How do I measure how loud a car audio system is?

How to replace my factory car speaker?

• I am driving a 1993 Toyota Corona with a Pioneer head unit (45Wx4),which was imported from Japan to Oz. As it doesnt have rear speakers, I wanna upgrade my sound system by adding 4 3-way speakers, 2 in the front and 2 in the rear. However, my car has an air purifier in the back system which reduce the space for the rear speakers and I couldnt install a 6x9 pair. I dont know how to measure the front speakers either. So if anyone knows about my car and how to get the right speakers size or any ideas how to upgrade my systems, please advise me . My budget is about 250 Oz bucks so I think i gotta install by my self. And do you know if 4 3-ways or a splits with 2 tweeters and 2 2-ways speakers is better? do I really need an amplifier to get the sound work? I'm not that into heart-break bass but still want some to increase the experience. THanks

• Answer:

  Try using speaker size spacers.That should raise the 6x9's up so they will fit.If you don't know how to take out the front speakers,find a Haynes manual ,follow the steps and do it. I have always liked 3-way speakers.Many years ago I had a 1968 Dart with 10 spkrs and NO distortion.I installed everything myself and oh what a sound. I had 2 6x9' in each door,2 6 in round under the dash,2- 5 in inside the dash.2 big magnet 6x9s under the back shelf and 2- 6 in round also on the back shelf. Have fun and enjoy the sounds!!!