V. A technical term used in
multitrack recording; the practice of recording the same instrumental or vocal track twice and mixing the two sounds together to give them a "thicker" sound. The result is two almost-but-not-identical sounds being heard at the same, resulting in a subtle wavering effect.
One of the first recorded instances of this, and a good place to start to become familiar with the sound, is
Buddy Holly's "
Words Of Love."
cf.
4-track,
Buddy Holly, his producer
Norman Petty, The
Beatles, legendary
Motown producer Phil Spector, and "
Norfolk Sound" guru
Frank Guida