Phonograph record in the context of A-side and B-side

The Voyager Golden Records are two identical phonograph records, with one copy aboard each of the two Voyager spacecraft launched in 1977. The records contain sounds and data to reconstruct raster scan images selected to portray the diversity of life and culture on Earth, and are intended for any intelligent extraterrestrial life form who may find them. The records are a time capsule.

Although neither Voyager spacecraft is heading toward any particular star, Voyager 1 will pass within 1.6 light-years' distance of the star Gliese 445, currently in the constellation Camelopardalis, in about 40,000 years.

Plagioclase (/ˈplædʒ(i)əˌkleɪs, ˈpleɪdʒ-, -ˌkleɪz/ PLAJ-(ee)-ə-klayss, PLAYJ-, -⁠klayz) is a series of tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continuous solid solution series, more properly known as the plagioclase feldspar series. This was first shown by the German mineralogist Johann Friedrich Christian Hessel (1796–1872) in 1826. The series ranges from albite to anorthite endmembers (with respective compositions NaAlSi₃O₈ to CaAl₂Si₂O₈), where sodium and calcium atoms can substitute for each other in the mineral's crystal lattice structure. Plagioclase in hand samples is often identified by its polysynthetic crystal twinning or "record-groove" effect.

Plagioclase is a major constituent mineral in Earth's crust and is consequently an important diagnostic tool in petrology for identifying the composition, origin and evolution of igneous rocks. Plagioclase is also a major constituent of rock in the highlands of the Moon. Analysis of thermal emission spectra from the surface of Mars suggests that plagioclase is the most abundant mineral in the crust of Mars.

A phonograph, later called a gramophone, and since the 1940s a record player, or more recently a turntable, is a device for the mechanical and analogue reproduction of sound.

The sound vibration waveforms are recorded as corresponding physical deviations of a helical or spiral groove engraved, etched, incised, or impressed into the surface of a rotating cylinder or disc, called a record. To recreate the sound, the surface is similarly rotated while a playback stylus traces the groove and is therefore vibrated by it, faintly reproducing the recorded sound. In early acoustic phonographs, the stylus vibrated a diaphragm that produced sound waves coupled to the open air through a flaring horn, or directly to the listener's ears through stethoscope-type earphones.

Sound-on-film is a class of sound film processes where the sound accompanying a picture is recorded on photographic film, usually, but not always, the same strip of film carrying the picture. Sound-on-film processes can either record an analog sound track or digital sound track, and may record the signal either optically or magnetically. Earlier technologies were sound-on-disc, meaning the film's soundtrack would be on a separate phonograph record.

Data storage is the recording (storing) of information (data) in a storage medium. Handwriting, phonographic recording, magnetic tape, and optical discs are all examples of storage media. Biological molecules such as RNA and DNA are considered by some as data storage. Recording may be accomplished with virtually any form of energy. Electronic data storage requires electrical power to store and retrieve data.

Data storage in a digital, machine-readable medium is sometimes called digital data. Computer data storage is one of the core functions of a general-purpose computer. Electronic documents can be stored in much less space than paper documents. Barcodes and magnetic ink character recognition (MICR) are two ways of recording machine-readable data on paper.

A slipcase is a five-sided box, usually made of high-quality cardboard, into which binders, books or book sets are slipped for protection, leaving the spine exposed. Special editions of books are often slipcased for a stylish appearance when placed on a bookshelf. A few publishers, such as the Folio Society, publish nearly all their books in slipcases.

Protective slipcases have been issued for records, cassettes, 8-track tapes, film, video cassettes, compact discs, DVDs and even toys instead of or in addition to the more common jewel cases or keep case, and may be chosen for aesthetic or economic reasons. Larger slipcases that are designed to house one or more items are often used in packaging for special edition releases or box sets.

An album is a collection of audio recordings (e.g., music) issued on a medium such as compact disc (CD), vinyl (record), audio tape (like 8-track or cassette), or digital. Albums of recorded sound were developed in the early 20th century as individual 78 rpm records (78s) collected in a bound book resembling a photo album; this format evolved after 1948 into single vinyl long-playing (LP) records played at 33+1⁄3 rpm.

The album was the dominant form of recorded music expression and consumption from the mid-1960s to the early 21st century, a period known as the album era. Vinyl LPs are still issued, though album sales in the 21st-century have mostly focused on CD and MP3 formats. The 8-track tape was the first tape format widely used alongside vinyl from 1965 until being phased out by 1983, being gradually supplanted by the cassette tape throughout the 1970s and early 1980s; the popularity of the cassette reached its peak during the late 1980s before sharply declining during the 1990s. The cassette had largely disappeared by the first decade of the 2000s.

Vernacular music is ordinary, everyday music such as popular and folk music. It is defined partly in terms of its accessibility, standing in contrast to art music. Vernacular music may overlap with non-vernacular, particular in the context of musical commerce, and is often informed by the developments of non-vernacular traditions.

The sales of phonograph records played a dominant role in spreading a cultural taste for popular and vernacular music styles.

A disc jockey, more commonly abbreviated as DJ, is a person who plays recorded music for an audience. Types of DJs include radio DJs (who host programs on music radio stations), club DJs (who work at nightclubs or music festivals), mobile DJs (who are hired to work at public and private events such as weddings, parties, or festivals), and turntablists (who use record players, usually turntables, to manipulate sounds on phonograph records). Originally, the "disc" in "disc jockey" referred to shellac and later vinyl records, but nowadays DJ is used as an all-encompassing term to also describe persons who mix music from other recording media such as cassettes, CDs or digital audio files on a CDJ, controller, or even a laptop. DJs may adopt the title "DJ" in front of their real names, adopted pseudonyms, or stage names.

DJs commonly use audio equipment that can play at least two sources of recorded music simultaneously. This enables them to blend tracks together to create transitions between recordings and develop unique mixes of songs. This can involve aligning the beats of the music sources so their rhythms and tempos do not clash when played together and enable a smooth transition from one song to another. DJs often use specialized DJ mixers, small audio mixers with crossfader and cue functions to blend or transition from one song to another. Mixers are also used to pre-listen to sources of recorded music in headphones and adjust upcoming tracks to mix with currently playing music. DJ software can be used with a DJ controller device to mix audio files on a computer instead of a console mixer. DJs may also use a microphone to speak to the audience; effects units such as reverb to create sound effects and electronic musical instruments such as drum machines and synthesizers.

An entertainment center (or centre), also known as an entertainment complex or a home entertainment center, is a piece of furniture designed to house consumer electronic appliances and components. It is sometimes a large cabinet with an exterior styled to appear like upscale furniture and an interior dedicated to electronic gear, such as home audio, television sets and video game equipment.

Antique or modern reproduction armoires or standing cabinets are used for entertainment centers, as are shelves and shelving systems. Part of the purpose of an entertainment center is to neatly house the many wires and cables that are associated with audio and video components, and they often contain dedicated areas (either drawers or other spaces) for storage of records, videotapes, CDs and/or DVDs.

Polystyrene (PS) /ˌpɒliˈstaɪriːn/ is a synthetic polymer made from monomers of the aromatic hydrocarbon styrene. Polystyrene can be solid or foamed. General-purpose polystyrene is clear, hard, and brittle. It is an inexpensive resin per unit weight. It is a poor barrier to air and water vapor and has a relatively low melting point. Polystyrene is one of the most widely used plastics, with the scale of its production being several million tonnes per year. Polystyrene is naturally transparent to visible light, but can be colored with colorants. Uses include protective packaging (such as packing peanuts and optical disc jewel cases), containers, lids, bottles, trays, tumblers, disposable cutlery, in the making of models, and as an alternative material for phonograph records.

LaserDisc (LD) is a home video format and the first commercial optical disc storage medium. It was developed by Philips, Pioneer, and the movie studio MCA. The format was initially marketed in the United States in 1978 under the name DiscoVision, a brand used by MCA. As Pioneer took a greater role in its development and promotion, the format was rebranded LaserVision. While the LaserDisc brand originally referred specifically to Pioneer's line of players, the term gradually came to be used generically to refer to the format as a whole, making it a genericized trademark. The discs typically have a diameter of 300 millimeters (11.8 in), similar in size to the 12-inch (305 mm) phonograph record. Unlike most later optical disc formats, LaserDisc is not fully digital; it stores an analog video signal.

Many titles featured CD-quality digital audio, and LaserDisc was the first home video format to support surround sound. Its 425 to 440 horizontal lines of resolution was nearly double that of competing consumer videotape formats, VHS and Betamax, and approaching the resolution later achieved by DVDs. Despite these advantages, the format failed to achieve widespread adoption in North America or Europe, primarily due to the high cost of players and their inability to record.