Re: 4 valve vs compensating euph


[ Follow Ups ] [ Post Followup ] [ TubeNet BBS ] [ FAQ ]

Posted by Chuck(G) on January 23, 2001 at 19:19:50:

In Reply to: 4 valve vs compensating euph posted by Mary Ann on January 23, 2001 at 18:20:10:

You're not precisely in tune for all note when you simply pull the 4th slide.

Think of it this way: The first three valves have slides adjusted so that they extend the length of the air column inside your instrument by exactly the right amount to lower the pitch 2, 1 or 3 semitones, respectively. Since the length of each is based on an instrument tuned to an open B-flat. But when you use the 4th valve, you're dropping the pitch of the horn to F and now each of the slide for the first three valves must be longer because now they need to operate as if they belonged to an F tuba.

If you think about it, the amount of lengthening for the valve 1 slide would be about twice that needed for the valve 2 slide and the valve 3 slide would need to be lengthened about 4 times as much as the valve 2 slide. So a single lengthening of the fourth slide doesn't really work as a "one size fits all" solution.

A 4-valve compensator acts by extending each of the first three slides by exactly the amount needed when the 4th valve is depressed.


Follow Ups: