Posted by Chuck(G) on November 24, 2001 at 19:02:54:
In Reply to: Re: Re: Re: Re: Re: Re: Re: Marzan/Willson euphonium posted by and to clear that up.... on November 24, 2001 at 14:28:09:
Klaus and I have discussed the issue of Blakely compensation, so I hope he'll forgive me if I answer for him.
Consider a 3-valve Blakely compensator. The third valve is the master and when depressed, adds sufficient tubing to the main airpath and valve 1 and 2 branches to lower the fundamental pitch of the instrument from Bb to G. This allows you to finger F# in tune as 23 and F as 13. However, E as 123 will be sharp, as pressing 13 lowers the pitch of the instrument to F, but the 2nd valve branch has only been compensated to G.
Now, consider a 4 valve Blakely compensating euphonium in Bb, with the master valve being 4. When 4 is depressed, sufficient tubing is added to valve branches 123 to correspond to a fundamental pitch of F. Thus, 14, 24 and 34 are in tune, but any 3 or 4 valve combination involving the 4th valve will necessarily be sharp. That is, intonation when the 4th valve is depressed will only be as good as an uncompensated 3 valve F tuba.
This is why I believe that Klaus is saying that Blakely compensators are not fully compensating. Not that they couldn't be, but the size of the valves needed and the extra plumbing would make for a very heavy (and probably stuffy) instrument.
Do I have this right, Klaus?