I don't know of this is what is happening to you but..
sometimes when I am listening to a song and a part with some base comes up the audio is lowered for some reason. It does this in my mercedes and pathfinder. So it might just be all cars. If you get a sub though the stress on the speakers for bass will go down and you will get better audio and bass.
hope this helps

 

It's not the head unit. The solution is to replace the amp. It cuts the volume when the dBs get too high to reduce wear and tear on the speakers. Without getting rid of that crap amp, there's nothing you can do.

 

Is it some proprietary amp ? Meaning, can it be replaced with any old aftermarket amp ?

 

I went to several car audio places to find both the cheapest and smartest ways to get some more volume out of this car. Here's what several of them recommended (keeping in mind that I'm not an audio junkie and may get some of the terminology wrong):

- Buy a four channel amp, front speakers (all four), and rear speakers if so inclined (rears were not necessary according to all the places I talked to), and another box that converts the output from the head unit to a signal usable by the aftermarket amp. I believe it's called a 6-channel line-out. Total for all of this was $3000 including the labor, high-quality cabling, and the fabrication of a shelf in the trunk to keep the amp and 'signal converter' up and out of the way. I chose the rather pricey ($800) JL-Audio HD600/4 amp because it was extremely light-weight and performed well. I chose the FOCAL 'medium-quality' speakers... they ran about $800 for all six.

- Run the stock sub off of the stock amp.

- Run all six speakers off of the new amp.

- The audio guys recommended running the stock sub and amp until one of the two ****s the bed. Then, replace both.

I think the biggest benefit to doing it this way is that you retain all of the stock functionality while getting much better sound.

Also, while you've got your dash ripped apart, run some decent grounding to your cig lighter and beef up the quality of cables running from the RCA jack to the head unit. This will reduce all of the signal interference that plagues the AUX in.

 

Interesting...

Wish there was an easier solution than just dropping 3K on a new stereo

 

there is, if you read the whole thing then you would know that he picked some of the most expensive audio options

and you can also do alot of it yourself to save money

 

yeah holy macrel, 3k just to modify the stock setup!

I've got an old skool Rockford Fosgate Punch 200ix kicking around, maybe I can place it on high pass and power everything but the sub in the trunk. It's only a 2 channel amp but rated 240 watts per channel at 2 Ohm Load. I'm not sure if I need a 4 channel amp to keep all the sound effects features of the stock system though.

I'm assuming that if I leave the stock amp to send 100% of the power to the sub it should make that slightly stronger and remove the autoleveling from the main speakers. Likely I'll have to turn down the gains a bit so that the factory speakers don't vaporize though. I'll have to get one of my audio educated friends to see what the best combo would be.