'm a noob. What's advantages, or disadvantages, of digital volume control
That can be a "complicated question"...
The main issue with regular potentiometers is that left & right don't track exactly. Well... Nothing is "exact" in analog but often it's good enough (better than human hearing). Left and right will always match at zero and maximum but they can be mis-matched in-between.
...I have an old mixer that I built, and there some "play" between the two ganged pots. One pot moves before the other and you have to move it back-and-forth to get left & right balanced! ... I don't remember and I don't use it anymore so I might have actually fixed the play but I remember that left & right still don't track.. (You shouldn't get that bad of a problem in a well-made commercial product but it still can sometimes be imperfect.)
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Digital" volume control can be done two different ways - Sometimes it's just digital
control of an analog circuit, and usually that's preferred.
Usually it's done in the digital domain and some people try to avoid that because when you reduce the level digitally you aren't using all of the "bits" and you're loosing resolution. But that's not as bad as it seems and you won't hear any loss of quality/resolution unless you re-amplify after a LOT of attenuation. It's usually OK for "everyday" volume control because you still get full-resolution when you turn it up to full volume where the resolution is most important.
Plus... You also loose resolution with analog attenuation because by reducing the signal you are reducing the signal-to-noise ratio.(for any noise that's introduced after the volume control). And again, the loss of resolution isn't a problem unless you re-amplify, boosting the noise and signal together, making the noise more noticeable.