OEM Audio Upgrade - thoughts and opinions

I have on order a 2009 LTZ (due to arrive end of October) with nav (no DVD) and the Bose 10 speaker Centerpoint system. By all accounts the audio quality is only okay. So I am planning an audio upgrade.

What I am planning is to keep the OEM HU and upgrade all the speakers, and sub with these.
Boston Acoustics Pro60 x 4 (or maybe 6)
JL Audio Stealthbox
JL Audio HD600/4 x 2
Rockford Fosgate 3SIXTY.2 (as I am keeping the OEM amp)

One of the questions I'm pondering is that since the OEM system has a center channel speaker for the simulated 5.1 surround, do I replace that with a component or just forget about that speaker in the dash and just mount two components in the rear. The question arises since after replacing the 4 door speaker and tweeter pairs and using 2 channels (bridged) for the sub, I still have 2 channels to play with. Maybe 6x9's in the back?

Another question is that in this thread (http://www.tahoeforum.com/showthread.php?t=9592) details the amplifier connector to have 7 output channels which are all accounted for in the OEM speaker setup. My question is if anyone knows if the individual output channels are all full frequency or frequency limited by the OEM amp? This relates as to whether channel summing will be needed.

Other planned mods are for VizuaLogic A-1290 Headrest Monitors, Passport 9500ci detector, GMPP CAI, Corsa sport exhaust, and a Blackbear tune.

Cheers.

Sounds really good, I want to do a little something to mine too, proabably just LOC for a separate bass channel. The only question I believe I can answer here though is that I think the Bose filters the signal using an individual crossover at each speaker, at least involving the mids and highs.

You are right there are cross overs at the individual speakers. As well the amplifier does auto equalization on all the channels. One good example of the amps 'equalization' is that it cuts the bass as the volume goes up so as to not over load the speakers. This amp equalization is the reason I went with the 3Sixty (CleanSweep would work too) to normalize the frequency (and create proper pre-am signal levels) of all the audio channels prior to sending the signals to the new amps.

DofD said:

...........Another question is that in this thread (http://www.tahoeforum.com/showthread.php?t=9592) details the amplifier connector to have 7 output channels which are all accounted for in the OEM speaker setup. My question is if anyone knows if the individual output channels are all full frequency or frequency limited by the OEM amp? This relates as to whether channel summing will be needed.

Click to expand...

-There's a different amp and a different connector in the 09's.
-The channels are EQ'd via amp's DSP.
-There is clip detection circuitry which compresses the audio waveform. The amp's amplifier devices dissipate only 100W RMS per output at full smoke.

Hardin Thicke said:

-There's a different amp and a different connector in the 09's.
-The channels are EQ'd via amp's DSP.
-There is clip detection circuitry which compresses the audio waveform. The amp's amplifier devices dissipate only 100W RMS per output at full smoke.

Click to expand...

Thanks for the information on the 09's.

So for the moment most of the PAC devices are obsoleted for the 09s.

Would you know if the clip detection circuitry does progressive compression as the amplitude of the wave form approaches the point of clipping or does it just compress at the point of clipping? I guess a plan would be to make sure the gains on the aftermarket amps are set well so that the signal going through the OEM amp won't reach clipping level.

It is progressive. Question: Why go thru the OEM amp? Why not bypass is altogether? They're line level signals upstream from the amp.

I debated the ideas of bypassing the OEM amp and going with the appropriate PAC connectors to maintain the OnStart, bluetooth, chimes, steering wheel controls, etc functionality versus leaving the OEM amp and going with a LOC/signal normalizer solution. A couple things that swayed me away from the bypass solution was that apparently the lux amp does all the pre-amp functions (volume control, fader/balance, as discovered by on 08 Denali owner with the same audio system) and the 3Sixty's extensive equalization options for all the channels.