Posted by K on October 10, 2003 at 16:46:21:
In Reply to: Re: Re: Re: Re: Drilling out the ol' backbore posted by Brandon Ostrom on October 10, 2003 at 16:18:26:
Brandon, not all of the threads you have initiated make it easy to trust you.
Also not in this case.
Of course the air should move easily through the tuba, when you blow non-buzzed air into it. Anything else would indicate physical obstructions like very deep dents or foreign objects.
However the buzzed air reveals whether the bore progression is more or less optimal.
I have not tried an instrument like yours. Only a Besson Imperial BBb tuba with the same bore and the same narrow leadpipe, but with the 19" bell. this model was made the transition years of circa 1978 to circa 1982, where B&H/Besson had given up their B&H Imperial and Besson New Standard tuba, but still had no Sovereign tubas to offer.
The sample I played was very unreliable in the midrange and upwards. I found it so unplayable, that I rather took my own not very transportable US made BBb's (one at a time of course) to band rehearsals.
The problem with your tuba is the narrow leadpipe. It can be played well on its own terms, lots of great British players have proven that for decades. But if you try to make it sound like one of the bigger US made BBb's, then you will overload your instrument right at its beginning. As you put more buzzed air through the leadpipe, than it can take, then you will create turbulence, which will increase the feel of resistance and make the sound shake.
Ken K has reported on the benefits of putting a leadpipe from a Besson 981 on his older compensating EB with the 15" or so bell.
If you could get your hands on a leadpipe from a current Besson BBb 994 (or the now discontinued 992), then you will get a more open leadpipe with a large receiver (the valve bore is the same, so it will fit your valve cluster. That will give your instrument a more open feel. And the large receiver will open up a much wider spectre of available mouthpieces.
Klaus