If you want a top notch car speaker system, then you want a system that performs with front stage and rear fill. That means that the sound appears to be coming from the front of the vehicle.
What you can do to assure proper staging is to use a four channel amplifier that includes some kind of control at the driver’s seat so that you can adjust the volume level of the front speakers versus the rear speakers. You also need to determine the true listening area. That is, where are your ears located as you sit in the driver’s seat.
Once you have determined the listening area, you need to place the speakers in the most advantageous location that provides the right amount of sound to the listening area. For example, installers suggest that you mount the rear speakers a little off axis or in a position that is not directly aimed at the listener. Moreover, you can take a speaker’s ohm rating into account. For example, you can put 4 ohm speakers in the front of the vehicle and 8 ohm speakers in the rear. The 4 ohm speakers will play louder than the rear speakers. You can also put a resistor on the rear speakers to reduce their volume to assure that the front speakers dominate.
Once the front stage, rear fill has been achieved, you will want to widen out the sound. You want the vocals to appear to be coming from the front center with the instruments sounding like they are also in the front but more spread out. Sound processors, equalizers, digital sound processors and other products can be used to spread out the sound. This can also be achieved by the placement of the front midrange speakers in relationship to the front tweeters.
Although the car comes from the factory with speakers in the doors, this may not be the optimum location. Perhaps the best location for the front midrange speakers and tweeters is the kick panel. This is the left and right corners below the dashboard. Custom made enclosures can be constructed that hold a tweeter and midrange speaker and then mounted in these corners. The kick panel could be ideal for a 4-inch, 5-1/4-inch or a 6-1/2-inch midrange speaker and a tweeter.
Or, in your particular car it might be best to put the tweeter in the door above the midrange speaker, in the dash or on the a-pillar. Experts say that it is a good idea for the tweeter to be above the midrange speaker. That helps pull the midrange sound up for better imaging.
Don’t be afraid to experiment. It might be worth taking time and playing with the location of the speakers and then listening to them until you find the optimum location. Then use the processor to fine tune things. The processor can delay the sound of the speakers on the left side from getting to you before the sound from the speakers on the right side.