Heh. Well, I did about as stark a comparison as you could do. I played through Act 1 and some of Act 2 on the Tower of Power and on the Mega Sg. They just sound… different.
The Mega Sg is of course running through a better sound system than 21 year old TV stereo speakers, so it is crisp and clear with an almost tinny sound. On the other hand, the old everything system has more low end and a full sound that is probably closer to what I remember.
This sort of comparison brings a lot of visual baggage too since the CRT has a look all its own that frankly can’t be duplicated by the Mega Sg IMO. It’s neither good nor bad that way. It’s just different.
Sonic 3 is interesting since it has a prerendered look to the main character sprite which looks better on a CRT IMO as there it covers for the sort of low res appearance you get with prerendered Sonic on a Mega Sg.
But all the visual stuff is not going to change that yes, you can probably make these games sound much better in other ways than what I have upstairs, but it won’t be quite as authentic and you could get a Model 2 modded or mod it yourself to have as good as it could get from OG hardware. That said, I did not seem to have the low fidelity sound that’s in that video. I like to think I have decent ears for this stuff, but that seems excessive.