声学是研究媒质中机械波（包括声波、超声波和次声波）的科学，研究范围包括声波的产生，接收，转换和声波的各种效应。同时声学测量技术是一种重要的测量技术，有着广泛的应用。

最简单的声学就是声音的产生和传播，这也是声学研究的基础。

有规律的悦耳声音叫乐音，没有规律的刺耳声音叫噪音。 响度、音调和音色是决定乐音特征的三个因素。

另外，有许多声音是正常人的耳朵听不到的。因为声波的频率范围很宽，由10Hz到10Hz，但正常人的耳朵只能听到20Hz到20000Hz之间的声音。通常把高于20000Hz的声音称为超声波，低于20Hz的声音称为次声波，在20Hz到20000Hz之间的声音称为可闻声。

Acoustics is the interdisciplinary science that deals with the study of all 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.