system installed, but not satisfied

Ok, I have a 1999 Dodge Durango with the Premium Infinity sound system.    One of my stock front door speakers blew,  so I took this opportunity to replace all the speakers and the amplifier.    I left the stock head unit, but replaced every thing else.     In the front doors I installed  Alpine SPR-17LS  6.5in Component system speakers.    In the rear doors I installed  Alpine SPS-170a  6.5 2-way speakers.     I'm pushing all these with an Alpine MRP-F240  4 channel amplifier,  running from the Dodge stock head unit.

The system just sounds kind of dull.   I really expected much more from it.   Its almost as if the stock system sounded better.    

I did install a cheap line level converter to convert the speaker level to RCA going from the head unit to the amplifier.    Could this be my problem?   Should I just run to the speaker level inputs on the amplifier from the head unit?    Do you think it would sound much better than my cheap line level converter?

If anyone has any insight or tips,  it would be greatly appreciated.

Thanks,

Matt

Thanks Brison,  I did totally bypass the factory amp.    Everything on the Alpine amp is set correctly, gain, crossover, Bass EQ.     The sound is ok, it has highs and lows,  it just doesn't sound like I think it should.    Not as loud as the factory system.     Almost sounds like it is playing down in a well.

Thanks guys.

Also -- ck to see if the LOC is wired in phase ...

this can also cause some strange things to happen

just a thought

Could also be that your used to the bad sound the factory speakers produce. Most factory speakers over do the bass so when you put in aftermarket units you miss that overload of bass from the speakers. Fact is your going to need a sub to get back that bass, those speakers are meant to be used with a sub.  Definately chuck that LOC and wire the factory speaker outputs to the amp directly.  Heck, the output from the factory HU may already be low level so you may be able to put RCA ends on there and plug it into the RCA plugs on the amp!

Check it out, see what you can find.

thanks all.   I know everythin is in correct phase,  I took special care to make sure all "+" and "-"  were matched up correctly.    I paid for and downloaded the wiring schematic of the Durango so I knew what wires were what.

I think I need to eliminate the converter.

Matt