Note changes with volume/pressure

[Pipemajor]

Hi all. I was tootling around last night on my Paolo Soprani CBA and I noticed that the vibrato on one note was a bit flat.
As I do my own tuning, when I am playing I usually keep a notebook handy to note down any problems so, after further checks I found that the B flat 5 straight tuned reed altered pitch, going flatter when the volume/pressure was increased, throwing the musette tuning out. :huh:
I have not had this problem before and an internet search didn't show up much.
I do have another Italian PA that I don't use which has the same size reeds as the Paolo so I could just swap the reed over, but if this is a fixeable problem then I would prefer to keep the original reeds.
Any help or advice would be most welcome. Thanks

 

[debra]

The pitch of a note as high as B flat 5 should be fairly stable (low notes do go down noticeably with increasing volume). Besides, the tremolo B flat 5 should behave the same way.
However, the pitch of a note is influenced by the leather valve, a bit by the valve that opens when the reed plays, but also by the valve that closes (and opens when the opposing reed plays).
When the valve for the opposing reed does not close in its "resting" position the reed that plays will play too high. Typically the problem is that the valve has a bit of a "bulge" near its base. As you play louder the valve will be sucked closed and the pitch will go down.
So the solution is not to replace the reed but to check (and maybe replace) the valves, ensuring that they are closed completely when the note is not being played.

 

[Pipemajor]

The pitch of a note as high as B flat 5 should be fairly stable (low notes do go down noticeably with increasing volume). Besides, the tremolo B flat 5 should behave the same way.
However, the pitch of a note is influenced by the leather valve, a bit by the valve that opens when the reed plays, but also by the valve that closes (and opens when the opposing reed plays).
When the valve for the opposing reed does not close in its "resting" position the reed that plays will play too high. Typically the problem is that the valve has a bit of a "bulge" near its base. As you play louder the valve will be sucked closed and the pitch will go down.
So the solution is not to replace the reed but to check (and maybe replace) the valves, ensuring that they are closed completely when the note is not being played.

As usual, you were spot on, Paul.
I took the reed out and the inner valve was wrinkled where I must have used too much glue when I replaced it previously.
I changed the valve again using just a smear of glue and it is now working properly.
A big thank you and back to tootling