This could be easily accomplished with WebCore issuing the siren’s beep commands. You may find the volume and duration of the beep to be rather annoying. Also everything runs in the cloud so timing may vary from your expectations.
Currently, using my SHM Delay smartapp, I have the GoControl siren set to beep as a warning and reminder when a monitored contact sensor opens creating an entry delay time period. I’ve also set the “length of beep” to 125 milliseconds limiting the duration of the sound, there is no volume adjustment.
For audio confirmation of alarm state changes I’m using an Amazon Hd8 tablet with Lannouncer and Bigtalker that speaks the alarm state change. Visual confirmation includes ActionTiles on the HD8 and status icon lights on a Centralite keypad