A dual cassette deck, sometimes called a double cassette deck, is an audio player and recorder with two compartments, or wells, for cassette tapes. As the first cassette plays, the audio can be copied onto the second cassette. The recording can proceed at the normal speed for listening to the audio, or a dual cassette deck may hasten the recording with a common feature called high speed dubbing.
The recording well of a dual cassette deck also can be used to record from other audio sources. These might include a turntable, CD player, radio or microphone in an audio component system. A dual cassette deck cannot, however, typically record from multiple audio sources simultaneously.
Other features common among dual cassette decks are auto-reverse and relay play. Through these features, a listener can hear all four sides of two cassettes without manually stopping and restarting the player or turning the cassettes over. When the player reaches the end of one side of a cassette, the flip side starts automatically. This action is called auto-reverse. When the second side of one tape finishes, the tape in the other well can be triggered to play via the relay play feature.
Some cassette decks also offer the ability to convert audio from a standard, or analog, cassette into a compact disc (CD) format or a digital audio format, such as an MP3 file. This is helpful for people who have music collections that predate CDs and MP3s and who want to listen to those collections on digital players. A dual cassette deck is typically about 17 inches (about 43 cm) wide, 13 inches (about 33 cm) deep and five inches (about 13 cm) high. It requires a flat surface to be placed on, an electrical outlet to be plugged into and it usually requires separate speakers to listen to the audio.
Sales of the dual cassette deck peaked in the 1980s and 1990s, but the roots of its ultimate popularity were established in the 1960s, with the development of compact cassettes. By the mid-1970s, however, the public had embraced compact cassettes as an alternative to the existing, larger, more complicated reel-to-reel setups for audio recording. Sony's introduction by 1980 of a palm-sized personal player called the Walkman® further fueled cassettes' popularity. Buyers now had an easy way to listen to music anywhere through headphones.
Through much of the 1980s and 1990s, compact cassettes were also a preferred format for other mobile audio players, particularly players in cars. The cassettes were smaller and easier to store than the previously popular eight-track tapes. Compact cassettes also had an advantage over the vinyl records played on turntables in homes: They could be played on the road without skipping or becoming damaged at every bump.
As compact cassettes grew more prevalent and improved in sound quality, music lovers gravitated toward dual cassette decks as a means of customizing play lists on mix tapes. For example, a jogger might choose a variety of high-energy songs from different cassette albums for his Walkman®. A suitor might choose an array of love songs to give to a love interest. By tapping the public's desire to customize a listening experience, the dual cassette deck laid the foundation for many of the subsequent trends in music gadgetry.