Added Nav, Now No Bass?

[yettavr6]

Hello all, this is my first post on here since buying my 2007 GMC Sierra 2 weeks ago.

 

I just installed a brand new OEM nav radio in my truck. It is an SLT so obviously has the Bose system. While i wasn't completely impressed with the Bose system to begin with (especially considering its 345watt rating, compared to the 180watt Bose system in my Audi), it now completely lacks bass at high volumes. It is pretty obvious to me that the headunit is turning down the bass the higher I turn the volume. I have to max out the bass to have any at high volumes, which makes the bass overpowering at low volumes. It was not like this with the 6-CD MP3 headunit. Does it sound like something needs to be programmed? I didn't have the dealer do any programming as the unit was not theftlocked, and everything else seems to work, including the chimes. It even shows "Sound by BOSE" on the splash screen. Doesn't that mean that it is already programmed for the Bose system? If so, is there any way to disable this auto EQ? I know on the Audi headunits they do the exact same thing with limiting the bass at higher volumes, but that is only on the base system. On the Bose system the headunit does zero equalization, as it is all done by the Bose amp...at only 180watts I can't believe how much better Audi's Bose system is, paper cones and all. Even the Pioneer system in our HHR sounds ten times better now...

 

Any suggestions welcome! (besides replacing the Bose system, which i don't think would help since it seems the headunit is to blame)