I just installed JVC KDSSX995 HU and Pioneer 120W 2Way Rears in my brother's Falcon EB. At the moment he is using stock fronts.
Comparing to my setup (Read Signature) his system sounds much fuller (more surround feeling) and the thing is all his speakers are connected at this moment to the HU he doesn't have amp or sub yet.
On the other hand my car has good high and low output and I have nice stereo effects but there is no surround feeling.
I'm starting to think that splits are giving different audio stage comparing to coaxs or my speakers are out of phase.

hmm its prob the way the crossovers are set up on the amps. Try changing them. Check the phase also, you can get cd's that test phase.

When you say it doesnt sound full do u mean it doesn't have enough bass from the front or that you can't hear the back speakers?

It has enough hi and low it just missing surround felling

What about mids?

Dont forget that mids contain most of the guitars, vocals and other treble clef instruments in a rock/pop song.

Even the top end of a bass guitar gets around the mid frequencies.

It's your EQing that's out. The best bet is to go completely flat EQ and turn DOWN things that seem too much. Don't boost

EQ's were originally made to cut, not to boost. As a matter of fact, they were made to cut bass! And now everyone uses them for the opposite lol.

It can be due to two things, number one, speaker positioning

number two, staging. Try playing with your gain etc on your amps, that solved my problem quick.

Im sure there are more factors involved, anyone else care to comment? Audio isn't my specialty anymore...

Nice bunch of gear there...

Sounds like you've mainly got a staging problem... Could be a few things.. Rear fill could be pushing/dragging the sound stage through the car (set gains on separate amps, or adjust fader).. Tweeter & woofer positioning in your splits might be way off... The higher the frequency of music, the more directional it seems to the human ear.. In this case, you might have to take your speakers out (hopefully just the tweeter) and have a play around..

Remembered from somewhere on CAA: Cut any bass/treble boosts off, set EQ's to flat (or off), fader and balance to zero... Fade the music all the way to the rear, then shut your eyes and turn the fader up until you can't tell if the music is at the front or rear of the car.. forget about balance, it's probably as close at it's going to get from to centre anyway.

Generally, you shouldn't need to boost any frequencies if everything is going well... EQs should mainly be used to correct problems in frequency response (say, if sound is bouncing off the windows and causing a big peak or dip in frequency response, you can offset this with an EQ). On a side note, I don't know if this is true, but apparently bass boost isn't the increase of a certain frequency band... It lowers every other band except the one specified and raises the overall amplitude of the signal.. This can introduce higher distortion into the signal... Take this with a grain of salt, though...

Hope it helps =)

Everyone here has been forgetting about the Pioneer headunit!

Pioneer headunits (well, the better models) have a nifty feature called SFEQ. Basically, it allows you to control what sound goes to the front and rear independantly. So, you can have treble at the front and bass at the back. This is very accoustically beneficial as the human ear hears bass better from behind and treble better from in front!

SFEQ, or any processor effect, can more of a problem than it's worth at times... Your crossover, coupled with how you set your gains, should be enough to set everything correctly, hence why a lot of people are stating to set bass/treble/eq to flat/off...

Also, if your headunit has an inbuilt crossover, deactivate it... the double passing sometimes causes problems (don't know too much about this to be honest, but I'd just let the amp's crossover do the work) The way I figure, the less processing the signal has to go through, the better, but I could be wrong (*waits for someone to shoot him..*)

hope it helps =)

I fixed the problem by reversing polarity on my rear speakers.
Everything is now sound nice and full.