Loudspeakers in cars?

Is there any reason (other then being lame) not to use loudspeakers to compete? My friend has ONE 12inch stadium speaker that measured 126db on a 10watt amp, and the speaker is 30watts rms capable. It's range is only about 300hz to 12khz. but if it can handle 3x what we were putting into it, it has got to get really friggan loud!

i guess midranges can put out some numbers:)

doubling the power to a speaker will net a 3dB increase, doubling the power again will net a total gain of 6 dB. I am quite sure a 12" speaker can cover frequencies substantially lower than 300 Hz UNLESS you are talking about a horn that has a 12" mouth to it.

Yeah, it is a horn with a 12 inch mouth.

well, the DRIVER for the horn is only like 1"-2". Everyone knows that coupling a horn like that to a driver will increase it's efficiency quite a bit. That's why they were so popular in car audio 10-15 years ago. Richard Clark used horns to win the IASCA championship 3 years in a row. But be advised, they can be a real booger to install correctly and tune in a car.

Two 6,5" Audiobahn drivers:

http://home.infostations.net/soundwave/video/sixes.wmv