Drone reeds.

Please regard this as a "work in progress". I welcome any comments. I am particularly interested if anyone can supply more details on some of the reed types.

The reeds used in the drones of the Northumbrian Smallpipes are single-beating. They have a flexible tongue which vibrates against a relatively rigid body.

The original form was an elder twig or a piece of thin reed cane.

These are favoured by 'traditionalists'. They can have a various tones (good and bad) and once they are playing well can provide years of service. Being made from all natural materials, there is a knack to making them which has to be found and can barely be taught.

By the early twentieth century, some players were using all-metal drone reeds with a thin blade on a relatively thick body.

This technology apparently derives from pipe-organs. Tom Clough certainly used all metal reeds in some circumstances and they persisted until the the 1970s when Colin Ross abandoned them due to problems with verdigris.

Around the middle of the twentieth century, the so-called composite reeds came into use, with a cane tongue on a metal body.

There were two approaches to this which related to the shape of the cane blade. Some makers preferred a blade with a uniform thickness along its length while others chose a wedge shape. This and the all-cane reeds are the most common form at the moment (2006).

Towards the end of the twentieth century the use of plastic tongues gained some acceptance.

The preferred plastic was polystyrene sheet which is widely sold) found favour with some reed makers. This is sold in specified thicknesses (.010", .015", .020", .030" etc) and comes with a relatively smooth surface. It is easily cut, has reliable properties and is fairly independent of humidity.

There has also been some experimentation with veneer-thickness wood and extremely thin plywood.

These are in the realm of rumour, so I will make no comment at the moment.

There is no reason to believe that any of the above forms is inherently superior to the others. Each have their advantages and drawbacks.

I will attempt to list some of the desirable properties in a drone reed:

• It should 'cut in' easily and cleanly as pressure is increased.
• It should stop cleanly as the pressure is decreased.
• It should keep sounding at fairly high pressure.
• The pitch should be fairly independent of pressure in the working region.
• It should be possible to stop the reed by blocking the outlet of the drone.
• It should be possible to restart a stopped reed by stroking the outlet of the drone.
• Should there be any change in the pitch, it should increase with increasing pressure.
• The volume should balance with the other drones (and the chanter).
• The air consumption should be as low as possible.
• The tone should be good.

Perversely, the quality which, in the final analysis is the most important is placed last in the list, but there is no point addressing this final, critical, aesthetic point until the earlier 'mechanical' points are resolved and we have a 'reliable' reed.

In determining the effective pitch of a drone reed, the two major factors are the stiffness of the 'hinge' and the moment of inertia of the blade. The moment of inertia is a combination of the weight of the blade and the distance from the 'hinge' to the centre of gravity. i.e. a combination of weight and length. The moment of inertia increases proportionately with the thickness, while the stiffness increases as the square of the thickness. Thus, doubling the thickness of the blade will increase the moment of inertia by a factor of 2 which would halve the pitch of the reed. On the other hand this would also increase the stiffness by a factor of 4 which would quadruple the pitch of the reed. Combining the two means that, other things being equal, doubling the thickness of a reed blade increases its pitch by a factor of two. Of course, when these reeds are fitted into a drone, the effect is nowhere near as great as this factor of two.

The minimum length of a drone determines the the highest possible pitch which the drone can produce. Any reed which works will produce a pitch lower than this maximum. In my opinion, it is better to produce a reed which is sharper than required and then flatten it either by adding weight to the end of the tongue or by scraping the hinge area to reduce the stiffness of the blade. If this is overdone, the pitch can be raised by adding more wrapping. I do not think that adjusting the wrapping is a good way to make substantial pitch adjustments as this will change the aspect ratio (length/width) of the reed which I am sure will have tone implications which are hard to predict.

I will, at some time, include the dimensions of drone reeds I am using at the moment.

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