of the model over time. Often, computers are used to execute the simulation. Simulation is used in many contexts, such as simulation of technology for performance tuning or optimizing, safety engineering, testing, training, education, and video games.

Related lectures (61)

Second Maxwell's equation: Magnetic dipole

Covers Maxwell's equations, magnetic dipoles, vector potential, torque, and field patterns.

Magnetic Induction

Explains magnetic induction, force on a dipole, torque, and applications in macroscopic systems.

Magnetic Fields and Currents

Explores magnetic fields, currents, Biot-Savart law, Ampère's law, and magnetic dipoles.

Monopole: Acoustic Pressure Simulation in COMSOL Multiphysics

Explains the simulation of acoustic pressure around a monopole using COMSOL Multiphysics.

Radiation of Combined Sources: Acoustic Principles and Directivity