Could a bard play an instrument and use a spell (minor illusion, prestidigitation, or major image) to produce the sounds of other instruments, effectively becoming a one-man band for the spell's duration for the purpose of preforming to a crowd?
If the answer is yes but not using these spells, then what spell would be needed? Anything from another casting class?
Best Answer
Yes, a Bard can do this
With minor illusion, a Bard can create an auditory illusion for 1 minute, and that illusion can be complex enough to carry out a conversation. There is nothing stopping you from mimicking any kind of sound.
Of course, since you can copy any sound with a cantrip, it's fair to say the third level spell equivalent, major image, is also capable of doing this. However, note that the visual and auditory components of major image cannot be divorced. You create a visual illusion first, which can produce sounds on its own:
Since the illusion has to be visible, you can't make an invisible instrument playing the lute, so for purely auditory illusions, major image is a bit limited.