Art's version had a bell, if I recall, which you'd usually hear even before Art read the answer.
Alex's originally did have a sound effect, sort of like what my Mac refers to as \"simple beep\" but with more reverb. And sort of like the tones played in department stores to page managers.
I'm thinking they stopped using it halfway through the first season, back when they let players ring in early, as on the original. Can anyone back me up on this?