You're absolutely right, Eddie. Generally I need to add some reverb when the room is full of people, to make the overall sound more "live".

I normally play with the equalizer, with reverb and delay to reach the best possible sound. Am I forgeting any other important parameter?

I found an interesting set of technical essays that gives some theoretical background. Here's the link to one of them, "Acoustics for music"; in the bottom, there's
a yellow little animal :-) that links to the whole set of essays.
http://arts.ucsc.edu/ems/music/tech_background/TE-02/teces_02.html

Thanks, José.