Composite regulator reed?

[Murk]

Interesting Geoff! I have a Mathematics background so this intrigues me. When you say "focus point", are there conic sections at work between the reed and bore? Of course, there's a high probability I'm entirely reading too much into the words "focus point".

[an seanduine]

Two points:
Murk, if you have the math background you might enjoy perusing Cornelis Nederveen's Acoustical Aspects of Woodwind Instruments. Nederveen has a section on reeds, single and double.
Geoff, my limited short term experience with a cedar chanter reed bears out what you say of a rise in tuning. Although, even after an hour or more, I have not seen a full 20 cents rise. Max I have seen is about 11 cents. . . .so far

Bob

[uillmann]

All chanters rise in pitch during playing, 10 to 20 cents, even without the effects that may occur by quick changes of temperature, bringing a set into a session.

Sometimes, such as while playing in dewy air, perfectly strong reeds will become quite soft and pliable, to the point where they are inaudible against the meekest fiddler, and must be constantly pinched closed in order to remain sharp enough. ☞ On such occasions, the reed should be opened up again before putting the chanter to bed. Other times, say when going out to play in the full sun, a reed might be stripped of moisture so fast that it may flatline, even terminally.

It seems to me there may be too much going on with any given reed in any given environment to make sweeping generalizations about reed behavior. Unless one is playing in a completely static environment, they have their own behavior, sometimes erratic, sometimes predictable. Treat them with the utmost care.

[Mr.Gumby]

while playing in dewy air, perfectly strong reeds will become quite soft and pliable, to the point where they are inaudible against the meekest fiddler

Hmmm. Are you sure? Dewy=humid I assume and humid opens reed, reed gets loud(er) and stiff, in my experience (and flattens around the A and further up and down the scale, depending on how far it opens up). But we play in very different climates.

In general I feel my (chanter) reeds want to sit in one exact spot, moving them up or down will generally upset things too much.

[rorybbellows]

Having a selection of different thickness rushes(guitar strings)in your pipe box, is a way around temporary raises in pitch without having to move the reed.

RORY

[uillmann]

Dewy=humid I assume and humid opens reed, reed gets loud(er) and stiff, in my experience (and flattens around the A and further up and down the scale, depending on how far it opens up).

Yes, humidity opens the reed, and like you said, it gets flatter, not 10 - 20 cents sharper as mentioned above. The reed may be more open, but the cane becomes softer, and therefore is able to stay in concert pitch at a much lower elevation. I find the cane gets stiffer in the bone-dry air of winter, and the elevation shrinks down a little and therefore tends to play sharper, and must be opened slightly with the bridle. I only resort to moving the staple in or out of the reed seat twice per year, only if needed, because of the intonation issues raised above. Regular adjustments are accomplished solely with the bridle. Naturally, there's more than one way to skin a cat, but stiffness and elevation, although related, are two separate variables.

[PJ]

I always thought that higher humidity caused the cane to swell, reducing internal volume, making the reed sharper and quieter.

[rorybbellows]

Different kinds of humidity probably cause different results

RORY

[uillmann]

I always thought that higher humidity caused the cane to swell, reducing internal volume, making the reed sharper and quieter.

I suspect you are accustomed to reeds of a different ilk. A reed without much natural camber left will soften and collapse, as opposed to expanding and opening. Although reeds of that nature may not offer me as much tonal pizazz as I like, we are all striving for different timbres, and no one approach will suit all players' preferences.

[Driftwood]

Don't forget to take temperature into account. Warmer equals a rise in pitch.