Although fluid is sometimes used as an alternative word for liquid, air is treated as a fluid in the field of fluid mechanics. Objects moving through air encounter forces and experience conditions similar to objects traveling through liquids.
Audio communication is any form of transmission that is based on hearing. Audio communicative forms are found in such platforms as audio books, television, movie soundtracks and music records.
Some types of audio systems include Hi-Fi music systems, wireless music systems and MP3 docking systems. Other examples include home theater systems, portable music systems, and CD or radio cassette players.
An audio converter is hardware or software capable of decoding or encoding a digital data stream of audio. Analog-to-digital converters receive a continuous signal, usually voltage, and convert it into a digital number to estimate its amplitude.
An audio equalizer, or EQ, alters sound by adding to or reducing frequencies within a signal. Treble and bass controls on audio equipment are two types of equalizers that adjust high and low frequencies, respectively.
According to Reference.com, "fluid pressure" is defined as the pressure exerted by a fluid at a given depth. The weight of the liquid acting on a unit area combined with pressure acting on the surface of the liquid determines the amount of liquid pressure.
Air is a fluid because the force needed to deform it depends on how fast it is deformed, not on how much it is deformed. This differs from a solid, where the force needed to deform it remains the same whether it is done quickly or slowly.