RealAudio, also spelled Real Audio, is a proprietary audio format developed by RealNetworks and first released in April 1995. It uses a variety of audio codecs, ranging from low-bitrate formats that can be used over dialup modems, to high-fidelity formats for music. It can be used as a streaming audio format, that is played at the same time as it is downloaded.
Satellite radio is defined by the International Telecommunication Union (ITU)'s ITU Radio Regulations (RR) as a broadcasting-satellite service. The satellite's signals are broadcast nationwide, across a much wider geographical area than terrestrial radio stations, and the service is primarily intended for the occupants of motor vehicles. It is available by subscription, mostly commercial free, and offers subscribers more stations and a wider variety of programming options than terrestrial radio.
XM Satellite Radio (XM) was one of the three satellite radio (SDARS) and online radio services in the United States and Canada, operated by Sirius XM Holdings. It provided pay-for-service radio, analogous to subscription cable television. Its service included 73 different music channels, 39 news, sports, talk and entertainment channels, 21 regional traffic and weather channels, and 23 play-by-play sports channels. XM channels were identified by Arbitron with the label "XM".
Radio broadcasting is the broadcasting of audio (sound), sometimes with related metadata, by radio waves to radio receivers belonging to a public audience. In terrestrial radio broadcasting the radio waves are broadcast by a land-based radio station, while in satellite radio the radio waves are broadcast by a satellite in Earth orbit. To receive the content the listener must have a broadcast radio receiver (radio). Stations are often affiliated with a radio network that provides content in a common radio format, either in broadcast syndication or simulcast, or both. The encoding of a radio broadcast depends on whether it uses an analog or digital signal. Analog radio broadcasts use one of two types of radio wave modulation: amplitude modulation for AM radio, or frequency modulation for FM radio. Newer, digital radio stations transmit in several different digital audio standards, such as DAB, HD radio, or DRM.
A boombox is a transistorized portable music player featuring one or two cassette tape players/recorders and AM/FM radio, generally with a carrying handle. Beginning in the mid 1990s, a CD player was often included. Sound is delivered through an amplifier and two or more integrated loudspeakers. A boombox is a device typically capable of receiving radio stations and playing recorded music. Many models are also capable of recording onto cassette tapes from radio and other sources. In the 1990s, some boomboxes were available with MiniDisc recorders and players. Designed for portability, boomboxes can be powered by batteries as well as by line current. The boombox was introduced to the American market during the late 1970s. The desire for louder and heavier bass led to bigger and heavier boxes; by the 1980s, some boomboxes had reached the size of a suitcase. Some larger boomboxes even contained vertically mounted record turntables. Most boomboxes were battery-operated, leading to extremely heavy, bulky boxes.
A subcarrier is a sideband of a radio frequency carrier wave, which is modulated to send additional information. Examples include the provision of colour in a black and white television system or the provision of stereo in a monophonic radio broadcast. There is no physical difference between a carrier and a subcarrier; the "sub" implies that it has been derived from a carrier, which has been amplitude modulated by a steady signal and has a constant frequency relation to it.
Digital radio is the use of digital technology to transmit or receive across the radio spectrum. Digital transmission by radio waves includes digital broadcasting, and especially digital audio radio services.
Sirius Satellite Radio was a satellite radio (SDARS) and online radio service operating in North America, owned by Sirius XM Holdings.
Shoutcast is a service for streaming media over the internet to media players, using its own cross-platform proprietary software. It allows digital audio content, primarily in MP3 or High-Efficiency Advanced Audio Coding format. The most common use of Shoutcast is for creating or listening to Internet audio broadcasts; however, there are also video streams. The software is available to use for free or as a paid cloud service with additional professional features.
Icecast is a streaming media project released as free software maintained by the Xiph.Org Foundation. It also refers specifically to the server program which is part of the project. Icecast was created in December 1998/January 1999 by Jack Moffitt and Barath Raghavan to provide an open-source audio streaming server that anyone could modify, use, and tinker with. Version 2, a ground-up rewrite aimed at multi-format support and scalability, was started in 2001 and released in January 2004.
Broadcast automation incorporates the use of broadcast programming technology to automate broadcasting operations. Used either at a broadcast network, radio station or a television station, it can run a facility in the absence of a human operator. They can also run in a live assist mode when there are on-air personnel present at the master control, television studio or control room.
Altacast is a free and open-source audio encoder that can be used to create Internet streams of varying types. Many independent and commercial broadcasters use Altacast to create Internet radio stations, such as those listed on the Icecast, Loudcaster and Shoutcast station directories.
TimeTrax is a software and hardware platform from Time Trax Technologies Corp. which allows audio recording from satellite radio, Internet streaming and traditional radio broadcasts. The company is best known for its disruptive innovation and leading role it played in the transformation of the business model of the music industry.
AOL Radio powered by Slacker was an online radio service available in the United States only. It had over 200 free internet radio stations.
Almost all radio stations today use some form of broadcast automation. Although some only use small scripts in audio players, a more robust solution is using a full radio automation suite. There are many commercial and free radio automation packages available.
The XM PCR is a satellite receiver sold by XM Radio and discontinued in 2004, amidst piracy concerns. Programs allowed users to record every song played on an XM channel, quickly and cheaply building an MP3 library.
Total Recorder is a digital audio editor software from High Criteria, Inc. which is able to record digital sound either directly through the computer's soundcard, or virtually through its software driver.
Internet radio, also known as Online radio, web radio, net radio, streaming radio, e-radio and IP radio, is a digital audio service transmitted via the Internet. Broadcasting on the Internet is usually referred to as webcasting since it is not transmitted broadly through wireless means. It can either be used as a stand-alone device running through the Internet, or as a software running through a single computer.
