This is for my truck, but I believe it's still on topic, as an audio system is pretty similar in any vehicle, for the most part. The truck is a '96 Chevy 1500, x-cab.

When I got it the stereo was the base GM, AM/FM stereo cassette player, with stock paper/whizer speakers all around. It sounded like total chit. The "system" now consists of:
*GM AM/FM Cassette player/CD changer headunit (most powerful one they make I believe)
*Eclipse, two way, 4x6 rear speakers
*Infinity 605 CS(6-1/2" woofers, 1" separate tweeter and crossover), mounted in the doors on the stock location. The stock location is front lower door for the woof, and just above knee hight toward the front of the door for the tweeter. The tweeter is at about a 30* angle from vertical toward the center of the vehicle. If you've ever been in a loaded 95-99 chevy truck or suburban and seen the stock tweeter loaction, that's where my tweeters are located.
*MTX T-form sub, under rear seat, wired in parallel to the FR speaker, off the head unit. Yeah, yeah, give it to me!

Now, the installation of the new headunit easily overwhelmed the stock speakers. So I installed the above, all powered off the "high end" factory head. These mods made a huge difference. HUGE. But there is still a long way to go. Here are the problems with the system:
*The Eclipse's in the rear can't handle the power/bass. At medium volume levels and a high bass setting, the woofer hits the end of it's travel, I believe, as it make a "pok-pok-pok"ing noise with each bass hit. Fading it to the front helps that but hurts the second problem;
*Lack of stereo separation and imaging. I mean it's there, but it isn't life like, and it never astounds me, as a good system will continually do.
*Lack of clarity (?). Here again, it's clear, and the Infinity tweeters seem good and strong, but it's not a great sound. The other day I put in a CD -a band called Acoustic Junction. There is a flute section in one song. Sounds kind of like the flute of Jethro Tull, in the way the player sort of "spits" over the flute to start each note, makeing a very sharp, edgy sound. That sound is entirely missing from my truck's stereo. As is the actual "wind" sound you can hear on a good system as a flutist blows over the instument.

In my Trans Am, all these elements exist. Spacious stereo sound that transcends the vehicles actual size, super clear detail of even the most subtle sounds -and that's in a car with far more road/exhaust noise- and great, 3-D sounding bass. Granted, I don't expect big bass from a T-form powered by a head unit, but the rear 4x6's hitting the end of their travel isn't helping at all.
Soooo, my questions;
1. Would creating a custom enclosure for the door woofs and the 4x6's improve the bass sound/richness, and in the case of the 4x6's, would a sealed enclosure stop the over-travel of it's woofer?
2. How can I improve the stereo imaging/clarity? Is it a power issue? It doesn't seem so, the head always seems able to take more twist of the volume w/o distortion. Should I move the tweeters up out of the doors, to on top of the dash?

Please don't tell me "it's junk" or "that's stupid". Give me objective information as to where the changes NEED to take place to get the sound QUALITY I'm looking for. Rember, i'm not building a "boom system" here, I'm looking to "tune" what I have. Thank you in advance.

 

How do your speakers sound w/o the sub running off of one channel? It seems like that would be messing with your h/u and it could make a difference as to how your other speakers sound.

 

I don't know why I didn't think to disconnect teh sub and listen to that. What a moron I can be sometimes! I DID consider what effect hooking it up might be, but never disconnected it once the whole thing was installed to "check". I'll do it tonight, and report back tomorrow. Thanks for the brain adjustment!

 

I disconnected the woofer and noticed a very marginal imporvement in the sound quality, and a very noticable loss in bass. The very minor improvement in the front doesn't even come close to getting me where I want to be.

I listened to the same song yesterday, in my friends '03 Dodge Ram 1500 Hemi, quad cab, and that BLOWS my system away, in the clarity and imaging I'm talking about. He has the stock and factory, Infinity sound system. I don't know where the short fall is in my system.

Should I move the tweeters up on the dash?

Will Amping the front speakers improve the clarity and imaging?? I have a Soundstream SX 300 amp sitting around right now.

Would a custom, sealed enclosure improve the bass problem in my rear 4x6's??

I think a good way to describe my system now is like this. It is loud, and it seems fairly powerful but the sound sounds manufactured -mechanical. It sounds as if the system is working hard though is seems to be willing to work hard. By comparison, the sound in my TA, and my friends Ram, sounds musical, effortless, natural, and realistic. That's what I want.