I have been attempting to find an application that will sound a buzzer 
(presumably a synthesized sound through the audio system) when, in a 
laptop, the battery becomes low or the mains power supply is 
disconnected (and the machine has switched to battery power). The gnome 
applet changes from a mains plug visible on the displayed icon to no 
such plug, and then to another icon for a low battery; however, an 
audible warning would be useful.  Note that such a warning should bypass 
the normal sound system settings (e.g., I set mine to mute because of 
audio enabled advertising pop-ups when using a web browser).  I enable 
sound output only when I want to listen to an item.

Does anyone know of an application or application configuration to 
provide this audible power warning?

Yasha  Karant