Posted by Klaus on September 13, 2001 at 05:18:39:
In Reply to: Chris Kratt sousas posted by ken k on September 12, 2001 at 22:28:40:
The tubelengths of Eb and BBb instruments are only to a lesser degree determined by bore and bell diameter.
Hence the pitch mostly can be determined by these rules of thumb:
If the tubing of the main circle, on which the shoulder bearing plate is mounted, is clearly a fake tubing, through which no air is passing, then the instrument always is in Eb.
If the main circle has a double layer of tubing for 3/4, or more, then the instrument generally is in BBb.
The very few doubtful exemptions, are the Eb sousas by King (not all of them) and Weril, that have no fake tubing.
Their valve clusters are very low set in the circle, and their portion of double tubing is closer to 1/2, than to 3/4 of the perimeter of the main circle.
The link given below is a bit clumsy, if you are not familiar with Portuguese (I only can draw on my sparse Latin and French).
Click on "Vitrine" in the left banner. Then go to the US written pull down menu. Go to "Tubas". Then click the Sousa mib.
Klaus