Music Shop, Digital Media, Ambient sound
Music Shop
A record shop is an outlet that sells recorded music. Although vinyl records and audio cassettes are no longer sold in the majority of music stores, in favour of compact discs, people still use the term "record shop", in conjunction with "CD shop" or "music shop".
Originally record shops were private run and independent businesses, meaning that prices could differ greatly from town to town, store to store. Today music shops are largely chain owned and thus prices are fairly similar regardless of the wealth of the town. In the United Kingdom the national chain style of selling records and tapes took off with Our Price, itself originally a small independent business founded in the early 1970s that expanded nationwide.
Competition (like any major business) is fierce, proven by the closure of Our Price in 2004 after several rival chains emerged in the 1980s and 1990s, including HMV, Virgin Megastore and MVC. Around the world, the traditional record stores (chain or independent) are currently suffering from mail order (most notably on the Internet), as well as supermarkets selling recorded music, and digital downloads.

Digital Media
Digital media (as opposed to analog media) are usually electronic media that work on digital codes. Today, computing is primarily based on the binary numeral system. In this case digital refers to the discrete states of "0" and "1" for representing arbitrary data. Computers are machines that (usually) interpret binary digital data as information and thus represent the predominating class of digital information processing machines. Digital media ("Formats for presenting information" according to Wiktionary:media) like digital audio, digital video and other digital "content" can be created, referred to and distributed via digital information processing machines. Digital media represents a profound change from previous (analog) media.
Digital data is per se independent of its interpretation (hence representation). An arbitrary sequence of digital code like "0100 0001" might be interpreted as the decimal number 65, the hexadecimal number 41 or the glyph "A". See also: ASCII, Code.
Florida's digital media industry association, Digital Media Alliance Florida, defines digital media as "the creative convergence of digital arts, science, technology and business for human expression, communication, social interaction and education".
There is a rich history of non-binary digital media and computers.
Ambient Sound
In atmospheric sound transmission or noise pollution, ambient noise level is the sound pressure level at a given location, normally specified as a reference level to study a new intrusive sound source.
Integrating Sound Level Meter
Ambient sound levels are often measured in order to map sound conditions over a spatial regime to understand their variation with locale. In this case the product of the investigation is a sound level contour map. Alternatively ambient noise levels may be measured to provide a reference point for analyzing an intrusive sound to a given environment. For example, sometimes aircraft noise is studied by measuring ambient sound without presence of any overflights, and then studying the noise addition by measurement or computer simulation of overflight events. Or roadway noise is measured as ambient sound, prior to introducing a hypothetical noise barrier intended to reduce that ambient noise level.
Ambient noise level is measured with a sound level meter. It is usually measured in dB above a reference pressure level of 0.00002 Pa, i.e., 20 μPa (micropascals) in SI units. A pascal is a newton per square meter. The centimeter-gram-second system of units, the reference level for measuring ambient noise level is 0.0002 dyn/cm2. Most frequently ambient noise levels are measured using a frequency weighting filter, the most common being the A-weighting scale, such that resulting measurements are denoted dBA, or decibels on the A-weighting scale.
Ambient noise level is sometimes called background noise level, reference sound level or room noise level.