Some folks have had success with defining an 'optional action' for a trap or syslog event. One would define the relevant trap or syslog message's optional actional action to launch a *.wav or other audio type file. you can similarly set up the system to email or page you in such an event.
Trick is, the device (or interface) has to _tell_ you it's going down. Lack of resposne to the management host (as is often the case) will not give you the desired audible alert.
