A vocal processor was the speech-regulating subroutine of a hologram's matrix. After the USS Voyager's holographic Doctor introduced her world to music in 2376, Qomarian composer Tincoo wrote a composition that was far beyond the ability of The Doctor's vocal processor to handle. (VOY: "Virtuoso") When The Doctor continually berated Harry Kim for his piloting skills on an away mission in 2377, Seven of Nine jokingly suggested disconnecting his vocal processor for the remainder of the trip. (VOY: "Body and Soul")