Complex sentence: The vibraphone resembles the xylophone, marimba, and glockenspiel, one of the main differences between it and these instruments being that each bar is paired with a resonator tube that has a motor-driven butterfly valve at its upper end.
Split into simpler sentences: The vibraphone resembles the xylophone, marimba, and glockenspiel. Each bar is paired with a resonator tube that has a motor-driven butterfly valve at its upper end.