how can I customize alert sounds

[hellomyzn]

I wanna add sounds(aiff files) into '/System/Library/Sounds' to select my sounds when it notifies me. but it is read-only.
so I wanna change the directory which this system reads
from: /System/Library/Sounds/
to : ~/Library/Audio/Sounds/Alerts/

Please let me know if someone has any clue.

[RococoCoding]

I was also looking into this. I haven't found a way to do it through terminal-notifier, but I was able to have my script run 'afplay honk.aiff' after the notification, which works pretty well!