I reckon that’s at least part of it. That said, they won’t take just “any” reed, and in fact individual reeds seem happily transplantable between Coyne pitches. So I think that, while there’s a range of reeds that will work, there doesn’t seem to be a strong trend/variation as one moves from, say, C# to B, as many might expect. In other words, the reed preferences of many of the old chanter types seem to be more tightly grouped than reed preferences of “recent” instruments (i.e. last 100 years, with the exception of O’Mealy who seems to have been a throwback
). This is a subjective impression, but one that I seem to share with a number of other people with hands-on experience of these instruments.
Regarding the MacAloon reed, I believe the chanter in question was heavily rushed when the reed was fitted - which of course complicates things; also no claim has been made that these various reed styles tune the chanters to the same relative pitches; some may produce a much flatter chanter overall than others. Craig Fischer has reported that the best of the “old” reeds described in his SRS article has proven “very hard to reproduce”.
As for dimensions, I personally feel that there’s only so much that dimensions can tell you, where reeds are concerned. For a more familiar case, think of the many reedmaking styles and dimensions that are used, successfully I might add, to reed concert pitch instruments nowadays… hand a chanter to three different accomplished reedmakers, and you’re likely to get reeds of three different dimensions. They may all work “well”; on the other hand, for each of those reedmaking methods, there may be a particular set of dimensions that work, and arbitrarily varying one dimensions or another might produce disastrous consequences. In other words, dimensions are important, and dimensional accuracy may well be critical to success, but the “right” dimensions seem to depend on the maker.
I guess what I am suggesting is that the seemingly dissimilar reeds described as working in “many” Coyne/Kenna chanters may have more in common, behaviorally, than their measurements suggest. It’s a bit puzzling, I agree, since on the one hand evidence suggests that dimensions are all-important where chanter bores are concerned, yet just where one expects the required accuracy to be greatest - the reed staple - experience suggests that we have wiggle room. It may be that, as some have theorized, the reed acts more like a valve and less like a waveguide - in which case the primary variables in the reed are stiffness, mass, and aperture (which helps determine the imaginary point where the “nodal end” of the chanter lies, outside the reed).
Back to specifics - to take another example: one chanter in particular, the Rowsome currently played by Liam O’Flynn; widely (dare I day wildly?) varying dimensions have been reported over the years for “working reeds” for this chanter. They may well have all played satisfactorily, depending on one’s taste; does that mean this chanter is “easy to reed” ? I doubt it. There must be countless reed designs out there that would fail to make the grade.
Possibly things like the pitch of the reed crow would be more reproducible, or possibly the staple (provided the head width is agreed upon).. but I suspect that even these things can be compensated for. Perhaps there is a “family” of reed designs that would fit a particular chanter design, rather than a single set of dimensions, but describing that would seem to be beyond what anyone has attempted to quantify in reedmaking.
Bill