How to change Default alert sound in iCal? I would like to change the default sound ("basso") that plays when an Alert is fired from iCal in the notification center?

I have tried changing the sounds in notification center, but it seems to be overridden by the iCal settings. Can the sound be changed to "glass" or any other? 

One way, I can do it is by changing the Alert sound when I create a Calendar Event. This is just too cumbersome to do everytime. 

Please assist.
There is a alternative way to do that.

Go to System/Library/Sounds and create a sound file with the same name as Basso.aiff and it will supersede Basso without the need for deleting a system sound file.