An audio format is a medium for sound recording and reproduction. The term is applied to both the physical recording media and the recording formats of the audio content—in computer science it is often limited to the audio file format, but its wider use usually refers to the physical method used to store the data.
Note on the use of analog compared to digital in this list; the definition of digital used here for early formats is that which is represented using discrete values rather than fluctuating variables. A piano roll is digital as it has discrete values, that being a hole for each key, unlike a phonograph record which is analog with a fluctuating groove.
Music is recorded and distributed using a variety of audio formats, some of which store additional information.
A Dictaphone cylinder for voice recordingAnalog, the Ediphone and subsequent wax cylinders used in Edison's other product lines continued to be sold up until 1929 when the Edison Manufacturing Company folded.
1894
Pathé cylinder
The vertical-groove pathé cylinderMechanical analog; vertical grooves, vertical stylus motion
Edison's "gold moulded" black wax cylinder recordMechanical analog; vertical groove, horizontal stylus motion - made from hard black wax - 160rpm standard - 100 threads per inch
Indestructible Record cylinder, vertical groove. Constructed of black celluloid on a cardboard core with metal bands at each endMechanical analog; vertical groove, vertical stylus motion - made from black celluloid with cardboard and inner metal bands
The Edison "Amberol" cylinder record, vertical grooveMechanical analog; vertical groove, vertical stylus motion - made from hard black wax - 160rpm standard - 200 threads per inch
The Edison vertical-groove "diamond disc"Mechanical analog; vertical groove, vertical stylus motion - made from Bakelite or china clay
Blue Amberol cylinder record
The Edison vertical-groove "Blue Amberol" cylinderMechanical analog; vertical groove, vertical stylus motion - made from blue celluloid with plaster of paris core - 160rpm standard - 200 threads per inch
Studio master tape reelAnalog; magnetization; AC "bias" dramatically increases linearity/fidelity, tape speed at 30 ips, later 15 ips and other refined speeds: 7+1⁄2 ips, 3+3⁄4 ips, 1+7⁄8 ips
Mechanical analog; electrically cut from amplified microphone signal, high fidelity sound, lateral or vertical groove, horizontal or vertical stylus motion, most discs 16" at 33+1⁄3 rpm
Green, vertical groove Sound Scriber disks Mechanical Analog; vertical groove, 4–6 inch discs, it recorded sound by pressing grooves into soft vinyl discs
Analog, medium consisting of a thin, plastic belt 3.5" wide that was placed on a cylinder and rotated like a tank tread, developed by the Dictaphone company in 1947
Analog, with preemphasis and other equalization techniques (LP, RIAA); lateral groove, horizontal stylus motion; discs 7", 10" and 12" at 33+1⁄3 rpm, 1st LP Columbia ML 4001 Milstein, Mendelssohn Violin Concerto
A stand-alone Tefifon player with cartridge loadedElectro-mechanical analog, vinyl belt housed in a cassette, used an embossing technique using a stylus to imprint the information, was the first thing to resemble a modern audio cassette
Minifon cassetteAnalog, magnetic wire on reel, 30 cm/s or about 11.8 ips was quickly adopted by many governments as being the ultimate "spy" recorder of its day
An early stereo record labelAnalog, with pre-emphasis and other equalization techniques. Combination lateral/vertical stylus motion with each channel encoded 45 degrees to the vertical
Dictet
Cassette for the Dictaphone Dictet dictation machineAnalog, 1⁄4 tape, 2.48 in/s, (3" reels housed 5.875 × 3 × .4375 inch cassette), developed by the Dictaphone Corp
The cassette format created by RCAAnalog, 1⁄4 inch wide tape (stereo & mono), 3+3⁄4 in/s & 1.875 in/s, one of the first attempts to offer reel-to-reel tape recording quality in a convenient format for the consumer market
The cartridge known as a "Fidelipac"Analog, 1⁄4 inch wide tape in cartridge, 7+1⁄2 in/s & 15 in/s, Introduced in 1959 by Collins Radio, the cart tape format was designed for use by radio broadcasters to play commercials, bumpers and announcements
The micro pack recording system, intended for dictation1⁄4 inch wide tape housed in a transparent cartridge measuring 2.6 × 2.9 × 1.9 inches, tape was stored on two reels residing atop one another, keeping the cartridge compact
A cartridge format for embedding and easy handling usual 3-inch-tape-reels with 1⁄4 inch tape, compatible to reel-to-reel audio recording in 3+3⁄4 ips.
DC-International cassetteAnalog cassette format introduced by Grundig, Telefunken and Blaupunkt: 120 × 77 × 12 mm cassette with 1⁄4 inch wide tape run at 5.08 cm per second.
A comparison of sizes for the Microcassette and Minicassette Analog, 1⁄8 inch wide tape, used generally for note taking, mostly mono, some stereo (developed in the early '80s). 2.4 cm/s or 1.2 cm/s
This audio format famously caused controversy among recording companies when released due to the potential of perfect digital copies to increase piracy[2]
A Digital Compact CassetteDigital, 1⁄8 inch wide tape, 1+7⁄8 in/s, introduced by Philips and Matsushita in late 1992, marketed as the successor to the standard analog compact cassette
^Demetris, Jordan (1990-01-01). "The challenge of introducing digital audio tape technology into consumer markets". Technology in Society. 12 (1): 91–100. doi:10.1016/0160-791X(90)90031-7. ISSN0160-791X.