Acoustic problems always require allowing compressibility, since sound waves are compression waves involving changes in pressure and density of the medium through which they propagate.

* Acoustic spectroscopy involves radiated pressure waves.

Acoustic energy is variation in the air pressure that can be represented as sound waves, which are then perceived by the human auditory system as sound.

Acoustic impedance indicates how much sound pressure is generated by the vibration of molecules of a particular acoustic medium at a given frequency.

Acoustic impedance can be expressed in either its constituent units ( pressure per velocity per area ) or in rayls per square meter.

The muffler is engineered as an acoustic soundproofing device designed to reduce the loudness of the sound pressure created by the engine by way of Acoustic quieting.

Acoustic horns convert large pressure variations with a small displacement area into a low pressure variation with a large displacement area and vice versa.

Acoustic analog recording is achieved by a small microphone diaphragm that can detect changes in atmospheric pressure ( acoustic sound waves ) and record them as a graphic representation of the sound waves on a medium such as a phonograph ( in which a stylus senses grooves on a record ).

Sometimes, for the sake of appearance or of the desired " feel " of the instrument, a drum with a trigger will be used as a trigger pad by muffling it so heavily that no significant sound at all is produced, see Electronic drum # Acoustic triggered drum kit.

Acoustic or sound waves travel at speed given by

Acoustic couplers are still used by people travelling in areas of the world where electrical connection to the telephone network is illegal or impractical.

* Acoustic lobe, radiation pattern exhibited by multi-driver loudspeakers

On 26 January 2004, the film Yesspeak premiered in a number of select theatres, which was followed by a closed-circuit live acoustic performance of the group that was released as Yes Acoustic: Guaranteed No Hiss later on.

Adaptive Transform Acoustic Coding ( ATRAC ) is a family of proprietary audio compression algorithms developed by Sony.

* Acoustic keyloggers: Acoustic cryptanalysis can be used to monitor the sound created by someone typing on a computer.

Acoustic harassment devices and acoustic deterrent devices used by aquaculture facilities to scare away marine mammals emit loud and noxious underwater sounds.

* Andrés Segovia by Mark Small ( Acoustic Guitar, November 2010 )

; Acoustic tablets: Early models were described as spark tablets — a small sound generator was mounted in the stylus, and the acoustic signal picked up by two microphones placed near the writing surface.

However, Adaptive Transform Acoustic Coding 3, or ATRAC3, is a separate format developed by Sony )

Also in 1995, Keaggy was voted by Guitar Player Magazine readers as the # 2 Best Acoustic Fingerstyle Guitarist.

In 2008, Keaggy received the Gold Level Award as the " Best Spiritual / Worship Guitarist ", as voted by readers of Acoustic Guitar Magazine, as well as appearing in the form of vocals and lead guitar on the Richard Cummins CD, Moments, which was nominated for " Best Pop / Contemporary Album of the Year " by the Canadian GMA's, Covenant award.

In September 1942 Atanasoff left Iowa State for a wartime assignment as Chief of the Acoustic Division with the Naval Ordnance Laboratory ( NOL ) in Washington, D. C .; no patent application for the ABC was subsequently filed by Iowa State College.

Acoustic pipes are made by various makers and sold under various brands.

* " Rush ", a 2005 song by MYMP on Beyond Acoustic

The 2006 album by the jazz group Acoustic Ladyland, Skinny Grin, features one of his works, Portrait of The Dancer Alexander Sacharoff, as its cover art.

Acoustic enhancement systems help give a more even sound in the hall and prevent " dead spots " in the audience seating area by "... augment a hall's intrinsic acoustic characteristics.

* " Pray " ( Justin Bieber song ), song by Justin Bieber from the album My Worlds Acoustic

In 1996 Willcox released The Acoustic Album on Aardvark Records, featuring strings from Royal Philharmonic Orchestra and produced by Oliver Davis.

Recently completed is a 450-seat concert hall, called the Bramall Music Building, which completes the redbrick semicircle of the Aston Webb building designed by Glenn Howells Architects with venue design by Acoustic Dimensions.

; Stethoscope: Acoustic device for hearing internal sounds including heart sounds.

Acoustic emission ( AE ) is the sound waves produced when a material undergoes stress ( internal change ), as a result of an external force.

Acoustic guitars are several notable subcategories within the acoustic guitar group: classical and flamenco guitars ; steel-string guitars, which include the flat-topped, or " folk ," guitar ; twelve-string guitars ; and the arched-top guitar.

** Surface Acoustic Wave touchscreens, an electronic visual display that can detect the presence and location of a touch within the display area

Acoustic isolation of the performance space was obtained by constructing a building within a building.

Acoustic Solutions to date are the pioneers in this field ; implementing seismic technology within their speaker range the company has produced a cutting edge range of home speaker systems.

Acoustic emissions can be detected in frequency ranges under 1 kHz, and have been reported at frequencies up to 100 MHz, but most released energy within 1 kHz to 1 MHz.

The deviations from this theme are Punk Goes Acoustic and Punk Goes Acoustic 2 ( in which the featured bands recorded acoustic versions of their own songs ); Punk Goes Pop 1, 2, 3 and 4 ; and Punk Goes Classic Rock.

* Acoustic Bootleg: 15 Cover Songs ( 2000 ; cassette version released in 1995 )

Green Carnation's trend of music has continuously become less and less heavy after every release ; from straight forward death metal, to a gothic metal / doom metal / progressive metal sound, to a melancholic hard rock-sounding form of progressive rock and in 2006, went as far as to releasing an entirely acoustic album Acoustic Verses.

The design team for this renovation effort included Westlake Reed Leskosky Architects of Cleveland, Ohio ; McCarty Holsaple McCarty Architects of Knoxville, Tennessee ; Evergreene Studios, Historic Restoration Consultants of New York, New York ; and Acoustic Consultant Kirkegaard Associates of Chicago, Illinois.

* Davis, D & Wickersham, R., " Experiments in the Enhancement of the Artist's Ability to Control His Interface with the Acoustic Environment in Large Halls ", presented at the 51st AES Convention, 13 – 16 May 1975 ; preprint number 1033.

; Acoustic Shagrat

:-- Acoustic guitar, cello, violin ; Lyrics are cryptic, again touching on the coarseness and natural brutality of the human animal.

( Acoustic Guitar ; Piano ; Strings )

Clifton Hyde with Mustapick Acoustic Baritone Guitar ; Brooklyn, New York City 2007

In technology-mediated instruction she developed learning modules such as: " The Business of Space " to promote cultural diversity and global awareness about space and astronomy ; " Astronomy in Paintings, Frescos, and Engravings " on how art has been used to explain the Universe from stars to galaxies ; " Sounds of the Universe: Acoustic Astronomy " to stimulate intellectual curiosity and individual thinking and " Invisible Universe " learning module to explore celestial objects in multi-wavelengths.

; downslope enhancement: Acoustic energy from a source in shallow water changes from a bottom bounce path to a convergence zone or sound channel path as it travels to deeper water and is concentrated down the slope to a receiver in deep water.

; upslope enhancement: Acoustic energy from a source in deep water changes from a convergence zone or sound channel path to a bottom bounce path as the bottom shoals and is concentrated up the slope to a receiver in shallow water.

The SLSS comprised a total of 10 speakers ; 3 x 10 cm tweeters in the front console ( left, right and centre ), 2 x 10 cm door-mounted cones ( left and right ), 2 x tweeters and 2 x cones contained in a single, tube shaped unit mounted on the rear parcel shelf, and a boot fitted ' Acoustic Resonance Woofer ' ( subwoofer ).

* Acoustic at Olympic Studios ( tour-only CD ; reissued for wide release as Rewolf ) ( February 8, 2009 )