Rayray8, 01-08-11: 135db in a car is pretty easy to do with subwoofers. i use to compete with my car about 9 years ago and only had 1 12" subwoofer and would score 136db any day. these competitions are bass only, and usually people use simple test tones to hit one frequency. there are vehicles now that score well over 170db in these competitions.If we optimistically assume 110 db for 1 watt, 170 db would require 1,000,000 watts. Doesn't sound too likely to me. Fortunately :-)
Elevick, 01-08-11: Imagine what it takes to get to 170db if you keep doubling your power to gain a measly 3db? You need to gain about 10db to double the perceived volume. Even with 102db speakers (which are rare), it takes more wattage than any amp I've seen to get 170db. I imagine that it sounds pretty crummy and distorted at those levels.
Regards,
-- Al