A Highland bagpipe chanter reed is what is known as a “double reed.” All double reeds (such as in bassoons, oboes, bagpipes, bombardes) work based on a common principle: the oscillation of an air column maintained by the flow of air over and through the reed. A double reed is a reed with two identical blades of cane (Arundo donax) vibrating against each other as air passes over it.
A Highland bagpipe chanter reed is constructed from two triangular shaped pieces of cane (the blades). The cane is profiled and gouged to create a slight inside curve before the pieces are placed together over a copper or brass tube with a crimp in one end (the staple). The cane is then tightly wrapped in cord and secured in place (the binding).
The vibration and resonance of a chanter reed stems from the initial vibration of the blades that occurs when air is passed over it, and the acoustic dampening that occurs as the vibrations pass through the narrower part of the reed at the staple. The vibrations are then projected through the conical bore of the chanter and through the finger holes. Size and thickness of the blades, and curvature of the opening between the blades (the aperture), will determine the necessary speed and pressure of air at which the reed blades vibrate fully.
Differences in reed resonance begin with the structure of the blades and the size and shape of the aperture between the blades. These features will determine the performance and stability potential of the reed as well as the overall airflow/pressure needed to make it vibrate, i.e., how long it might last and whether it is “easy” or “hard.” The reed’s sound character will be determined by the bore of both the chanter stock and the chanter itself. All of these things assume that a constant, steady airflow is maintained. Fluctuations in airflow through the reed fluctuate its vibration and thus its acoustics, much like embouchure changes an oboist would apply to their instrument. A concert woodwind player introduces dynamics and color with adjustments to airflow. Highland bagpipers cannot adjust volume, and changes in airflow will have a negative effect on a piper’s sound. Bagpipers must maintain a fully pressurized airflow to get a steady sound from the reeds. Full dynamics are then created by the fingering on the chanter. A constant, full vibration of the chanter reed is essential.