Deciphering (Some) DDO Sound Cues

Have you ever noticed, while you're running a quest, a 'roaring', 'breaking', or 'ka-thunk'-ing sound?  I hear them all the time.  I've asked my running buddies, but either they didn't know or they didn't hear them (or they just didn't want to tell me - I suppose that's always a possibility - hehehe).  Well, I finally figured it out the other day.
I was running some Gianthold quests and, sure enough, I kept hearing the sounds.  Not constantly, but a couple of times throughout the quest.  And only in quests, not wilderness areas.  It finally dawned on me what they were.  So, the next quest, I kept my "XP" window open to verify.  Sure enough, that's what they are.

"What?", I hear you ask.

The "ka-thunk" always happens after disabling a trap control box; the "breaking" after, well, breaking a breakable; and the "roaring" after killing a mob.

Yep - they let you know when you have obtained the various XP bonus tiers of "tamper/ neutralization/ ingenious debilitation", "mischief/ vandal/ ransack", and "aggression/ onslaught/ conquest".  There might be an audible clue for "observance/ perception/ vigilant sight" bonuses, but I have no idea what it would be.

I'm just glad I finally figured out what the other sounds were.  I knew they meant something, just not what.  I have a similar 'problem' in STO - that game is full of sounds - always twittering, tweeting, whistling, buzzing, and what not.  Some I know, but most...I have no clue as to what they mean.  But they must mean something.

Mustn't they?