Assertion: tuba's valve | /r/CapableOf | lower basic pitch
Facets:
value: by a fourth
type: OTHER
Source sentences:
text: The E♭ bass generally has a fourth valve that lowers the basic pitch by a fourth to BB♭, enabling the instrument (with use of valves) to produce the low E, below which the compass can be continued downward in fundamentals (lowest note producible by a length of tubing), E♭, D, and so on.
text: The valves add tubing to the main tube of the instrument, thus lowering its fundamental pitch.