swell box

noun

a chamber containing a set of pipes in a pipe organ or of reeds in a reed organ, and having movable slats or shutters that can be opened or closed to increase or diminish tonal volume.

Origin of swell box

First recorded in 1795–1805

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for swell box

Historical Examples of swell box

The swell-box is made in three thicknesses, each of one inch.
Bell's Cathedrals: The Abbey Church of Tewkesbury
H. J. L. J. Mass
Choir organ, of soft, mellow stops, often enclosed in a swell-box.
How it Works
Archibald Williams
Echo organ, of stops of small scale and very soft tone, enclosed in a "swell-box."
How it Works
Archibald Williams
The organist might leave his Swell-box shut or, by means of a catch on the pedal, hitch it full open.
The Recent Revolution in Organ Building
George Laing Miller