Stock head unit sounds way better than aftermarket hu does

[Roush87]

I have a 2005 silverado ss with bose and have an alpine cda 105 hooked up instead of the stock hu and noticed that the sound quality ***** compared to the factory hu. I have the metra gmos -4 wiring harness to keep chimes and on star but I'm wondering if that interface is what's causing my problems. Anyone else had this problem before ?

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[Hunter0811 10+ year member]

Most GMOS-04 units have a potentiometer on the side, to adjust for the factory amplifier input. Have you adjusted that yet?

 

[bradl79 10+ year member]

i noticed my stock HU had better separation than my clarion NX702 HU

 

[Roush87]

Most GMOS-04 units have a potentiometer on the side, to adjust for the factory amplifier input. Have you adjusted that yet?

The only potentiometer I see on there is the one to adjust volume for the chimes I didn't notice any difference when I turned it except for the chimes got louder no difference in music.

 

[Hunter0811 10+ year member]

Ah then that would mean you have the newest version of the harness which does not use low level RCA from the source unit. I have actually had some issues with those since the switch. On the bright side, they seem to have less issues with alternator whine (not uncommon for the stock Bose system). My next thought would be a better quality line level controller like an ISVE61 just for the stock amplifier inputs, however the Onstar and chimes put a dent in that idea. That would give you the ability to fine tune it rather than being stuck with a default setting. I'd be tempted to try an older GMOS harness with the RCA's, but be prepared for ground loop isolators.

 

[keep_hope_alive Premium Member]

yep, you need better interface between the aftermarket HU and the factory amplifier. you'll only be as good as stock can be since the new HU isn't doing any actual amplification.

work on level matching between the aftermarket HU and the adapter (whichever works best with your vehicle). that will determine the max usable volume on the HU and allow you to give the factory amp a good signal.