It comes to mind that early games didn't often have sound(s) playing during attract mode, and it was a precarious thing, though in a way it made sense because it told you the game was ready to play. Indeed in the early days, if there was too much going on we would watch often as we'd play, at least until the attract was familiar. Definitely by the late 80s this had changed, because it was more attracting I guess to the younger generation who were used to more noise in general, and by the 90s I'm betting that no sound meant (at least to the kiddies) that something was wrong with the game, which was probably often so in such case.