I just purchased a new HU (Sony DSX-S100) for my 2004 Dodge ram 1500 4 door and a pair of alpine 6X9 (SPE-6090) for my front doors (the stock infinity 6x9's were completely blown. I installed them right in place of the stock ones with the stock wires that were already ran through the doors. I believe alpine is a good company and the speakers have good reviews but there really isn't that good of sound quality coming from the speakers.. sounds muffled in a way?? I feel like something isn't right and they could sound a lot better.. Do I need to run the speakers to an amp to get better sound? or maybe change the LPF & HPF settings on the HU?
The Alpine SPE-6090 Speakers are rated for 75 Watts RMS while your Sony DSX-S100 is only supplying 17 Watts RMS.
If you want to get your Speakers louder, your going to have to throw in an Amplifier to supply the correct amount of Watts RMS for the Speakers.
Also something else you can do, is check and make sure you did not accidentally reverse the polarity of the Speaker Wires when installing the Alpines. Correcting this may slightly increase the performance of the Alpine SPE-6090 Speakers.
You can attempt to mess around and adjust the settings on the Deck to try and achieve higher sound output and performance, but you will never be getting the true potential out of them until they are given more power through an Amplifier.
A good 7+ band EQ might help. I only mention this because you don't talk about loudness but more or a sound quality issue. My Pioneer Premier DEH-P960MP Has a built in 13 band EQ and I will never go without an EQ again! With an EQ you can tweak to you liking and your vehicles acoustics as well as speaker placement. JMO
you bought a sony head unit (yuck) and the lowest line of alpines available (type E).
If you want an improvement over stock, get a small amplifier to drive the speakers instead of the 12-15 watts you get from that head unit (any head unit really( and consider upgrading from type E to type R speakers.
I'd also suggest you avoid an EQ. An EQ is a band-aid fix, and it will introduce as many issues as it fixes, such as phase shift and coloration to the original source signal. Better off just adding power to the speakers, and having better speakers, if the power doesn't help as much as youo'd hoped. 45 watts RMS per speaker would be sufficient for a vast improvement over the head unit's internal power. Also consider adding a small sub to give you some low end.