The listed subdisciplines are loosely based on the PACS (
Physics and Astronomy Classification Scheme) coding used by the
Acoustical Society of America.
Aeroacoustics Aeroacoustics is concerned with how noise is generated by the movement of air, for instance via turbulence, and how sound propagates through the fluid air. Aeroacoustics plays an important role in understanding how noise is generated by
aircraft and
wind turbines, as well as exploring how
wind instruments work.
Audio signal processing Audio signal processing is the electronic manipulation of audio signals using
analog and
digital signal processing. It is done for a variety of reasons, including: • to enhance a sound, e.g. by applying an audio effect such as
reverberation; • to remove unwanted noises from a signal, e.g.
echo cancellation in
internet voice calls; • to compress an audio signal to allow efficient transmission, e.g. perceptual coding in
MP3 and
Opus • to understand the content of the signal, e.g. identification of music tracks via
music information retrieval.
Audio engineers develop and use audio signal processing algorithms.
Architectural acoustics was meticulously designed for superior acoustical qualities. concert hall is covered with
perforated metal panels Architectural acoustics (also known as
building acoustics) is the science and engineering of achieving a good sound within a building. Architectural acoustics can be about achieving good speech intelligibility in a theatre, restaurant or railway station, enhancing the quality of music in a concert hall or recording studio, or suppressing noise to make offices and homes more productive and pleasant places to work and live. Architectural acoustic design is usually done by acoustic consultants.
Bioacoustics Bioacoustics concerns the scientific study of sound production and hearing in animals. It can include: acoustic communication and associated animal behavior and evolution of species; how sound is produced by animals; the auditory mechanisms and neurophysiology of animals; the use of sound to monitor animal populations, and the effect of man-made noise on animals.
Electroacoustics This branch of acoustic engineering deals with the design of headphones,
microphones,
loudspeakers, sound systems, sound reproduction, and recording. There has been a rapid increase in the use of portable electronic devices which can reproduce sound and rely on electroacoustic engineering, e.g.
mobile phones,
portable media players, and
tablet computers. The term "electroacoustics" is also used to describe a set of electrokinetic effects that occur in heterogeneous liquids under influence of ultrasound.
Environmental noise , acoustic analysis is critical to creating the best experience for the audience and the performers. Environmental acoustics is concerned with the control of noise and vibrations caused by traffic, aircraft, industrial equipment, recreational activities and anything else that might be considered a nuisance.
Musical acoustics Musical acoustics is concerned with researching and describing the physics of music and its perception – how
sounds employed as
music work. This includes: the function and design of
musical instruments including electronic
synthesizers; the human voice (the
physics and
neurophysiology of
singing); computer analysis of music and composition; the clinical use of music in music therapy, and the perception and cognition of
music.
Noise control Noise control is a set of strategies to reduce
noise pollution by reducing noise at its source, by inhibiting sound propagation using
noise barriers or similar, or by the use of ear protection (
earmuffs or
earplugs). Control at the source is the most cost-effective way of providing noise control. Noise control engineering applied to cars and trucks is known as
noise, vibration, and harshness (NVH). Other techniques to reduce product noise include
vibration isolation, application of acoustic absorbent and acoustic enclosures. Acoustical engineering can go beyond noise control to look at what is the best sound for a product, for instance, manipulating the sound of door closures on
automobiles.
Psychoacoustics Psychoacoustics tries to explain how humans respond to what they hear, whether that is an annoying noise or beautiful music. In many branches of acoustic engineering, a human listener is a final arbitrator as to whether a design is successful, for instance, whether
sound localisation works in a
surround sound system. "Psychoacoustics seeks to reconcile acoustical stimuli and all the scientific, objective, and physical properties that surround them, with the physiological and psychological responses evoked by them."
Ultrasonics Ultrasonics deals with sound waves in solids, liquids and gases at frequencies too high to be heard by the average person. Specialist areas include medical ultrasonics (including
medical ultrasonography),
sonochemistry,
nondestructive testing, material characterisation and
underwater acoustics (
sonar).
Underwater acoustics Underwater acoustics is the scientific study of sound in water. It is concerned with both natural and man-made sound and its generation underwater; how it propagates, and the perception of the sound by animals. Applications include
sonar to locate submerged objects such as
submarines, underwater communication by animals, observation of sea temperatures for climate change monitoring, and marine biology.
Vibration and dynamics Acoustic engineers working on vibration study the motions and interactions of mechanical systems with their environments, including measurement, analysis and control. This might include:
ground vibrations from railways and construction;
vibration isolation to reduce noise getting into recording studios; studying the effects of vibration on humans (
vibration white finger);
vibration control to protect a bridge from
earthquakes, or modelling the propagation of structure-borne sound through buildings. ==Fundamental science==