I had a look at the alarmui code again (the one in git). Besides being a bit messy for my taste it looks OK.

The clock-alarm sound file is read from (gconf) /apps/clock/alarm-tone. If nothing is there it will use /usr/share/sounds/ui-clock_alarm_default.aac

[ Just to make sure, the next time you get a silent alarm could you check the output of "gconftool -R /apps/clock". alarm-tone should be pointing to a valid file. And just in case check that the default.aac file exists ]

After that it gives control to libnotify (notify_notification_show), which in turns calls the notification server (via DBUS). Now guess who provides the DBUS notification server? yes, hildon-home

For now I stop but [ also to apologize to @freemangordon for my offensive comments regarding CSSU ] I'll try to have a look at h-h's source code (http://maemo.gitorious.org/fremantle...ees/master/src) and see if I spot anything suspect.