Drone Startup -- "Double Tone"

This refers to a dramatic change in sound as a drone is started.
The sound files demonstrate tenor and bass drones separately as
they are mouth-blown in the air. Normally, the reed and pipe will
"double tone" the same way when replaced into the bagpipe.

As air first begins to flow, the tone is buzzy and loud, and
the pitch is unstable. As the air pressure increases, the pipe
increases in loudness and its pitch rises.

Halfway through the sound samples there is a dramatic change. The
tone becomes more mellow, the loudness decreases (even though the
air pressure continues to increase), and the pipe becomes very stable.
Modest variations in air pressure have no effect on the sound.

Drone reeds should be chosen and set-up so that the "double tone"
occurs at a pressure just equal to, or a bit less than, the lowest
pressure which allows the chanter to begin sounding.

The pipes should be blown at a higher pressure than this in order to
get an ideal tone and loudness balance from the chanter. But since the
drones have double-toned, they are now in their stable mode and will
remain steady as the pressure is increased a bit to the ideal chanter
playing pressure.

Bad reeds, improperly set-up reeds, or reeds that are do not match
a particular drone, may not double-tone. In this case they never achieve
sufficient stability, and may be too loud and rough in tone for a good
musical blend with the chanter.

If the reed does not double-tone by the time the chanter is brought up
to pressure, it may simply be too strong for that chanter. Moving the
bridle towards the free end of the reed, which shortens the tongue,
often makes the reed weaker in such cases. Small changes can have big
effects, so this should be tried in small steps of 1/8" or 2-3 mm at a
time. If the bridle is loose it should be retied tightly and the reed
tested before repositioning it. It may be fine as-is.

End of Double Tone text.