activating the beep

[Frederic Baldit]

Hi,
I am a new emacs user (23.2.1)on debian squeeze. When reading the book
"Learning GNU Emacs" (from D. Cameron), I see that emacs should normally
beep in certain circumstances, e.g. when leaving emacs after the current
buffer has been modified and the changes haven't been saved to the
corresponding file and you don't answer "yes" or "no".

In my case, no beep at all is heard, and I cannot figure out why. I have
added in my .emacs file the line: 

(setq ring-bell-function 'beep)

with no success. I also tried browsing the customization, unsuccesfully.
Any help would be much appreciated.
Thank's in advance,
  Frédéric.