Bang & Olufsen (B&O) is a Danish company that designs and manufactures high end audio products, television sets, and telephones. The company was founded in 1925 by Peter Bang and Svend Olufsen, whose first significant innovation was a radio that worked with alternating current (AC), when most radios then in use were run from accumulator batteries.

Their work with radios and loudspeakers led them to devise a principle: Their products should be capable of honest musical reproduction. They held as an ideal that the music you experienced through their sets and speakers should reach your ears uninfluenced by the limitations of technology. To this end, they rate the psychoacoustics of their products as more important than instrument-based testing of their products during design and testing.

Products from B&O are intended to reflect cutting edge industrial design, in appearance, function and operation. Bang & Olufsen does not employ any designers, preferring that they should be independent of the company.

Many of B&O's products in the 1970s and 80s were designed by Jacob Jensen, whose design firm is still in operation today. In recent decades, David Lewis has been B&O's chief designer, responsible for products that have been much imitated by other manufacturers of home electronics.

The phonograph, or gramophone, was the most common device for playing recorded sound from the 1870s through the 1980s. The limitations that lead to the decline in popularity include the fragility and tendency to wear, the size and means of playback that make it impractical for use in an automobile, and it's imperfect reproduction when compared to a bit-by-bit no loss system. Vinyl records still have a strong cult following.