1. A
reed used with certain
woodwind instruments, such as the
bassoon and the
oboe. The double reed is actually two pieces
of reed, formed into
thin blades at the tip and into a
tube
at the
bottom end, which is attached to the instrument.
Instruments that use double reeds have no other
mouthpiece -- the reed acts as the mouthpiece. To play most
modern double reeds, the
tip of the double reed is inserted partway into the mouth, with only the lips
touching it. The lips are drawn firmly around the reed. My
bassoon teacher suggested students use the image of a drawstring
bag when forming their embouchure. Sound is produced when the
blades of the reed vibrate.
2. Also, a term referring to the class of instruments that use
double reeds. The standard double reeds of the modern orchestra
include the oboe, the english horn, the bassoon, and the contrabassoon.
Bagpipes
are also a double reed instrument, having a double reed in each
chanter and drone. With bagpipes, these reeds aren't placed in
the mouth, but are enclosed in a tube, and vibrate as air from the bag is forced through them.
The shawm is a double reed instrument, similar to an oboe but
without keys, that
was used in medieval and renaissance times. It arose in
Arabic regions and made its way to Europe during the Crusdades.
Another traditional double reed is the crumhorm, which is a
curved wooden tube with a cylindrical bore, and a reed which is
covered by a wooden cap with a slit at the top that the player
blows through.
The rackett, or "sausage bassoon" is another Renaissance double
reed which consists of a block of wood or ivory around a foot in
length and several inches thick, which has multiple (often around 9) parallel bores
drilled through it, each connected with another bore at each end.
This has the result that the bore of the instrument snakes through
the block of wood, having an actual length that is nine times
the length of the instrument, so you can get a surprisingly low
note out of a small instrument.