Gotcha. Hey thanks guys I really appreciate all the info. I know a lot more now than I did at the beginning. When I'm done with the install I guess we'll see how much more.
Thanks again.
Lewis King
I'm going to try to simplify things a bit, but probably won't Please bear with me...
In a modern car stereo system, where the user is concerned about sound quality, you want 2 or 3 speakers sets for the front stage, a subwoofer(s) and possibly a speaker set for rear fill. The speakers should be 2 tweeters placed above the dash level. 2 midranges placed relatively near the tweeters. 2 midbass speakers typically placed in the stock door locations, called a 3-way, or just tweeters and midbass speakers, called a 2-way.
A DSP allows you to really shape the sound all over your vehicle, front or back. It handles setting the crossover frequencies and slopes for each of your speakers as well as setting time alignment for each speaker. Because of its capabilities, it allows you to ditch the factory (passive) crossovers that come with a set of speakers... this is called an active system.
How this works... each speaker requires one channel of power from an amplifier, so for example, if you had tweeters/mids/midbass speakers you would need 6 channels of power to drive them, 3 channels for left speakers and 3 channels for right. The stereo feeds the music to the DSP which then divides the music up by frequency range to feed the appropriate speaker or speaker set. You setup the DSP crossover frequencies to feed just the highs to the tweeters, just the mid freqs to the midrange speakers and just the low freqs to the door speakers. The DSP also applies equalization to each speaker as well as offering gain adjustment to boost/cut a speakers volume. Finally, the DSP offers time alignment... when you sit in a car, some speakers are physically closer to your ears than others and often the sound from the nearer speakers will reach your ears before the others... time alignment allows you to delay the sound from the nearest speakers so that all the music arrives at your ears at the same time... this is what helps create a more realistic sound stage, as if the musicians are sitting on your dash. Generally speaking, you don't apply time alignment to the furthest speaker and all other speakers are delayed to arrive at the same time as the furthest speaker.
Now we add a subwoofer... we all know it plays the lowest frequencies and it uses an additional DSP channel and a separate amp channel. The DSP again offers the same features to the subwoofer, crossover, equalization, time alignment, etc... Since a subwoofer is in often in the trunk or hatch, it is frequently the furthest speaker away from your ears... not always, but frequently.
Rear fill... there are arguments whether you need rear fill or not. An accurate sound stage is one where the "majority" of the music is coming from in front of you. However, if you have passengers frequently and want a party atmosphere, you might add rear speakers. I run rear fill in my car because I found that with proper equalization and level setting, rear fill actually provides a wider sound stage in my situation. Most would say that rear fill is not necessary.
Anyway, I hope that this explanation is helpful in some fashion and I would make one or two recommendations.
Before spending a bunch of money just to buy something, go to a local get together and listen to a couple of systems. This will help you visualize what kind of system you want... in other words, how serious do you want to get. This hobby is a money pit so if you put some seat time in up front, you can save yourself some cash in the long run.
Once you have an idea of how deep you want to go, pick a budget, ask a bunch of questions about equipment and try to stay within that budget. Good luck!
Closing