Yeah indeed, adlib emulation works now flawless (it worked before too, but slowed the game down to uselessness). Works fine with DOTT and Sam & Max and it also seems to be slightly faster than pc speaker emulation at the same output rate. Now I gotta test some of these oversized games like Full Throttle (which used to be unplayable even without sound). And - as promised - ScummVM's loading time is much shorter now. A true win!
One small issue: If I use the override option to adjust audio settings (as gibs described) I get only music without speech and sfx. And apparently there's no way to turn it back on via the game specific config menu. Thus I always have to avoid overriding and only use the global settings. Is it intended to work this way?