Hello,
I made a new reed for my C chanter ant when I play a Bflat (C figuering for a D chanter) I get a note that is higher than the C#.
Is there a rational explanation? How can it be cured?
Sounds as if your crossfingered C is not cross fingering ( not droping down from C# to C nat.) which suggests that your new reed is too stiff. Sometimes chanters with small fingerholes will do this if the reed is not scraped out enough (inflexible)… but it is important to keep the ‘reed head speed’ (that pitch of sound you get when you draw air through the reed by mouth) of a flat chanter to about the A of the chanter ( thus a G in your case)… do not let the reed head pitch drop too far below this note otherwise the upper octave will become hard to obtain, especially above G.
Scrape away at the sides of the ’ reed scrape’ and out into the top corners with something very sharp and fairly small like a scalpel blade so as to make your head more flexible without taking too much more from the centre of the scraped area.
Try moving the reed higher in the socket by adding more hemp.
RORY
Thanks to Bill and Rory. I’ll try that !
Edit: 
Thanks to Geoff (sorry Geoff)