The compensating system found on most middle- and top-line 4-valve euphoniums helps the player stay in tune when using combinations of valves. In this video I play a simple concert Bb major scale (a C scale in treble clef euphonium) through a full octave in the low range (which is when the compensating system comes into play). The diagram shows the compensating system in action. The lower loops shown are the extra slides found on the rear side of the 3 main valves.
Notice around 0:07 how we go from using the open horn with an easy air path on Bb, and then to go up to C we bring in almost all possible tubing. That is why a player must practice such transitions to become good at keeping the sound smooth!
See the page below for a full explanation (and you can get to the interactive diagram via a link near the top of the page):
[ Ссылка ]
