Well, this isnt any big secret, but, As active sonar goes. From what i can tell, the AI uses its active sonar when:
- your within it's sonar's cone, (see pic)
http://www.de220.com/Electronics/Son...20Patterns.jpg
- your presenting a favorable aspect, (IE broadside)
-AND your doing both of the above for X number of seconds or minutes.
If all three criteria arent met, you wont hear much out of the AI. The last criteria combined with very forgiving settings in a couple enviormental variable's is why in stock, you dont hear alot of pinging. In otherwords, It's not like they go around pinging randomly hoping to get a contact.