[Trombone-l] Antique horns

[Adrian Drover]

> From: David Leep
> 
> Adrian,  I think you are right about the one-valve-at-a-time, but notice
> that the branch paths at the valves appear to be not extensions but
> shortcuts -- that is why the the tubing goes twice through (once out from
> the mouthpiece, once back toward the bell) for only one set of valve
> crooks.
> (That puzzled me too at first.)  If I'm reading the picture right, the
> valves would represent positions 1 through 6 (and if for any reason more
> than one valve was pressed, only the lowest-numbered one would count) and
> all-valves-disengaged (I hesitate to call it the "open horn") would be
> 7th.


So by pressing a valve the tube length is cut rather than extended.  This
sounds like what is described at length in Cecil Forsyth's Orchestration
book, the six cylinder trombone in Bb.  He goes on to describe the seven
cylinder trombone on which the 7th valve *adds* a 4th making it a Bb/F
trombone which is capable of producing the low B nat.  I don't quite
understand how this works without compensation.

A.