He found the musical rendition by the septuagenarian maestro to be listless.

Listless means lacking energy or enthusiasm; spiritless. The antonym should convey energy, brilliance, or excitement. Scintillating means brilliantly clever, sparkling, or lively, which is the direct opposite of listless. Wearying means causing tiredness; unedifying means not morally uplifting; unengaging means not interesting. Therefore, scintillating is the correct antonym.