Can minor illusion be a cheap substitute for the Actor feat?

[Hiro Quester]

Imagine you have cast disguise self, and are impersonating the King of Town, who you have heard speak often.

The Actor feat enables you to impersonate them more successfully by being able to mimic the speech of another person or the sounds made by other creatures, and have advantage on skill checks to pull this off (and +1 CHA)

But minor illusion can create sounds, including "someone else's voice".

So can I cast disguise self, and then just use minor illusion to make my voice sound exactly like theirs? At least a brief "Guards! Arrest these criminals and lock them in my deepest dungeon!" seems like it should be possible.

Neither spell requires concentration. Its easier to detect, probably, since it's opposed by your spell DC rather than your Deception skill (with advantage).

But if you have other more desirable feats in the works, it seems that minor illusion is a cheap (if more risky) substitute.

[Amnestic]

You can, but Minor Illusion has somatic components, which are gestures that are clearly identifiable to onlookers as spellcasting.

People might get a bit confused as to why the King is constantly making spellcasting gestures before speaking.

[GooeyChewie]

It’s pretty limited. As mentioned above, Minor Illusion can be identified from the S component, which means you need to cast it away from prying eyes. And while the 1 minute duration feels like forever in combat, it would might become problematic if you are trying to impersonate somebody for more than the briefest of encounters. And then of course if you go for a very recognizable face (like the king) you run the risk of the other person actually knowing the king’s current whereabouts.

In short, it probably could work in one-off situations. But it probably won’t work for a long con.

[Hiro Quester]

So the one minute duration can mean that if you can disguise or hide or distract everyone from the S component while you cast the spell, then you can sound like the whoever you are trying to impersonate for the next minute.

That might be doable in certain circumstances.

[Tanarii]

Depends how your DM rules Minor Illusion sound to work. If it's a preset sound or verbalization at the time of casting (pretty normal ruling IMX) and can start with a window of no noise followed by the noise (no something I can recall a DM ruling on IMX), you might be able to get away with it if you can cast the spell out of sight (so the casting isn't observed), followed by a moment of silence long enough to get into view, then appear to say one specific thing. You'd have to time it well to lip sync it tho, and it wouldn't work if anyone said something and expected a response from you.

[Chronos]

You could work around the limitations. For instance, walk around a corner, and then shout back "And go get yourself into proper uniform!" from behind cover. That way, you're not seen casting, and don't need to lipsynch.

But yeah, there are definitely limitations to work around.