soundboard
A wide, flat board placed within, or forming part of the body of, a musical instrument in order to improve vibrations and increase volume.
Other meanings
A mixing console used to combine and blend different audio sources to a single output.
A sounding board.
Where this comes from
This definition is adapted from “soundboard” on Wiktionary, by its contributors, published under CC BY-SA 4.0. This page is published under the same licence.