My GXP has the Monsoon system with single CD player. The system is totally stock factory. Audio quality is lacking in two areas. Most noticeable is that the midrange is not smooth. Listening fatigue sets in after only a short time listening to radio, XM, or CD. The center dash speaker appears to dominate the front soundstage. I've noticed a "buzz" from the center speaker that sounds like there is something vibrating off the cone, but I've pulled off the grille and find nothing there. My plan is to replace the center speaker, but I don't want to duplicate the sound quality of that component. Maybe some electrical resistance in series with the speaker leads would help remedy the problem.
Secondly, the bass output from the rear 6X9's is very boomy--emphasis is in the 80-150 HZ bass range, with little or no output below those frequencies. I've considered replacing these speakers, but am aware there is an amplifier with built-in crossover powering these two-way speakers.
In 2007, we owned a new GXP with the same audio system and I remember the same obnoxious sound. Power output is more than adequate--it's sound quality that's lacking. I also have a 1995 Buick Roadmaster wagon that has much better, easier to listen to, sound than the Monsoon system in my Pontiac. Our 2014 Chev SS also sounds much better than the GXP.
Maybe I've not fiddled with the equalizer enough--I normally run the system "FLAT." That yields the least annoying sound.
Has anyone experienced the same? Is there a solution other than new head unit and new speakers? I've not found an aftermarket radio that is compatible with the existing XM system.
