Nigel Richard gives it a new perspective

As an accompaniment to Nigel’s article on tuning the chanter, here is an article he contributed to the June 1994 issue of Common Stock

A great deal has been written on the subject of chanter reeds . The object of this short article is not so much to add any further detail to what has been said before, but rather to offer a simple graphical perspective m order to clarify the underlying principles. The Information is primarily applicable to Highland and Border/Lowland standard style cane reeds, although I suspect it applies generally to most double reeds for pipes and shawms.
There are basically six things you can do with a reed:
1. Thin the blades with sandpaper or a sharp knife.
2. Cut a small amount of cane from the end of the reed.
3. Close the blades.
4. Open the blades.
5. Change the reed position in the chanter.
6. Recognise the reed is rubbish and bin it.

We are interested in operations 1 to 4. The effect of operating 5 is well documented - moving the reed in or out of the chanter end will sharpen or flatten all the notes, the closer the note is to the top the more relatively It will be affected. Before making the final adjustment, the reed should be basically in tune and playing at the correct pressure. When adjusting the reed we are likely to have four ways we want to change it:
● Make the reed harder to blow (giving a louder more robust sound).
● Make the reed easier to blow (giving a softer sound).
● Make the reed sharper overall.
● Make the reed flatter overall.

Tying the four actions with four effects we get the graph below

The attractiveness to me of this particular way of looking at reed adjustment is that it illustrates the dual effect that any action you take will have. It is, for example, no use continually cutting more off the end of the blade in order to get the reed sharper, if you do not appreciate that it will also make it harder to blow. Again, if the pitch of the reed is right but it is too hard to blow, combining actions 'A' and "B'' should make it easier to blow without affecting the pitch. At this point i should mention that there is some variation in the effect depending on the exact part of the reed that you sand or scrape. in the above graph the action considered is slight thinning of the whole blade; generally, thinning the tip will tend to flatten the top hand and make it easier to play, thinning the middle and shoulders will tend to make the sound less tight and the bottom hand notes more responsive.