An album is a collection of audio recordings issued as a single item on CD, record, audio tape or another medium. Albums of recorded music were developed in the early 20th century, first as books of individual 78rpm records, then from 1948 as vinyl LP records played at 33 1⁄3 rpm. Vinyl LPs are still issued, though in the 21st-century album sales have mostly focused on compact disc (CD) and MP3 formats. The audio cassette was a format used from the late 1970s through to the 1990s alongside vinyl.
An album may be recorded in a recording studio (fixed or mobile), in a concert venue, at home, in the field, or a mix of places. The time frame for completely recording an album varies between a few hours to several years. This process usually requires several takes with different parts recorded separately, and then brought or “mixed” together. Recordings that are done in one take without overdubbing are termed “live”, even when done in a studio. Studios are built to absorb sound, eliminating reverberation, so as to assist in mixing different takes; other locations, such as concert venues and some “live rooms”, allow for reverberation, which creates a “live” sound. The majority of studio recordings contain an abundance of editing, sound effects, voice adjustments, etc. With modern recording technology, musicians can be recorded in separate rooms or at separate times while listening to the other parts using headphones; with each part recorded as a separate track.
Album covers and liner notes are used, and sometimes additional information is provided, such as analysis of the recording, and lyrics or librettos. Historically, the term “album” was applied to a collection of various items housed in a book format. In musical usage the word was used for collections of short pieces of printed music from the early nineteenth century. Later, collections of related 78rpm records were bundled in book-like albums (one side of a 78 rpm record could hold only about 3.5 minutes of sound). When long-playing records were introduced, a collection of pieces on a single record was called an album; the word was extended to other recording media such as compact disc, MiniDisc, Compact audio cassette, and digital albums as they were introduced