Assertion: tuba | /r/HasProperty | open-hole instruments
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Source sentences:
text: Bass horns are open-hole instruments made of wood and metal with a folded conical bore, often pitched at an eight-foot C2, with two sets of three fingerholes that serve to close tone holes on the conical air-column, unlike the most commonly known upright serpent, the ophicleide, a closed-hole instrument where the keys serve to open tone holes.