Alrighty, so, despite my mental short-comings, I got Sam and Max working on Scummvm. Unforunately, it didn't help. The voices still cut out as soon as you enter the carnival tent to talk to the owners. Also, I found the voices up until that point sounded a little crackley, which I didn't notice when playing the game without Scummvm. So far as I know, the glitch only affects 2 points in the game, the carnival, and Conroy Bumpus's song at Bumpusville. The easy way around it is to just enable subtitles at the carnival, do everything you need to do there, leave, save, quit the game and open it up again from the save point. Voices will be back and will be fine for the rest of the game, except for the song, but oddly enough, it's only the song, the voices work fine before and after, it's just the song itself which gets muted. The front entrance of the carnival doesn't seem effected by the sound glitch, only the main tent, Trixie's trailer/cone of death, and sometimes the TOL, but it appears intermittent there.
Anyway, it's not really a huge problem in the grand scheme, I'm just happy to have Sam and Max at all, but it'd be nice if it worked properly. I've tried it on my Win2000 computer, and my friends XP and on both the voices cut out in the same spot.
Nothing can kill the Grimace.