Can anyone think of a reason that the C would be significantly flat relative to the B, and usually actually flatter? I have no rushes in presently, although there is a tuning pin “spike” and have tried cane, plastic and metal, all with similar results. The keys all seal well and the reg itself is airtight. Could this be a staple issue? Thanks.
A few things you could try here. First off, I wouldn’t necessarily be worried if the c is slightly flat relative to the B. You can probably address this by allowing the tuning spike to go up to just below the c hole - either by withdrawing the pin slightly (if it’s longer) or extending /replacing it (depending on the tuning pin arrangement used by your maker). If the c is still slightly flat, try pressing the b key at the same time - this often sharpens it, and means your baritone-g, tenor-c chord will be in tune, arguably more important than having the c in tune on it’s own. You mention the c being flatter than the b altogether, which sounds a bit worrying. I have had this problem before in a tenor reg - in this case the c was sort of crumbling (for want of a better word) under pressure. With a stiff reed or under very light pressure it would play in tune, but scraping the reed to an acceptable level would make it play flat with a sort of strangled tone when blown at the pressure the rest of the notes wanted to play at. I had some luck with this problem using a narrower staple (thanks to Benedict Koehler for that advice). I know some makers use narrower staples for the tenor (Froment uses 3 mm ID for his flat sets, as opposed to 3.2 for the rest, and 3.2mm for his D tenor, as opposed to 3.5 and 4 for the baritone and bass). It later turned out that the bore of this particular tenor had shrunk slightly, a situation later remedied by the maker. I still use a 3mm staple for it, but mostly out of superstition now - I’m pretty sure it plays fine with a 3.2 now as well. The tenor always seems to be the most problematic of the buggers to get in tune in most sets I’ve messed with.
I interpreted the question a little differently - perhaps WBP’s top tenor reg note is actually sounding flat of B, as opposed to C as intended. Of course this is not an uncommon problem, it’s analogous to a sinking back d on a chanter and can be caused by the same sorts of reed woes.
Sometimes a change of staple dimensions will help, but I don’t have a good rule of thumb to try for that, myself - however I do tend to use narrower staples in my regulators than in the chanter as Cormac suggests. Sometimes a particular tenor reg will seem prone to this problem, in which case a stiffer or more open reed may be required (this is otherwise not usually desirable in a reg reed, as Cormac infers). Lastly, a smaller reed head might help.
regards
Bill
Thanks for the suggestions, guys. BillH, you’re correct in that the C is actually usually flatter than the B. Do you (or anyone?) think that rushing the staple would be a worthwhile exercise, or should I just get some smaller tubing to begin with?
Like what Bill said about the narrower head - think that helped with my sinking C too. Try something about 10mm wide or even slightly lower ( if you can get a cane tube that’s narrow enough to do it ). Try rushing the staple by all means - it costs nothing and is reversible. It can be difficult (in my experience at least) to get 3mm tubing - might be easier just to hand-roll it. a .43" wide blank should do the trick