Posted by ken k on August 28, 2000 at 17:41:38:
In Reply to: Compensating system. posted by Wants to know more on August 28, 2000 at 08:30:32:
As you go lower on the horn it takes more tubing to lower the pitch a half step. That is why the second valve slide is longer on a tuba than on a euph. For example the length of tubing needed to lower a low Bb to an A is less than that which is needed to make low F an E (a fourth below low Bb). Therefore when you play low f with your fourth valve and add the second valve to make the E on a non-compensating euph (or BBb tuba) low E will be sharp. To corect this, manufacturers route the fourth valve tubing back through the first 3 valves and there is actually another set of slides on each valve. This "compensates" the length of the tubing to make it more in tune. ken k