Colecovision > MSX

You can imitate it, though.

Maybe through ultrafast volume changes

*edit: fixed a typo

The fastest ones are the ones in the cart, with noise emulated as tones.
About ultrafast volume changes, the emulator tries to dynamically translate bytes sent originally to SN, into the format of the AY, trying to get the similar sound output.
The way it's built, it's not relying on an interrupt hook. Not sure about conventions, but possible more of a translator than an emulator.

So, ultrafast volume changes are not possible as it is.

In some weeks, I'll play with a good & old pencil and paper drawing some state charts, trying to map some important states from two chips.

that means changing the game sound engine specific logic entirely, and, in general, that would not fit any other Coleco game.
We did it before

@hbarcellos,
normaly music goes all at vertical blank interrupt rate.
is there any indication that coleco games do different.

only thing I can think of is the MSX pac man saying oh shit and game over.
i.e. outside-game effects.
in-game there never is fast changes except the extreme timed demo of dvik.