Assertion: bassoon's instrument | /r/Synonym | the u-tube
Facets:
Source sentences:
text: The bassoon at that time typically had 8 keys, but Almenräder increased the number of keys, making repeated innovations such as improving the part of the instrument where its tube bends back on itself, known as the "U-tube", making the pitch easier to control, and increasing the instrument's volume.
text: He increased the number of keys and made other innovations such as improving the part of the instrument where the tube bends back on itself, known as the “U-tube.