Lecture

Effects of Reflections: Impulse Response and Reflectogram

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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 discusses the effects of reflections on sound, including examples of recordings in different room conditions and how reflections can impact speech and music diffusion. It also covers the concept of reflectogram/echogram, which shows the time series of reflections in a room through impulse response measurements using various sound sources. The lecture further explores impulse response measurements in empty and full rooms, as well as the reverberation time processing in different room types.

Instructor

Hervé Lissek

Expertise Acoustics and audio engineering, Electroacoustics.Room acoustics.Active noise control.Acoustic metamaterials.Assisted reverberation.Psychoacoustics.Sound spatialization Expertise Acoustics and audio engineering, Electroacoustics.Room acoustics.Active noise control.Acoustic metamaterials.Assisted reverberation.Psychoacoustics.Sound spatialization Mission Head of the Acoustic Group at the Laboratory of Wave Engineering LWE. Research topics :Active Electroacoustic Resonators: turning conventional lou

Official source

Related concepts (31)

Acoustics

Acoustics is a branch of physics that deals with the study of mechanical waves in gases, liquids, and solids including topics such as vibration, sound, ultrasound and infrasound. A scientist who works in the field of acoustics is an acoustician while someone working in the field of acoustics technology may be called an acoustical engineer. The application of acoustics is present in almost all aspects of modern society with the most obvious being the audio and noise control industries.

Architectural acoustics

Architectural acoustics (also known as building acoustics) is the science and engineering of achieving a good sound within a building and is a branch of acoustical engineering. The first application of modern scientific methods to architectural acoustics was carried out by the American physicist Wallace Sabine in the Fogg Museum lecture room. He applied his newfound knowledge to the design of Symphony Hall, Boston.

Frequency response

In signal processing and electronics, the frequency response of a system is the quantitative measure of the magnitude and phase of the output as a function of input frequency. The frequency response is widely used in the design and analysis of systems, such as audio and control systems, where they simplify mathematical analysis by converting governing differential equations into algebraic equations.

Absorption (acoustics)

Acoustic absorption refers to the process by which a material, structure, or object takes in sound energy when sound waves are encountered, as opposed to reflecting the energy. Part of the absorbed energy is transformed into heat and part is transmitted through the absorbing body. The energy transformed into heat is said to have been 'lost'. When sound from a loudspeaker collides with the walls of a room part of the sound's energy is reflected, part is transmitted, and part is absorbed into the walls.

Reflection (physics)

Reflection is the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated. Common examples include the reflection of light, sound and water waves. The law of reflection says that for specular reflection (for example at a mirror) the angle at which the wave is incident on the surface equals the angle at which it is reflected. In acoustics, reflection causes echoes and is used in sonar. In geology, it is important in the study of seismic waves.

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