Just wondering if other folk have a back D that will screech under higher pressure unless backed off a bit?
mine does, but it seems fairly livable, if I don’t lay into it..
I guess “higher” is pretty relative…
R
I hope you can get rid of the screeching, I have had that in two reeds and it was really annoying. The second reed also screeched on the second octave a and b. Both reeds were otherwise very good and had a great sound and were loud. I tried to fix the problem in various ways (even oiled the cane parts) but eventually ended up ruining both of them by overscarping and trimming. The other reed was made by a well known pipemaker and the other one was my own.
I’d like to know what causes the screeching to try to avoid building it into future reeds. Any ideas?..
Samppa
More commonly the problem I’ve had is a sinking/two-tone back D requiring less pressure to keep it in tune.
You might have a leak close to the binding. Try a little nail varnish on the sides of the reed.
yeah good thinkin PJ..
Just turned the heat on in your house too, dintcha?? 
cant fool me 
I associate this also with reeds that are too stiff. Since stiffness of reed blades may be increased by dry conditions, it makes sense that it may come on in winter - especially if your reed setup is such that it also opens under dry conditions (this depends on details of reed construction). An overly hard-blowing reed often has this problem also.
Is the back d rather sharp when this happens to you?
when I back of the pressure, it sounds great.
When the weather changes, I drag out the old humidifier and get it steaming so that I can have better than 45% humidity.
The first thing I check for on any reed problem is leaks. Leaks in the binding can drive you nuts, so scrub the binding with wax and polish with a cane scrap. A white wood glue (Elmer’s) is good for sealing the sides of the reed.
Assuming no reed / reed seat / chanter leaks, then you may have an unbalanced scrape.
How does the reed crow? Is there a whistle sound before the reed completely closes? If so, then the lips aren’t closing all the way across at the same time. If the center line is too thin, then when the reed attempts to close, there is a leak on one or both sides of the reed. If the center line is too thick, there will be a leak in the middle of the lips.
You will need to examine the reed closely while pressing just above the bridle and using magnification.
Hopefully, there will be enough meat in the reed to scrape out the lip leaks.
@ straycat- the 2-tone back D has long been my #1 problem. Perhaps a seperate thread for that is in order?
Hmm, do you perhaps mean a “breaking” back d? (as opposed to a sinking back d)…
boy, what did we do B.P.F.? (before piping forums)
maybe I should whip together a recording of the screech tonight..
so all can hear the thing.
thanks all for the great reed knowledge transfer!
Is that a very common problem? I’ve been ‘playing around’ it. Like, easing off the pressure a good bit when coming down from high up in the 2nd octave for example. It takes no less pressure than the rest of the low octave though… 
Cheers
Fairly common, I would say. When making my reeds, I keep the last 2-3 mm of the lips a bit thicker than the rest of the scrape. If the reed is played too closed, the back D tends to sink as well as bottom D wants to gurgle rather than play hard D.
I think that’s a better term, for me at least. A slight increase in pressure causes an abrupt half-tone drop in pitch.
One of the main causes of the screeching back D is the mouth of the staple is too open; this allows too much air when more pressure is applied, and causes the lips to become erratic. Try un-binding the reed, close the mouth of the staple to 1 mm then re-bind. There is a good chance this will fix the problem. As far as leaking on the sides the best, way to seal that is to rub a bit of soft wax into the edges. I use the wax from Gouda cheese. I never glue or lacquer on the sides as this will make a permanent alteration and can actually ruin the reed.
Pat Sky
ok, so a little late in posting this, but here’s the offending ‘screech’ lads.
The oscillating at the end, is me putting a little more pressure on the bag.