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Aluminium oxynitride (marketed under the name ALON by Surmet Corporation [3]) is a transparent ceramic composed of aluminium, oxygen and nitrogen.Aluminium oxynitride is optically transparent (≥80% for 2 mm thickness) in the near-ultraviolet, visible, and mid-wave-infrared regions of the electromagnetic spectrum.
A micro perforated plate (MPP) is a device used to absorb sound, reducing its intensity. It consists of a thin flat plate, made from one of several different materials, with small holes punched in it. An MPP offers an alternative to traditional sound absorbers made from porous materials.
A crystallophone is a musical instrument that produces sound from glass. One of the best known crystallophones is the glass harmonica, a set of rotating glass bowls which produce eerie, clear tones when rubbed with a wet finger. Musical glasses, the glass harp, were documented in Persia in the 14th century. [1]
They consist of an aluminum disc with a coating of nitrocellulose lacquer with acetone added to make a varnish. Glass was often used for the substrate during World War II, when aluminum was in short supply. [2] [3] The production process results in a disc that is different in several ways from the vinyl records sold to customers at retail. Most ...
Phonograph cylinders (also referred to as Edison cylinders after its creator Thomas Edison) are the earliest commercial medium for recording and reproducing sound.Commonly known simply as "records" in their heyday (c. 1896–1916), a name which has been passed on to their disc-shaped successor, these hollow cylindrical objects have an audio recording engraved on the outside surface which can ...
An acoustic metamaterial, sonic crystal, or phononic crystal is a material designed to manipulate sound waves or phonons in gases, liquids, and solids (crystal lattices).By carefully controlling properties such as the bulk modulus β, density ρ, and chirality, these materials can be tailored to interact with sound in specific ways, such as transmitting, trapping, or amplifying waves at ...
Cups or wine glasses are filled with varying levels of water. The glasses may either be struck with a dampened stick to produce a percussive sound, or a player may moisten their fingers and rub the rims of the glasses to produce a sound. Robert Tiso playing a glass harp: Glass harmonica (glass armonica, glass harmonium, bowl organ ...
In 2005, the best anechoic chamber measured at −9.4 dBA. [2] In 2015, an anechoic chamber on the campus of Microsoft broke the world record with a measurement of −20.6 dBA. [ 3 ] The human ear can typically detect sounds above 0 dBA, so a human in such a chamber would perceive the surroundings as devoid of sound.