Bouncing Down (also called, "reduction mixing", "bouncing tracks", or simply "bouncing") is a multitrack audio recording technique which takes advantage of magnetic tape’s rewritable nature in order to circumvent its limited number of tracks. Even as analog tape recorders have grown in sophistication and track count, the technique remains an important tool in analog music production.
Process
The technique involves combining multiple previously recorded audio signals. A series of discrete recordings can be printed (bounced down) from their individual tracks on the tape's surface to either an unused monophonic track, or panned across an unsused stereo pair of tracks, thus freeing up additional space for further overdubs. The process can be repeated indefinitely, resulting in increasingly layered recordings. However, additional machine noise, tape hiss, and tape saturation will be added to the recording with each consecutive bounce.
For example, if there are eight available tracks, a kick drum, snare drum, hi-hat, rack tom, floor tom, and cymbals can be recorded to six individual tracks. These discrete recordings can then be individually processed, mixed together, then bounced down to the remaining stereo pair. One is now left with all the drum recordings in a stereo field on two tracks with six tracks newly available to record additional instrumentation.
Examples
Studer J37 4-track tape recorder (1964-1972), Abbey Road StudiosDespite the availability of 8-track recorders, The Beatles' 1967 album, Sgt. Pepper’s Lonely Hearts Club Band, was recorded using only a 4-track machine and took over 400 hours to complete. To realize the album's complex orchestration, producer George Martin would bounce down successive recordings, slowly layering overdubs to achieve the Beatles' desired sound.
For much of the production of their 1966 album, Pet Sounds, Beach Boys co-founder Brian Wilson recorded the instrumental portion of the album using a 4-track recorder. He then bounced these recordings onto a single track of an 8-track tape, using the remaining seven tracks for vocal overdubs.
Use in Digital Music Production
In the context of digital recording technologies, which since their introduction in the late 1960s have developed to allow for a near infinite number of individual tracks, bouncing becomes an esthetic or organizational decision rather than a necessity and the term often refers to creating a mono or stereo audio file from the digital multitrack in the Digital audio workstation.
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