gmdriver

Hi, I'm looking to talk to anyone that might have worked on (either modified or disassembled) the Pioneer premium 7-speaker audio system with XM radio and On-Star to do some fact checking on this system on either 2007 or 2008 Cobalts (or even Pontiac G5s).

* The Pioneer 10 inch subwoofer installed in the trunk is a dual voice coil subwoofer, which is in fact supposedly driven by TWO mono-bridged power amplifier output channels from the Pioneer multi-channel power amplifier mounted around the left underside of the instrument panel. Has anyone actually removed the Pioneer 10 inch subwoofer and/or have traced the speaker cables from the Pioneer power amp and noted 2 pairs of positive and negative speaker cables going to the subwoofer?

* It seems to me that the Pioneer premium audio system actually really refers to just the extra multi-channel power amplifier and 7 Pioneer speakers installed in the car, but that the head unit is really a higher end model of the Delco CD receiver head unit found on the base models. On Cobalts / G5s that have the Pioneer premium audio system, the head unit actually only outputs 4 channels to the Pioneer power amplifier. These observations brings up several questions:

1. Whether the head unit alone is really just a Delco CD receiver unit and is not Pioneer OEMed. The CD transport mechanism is certainly slow in disc handling and not very quiet, compared to many Pioneer CD receivers I've used in past years that have very quick and quiet disc handling.

2. Whether the head unit is actually outputting speaker level output (i.e. the head unit has on board power amp which can be used standalone in a regular 4-speaker set up without the Pioneer multi-channel power amp), and that the Pioneer power amplifier is just a power booster amplifier as opposed to a true power amplifier taking line level inputs. The answer to this question would affect whether the existing Pioneer power amp could be used with aftermarket head units or not, since most aftermarket head units output line level voltage at the RCA jacks.

3. Where the crossover network for the Pioneer amp / speaker system is. For the front speakers, it would appear it's just a passive capacitor type crossover for the tweeters and the front door speakers are outputting full frequency range unfiltered. This observation is made based on the fact that in the Pioneer premium system, the front tweeters and front speakers are all driven from the same power amp channel output, so any crossover network has to be external to the Pioneer power amp. For the rear speakers and Pioneer 10 inch subwoofer, it would appear the crossover network is in the power amp because the Pioneer power amp uses the rear speakers output signal from the head unit to drive both the rear speakers and the subwoofer.


I'd be interested to hear from anyone who has worked more closely with this Pioneer system to confirm the above. Thanks.

EmperorJJ1

iTrader: (5)

Stock sub is indeed a dual 2 ohm sub running off 2 channels of the amp. Crossovers are NOT passive and i dare someone to prove me wrong (i yanked every bit of that speaker wire from the speakers to the stock amp -the molex plugs up front)

Stock amp is a 6 channel and its wired as follows
2 channels for the tweeters
2 channels for the front midrange 6.5s
last 2 channels are for the 6X9s AND sub

how they get the last 2 channels working is beyond me... unless theres a crossover inside the stock sub box but i doubt it


Hu is infact different. who makes them i dont know and dont care but the pioneer hu has line level instead of speaker level outputs. Several members experienced this putting one in an LS including myself

gmdriver

Thanks for your reply and info. I was wondering for what year car are your findings for the Pioneer premium audio system from? According to official information previously released by Pioneer for the Cobalt's custom audio system, the Pioneer 6-channel power amplifier is wired to the speakers just as you described. When I first read this information, I had the impression that the front tweeter signals had already been processed before exiting the power amp output, either by a separate crossover (either preceeding or following the amp) or a crossover (which could still be simple passive components) on-board the amp (for compactness by integrating the crossover network as part of the Pioneer amp's enclosure).

However, in reviewing actual wiring information from GM for 2008 models, a different wiring arrangement emerges, although I'm not sure if your findings are for the same year as what I reviewed. Basically, the block diagram of the Pioneer 6-channel power amp does show a single common output line one each for both front channels driving all front speaker components - woofer and tweeter, wired in parallel, so this arrangement must suggest a post-amp and likely passive crossover (possibly a simple capacitor preceeding tweeter input). This could be a recent modification that was implemented to simplify the amp / speaker (including subwoofer) subsystem. What I found is that for 2008, the amp to speaker wiring is 2 channels for front tweeter / woofers, 2 channels for rear speakers (6 x 9 inch) and 2 channels for the dual voice coil Pioneer 10 inch subwoofer.

So if I understand you correctly, the head unit on cars with the Pioneer premium audio system (whether the head unit is made by Pioneer or not), does output line level voltage. If so, this suggests the Pioneer 6-channel power amp is a true power amp and not just a booster amp that boosts speaker level input. That seems to be encouraging as it might be possible to continue to use the Pioneer 10 inch factory subwoofer and the Pioneer 6-channel amp just for amplifying subwoofer line level signals that could be drawn from an aftermarket head unit that outputs line level subwoofer signals.

But I would be interested to hear which year your findings / observations are based on. It's possible there were minor modifications to the Pioneer amp / speaker configuration over time with different years. Thanks.

EmperorJJ1

iTrader: (5)

never looked at any new info after finding out for my 06 so i would say my info is from ~mid 07. They may have changed things from 06-06 but from both gm and pioneers stand point it doesnt make sense. removing 2 wires to add a cap after the stock amp doesn't really save money if the amp is the same. Also the amp isnt 1 ohm stable so i dont think they wouldn't be able to wire it up in that fashion (cap may give the amp a false 2 ohm signal but not sure) Also if the amp is already actively crossed over using 4 channels any passive or wanna be active crossing with 2 channels doesn't make sense. So while it is possible theres been changes they would be something bigger then eliminating 2 wires

gmdriver

I hope to verify the power amp to speaker wiring configuration in the near future when I get to remove the door trim panels on the front doors. Since you have a 2006 model, and you obviously have the Pioneer premium 7-speaker system, is the shark fin (where the Pioneer tweeter is mounted) above the main door trim panel PART of the whole door panel or is it a separate piece from the main front door trim panel? In other words, when you remove the main door panel, is the shark fin attached to the door panel or needed to be removed separately?

As far as who makes the head unit on the Pioneer enhanced audio systems, I may get to try out the CD receiver head unit on a base model, which is made by Delco as far as I know. I think if the CD loading mechanism sounds and acts pretty much the same as the Pioneer enhanced audio system, then it's probably a Delco OEMed / assembled system as opposed to a Pioneer made system. I'm sure the actual CD transport in the head unit is made by a manufacturer other than Delco, but I'm inclined to expect that I would not be surprised if the head unit was non-Pioneer manufactured.

EmperorJJ1

iTrader: (5)

mind you swapping a lower end radio with speaker level outputs instead of the line level may decrease SQ by overdriving the stock amp

yes the shark fin is part of the door panel for all pioneer peeps but not for the other models. I actually custom fitted the blank LS fins on my door panel and mounted my fosgate tweeters there

gmdriver

What I meant was that I would only use the Pioneer 6-channel power amp for driving the Pioneer custom 10 inch subwoofer. Once the stock head unit on the Pioneer premium system is removed and an aftermarket unit is installed, the front and rear speaker outputs on the aftermarket head unit itself will be used to drive either the stock Pioneer front / rear speakers, or more likely, my preferred aftermarket speakers I will put in. Huge volume is not a priority in my particular plan, so I actually don't plan to drive the front and rear speakers using an outboard power amplifier. Pioneer's aftermarket head units have front, rear and subwoofer pre-outs now, so I would just input the subwoofer pre-out into the rear channel line level input of the Pioneer multi-channel stock power amp, and that should do the trick, though the stock Pioneer power amp's 12 volt power line is switched by the stock head unit, so I'm thinking that the problem could be solved by patching in the power amp's 12 volt DC line into the same power line as the aftermarket head unit would use and that should solve the problem.

What I'm still unclear however, is at which point the car's system chimes (door chimes / turn signals) is injected into the stock audio system's signal path, and whether it's inputted at the head unit level (I know the On-Star mono audio signal is) or the power amp level. If the ignition is in the off position, the power amp is supposedly powered off, so how do the chimes get amplified in the driver door's woofer, that's rather curious.

EmperorJJ1

iTrader: (5)

the stock amp uses accesory power... so care doesnt have to be on for the amp to be on. and all u would need to do to keep the stock amp running is hook up the remote wire on the harness... It would also be easiest insall wise to just extend the speaker wires off the aftermarket HU to after the stock amp and tap the speaker wires at that point along with cap off the wires coming out of the amp

gmdriver

Yup, I agree with your scheme for the speaker wires. I'm planning to use the factory installed wires and probably make my own 8-pin connector for the speaker wires from the aftermarket head unit to the factory speaker wires. That way the original Pioneer stock power amp could be easily reconnected to the factory speaker wires by unplugging the custom made 8-pin connector to the stock amp's speaker wires to which I'll also add another 8-pin connector.

I'll keep in mind your power line suggestions when I get around to replacing the stock audio system. Right now it's all in the planning and evaluation stage to determine the procedure and materials needed for minimal modification to the car's wiring and make maximum use of its existing audio equipment already installed, like the Pioneer power amp and enclosed subwoofer. Saves me a lot of trouble, headache and cost to buy a separate power amp, subwoofer and enclosure for a bit of extra low end bass.

EmperorJJ1

iTrader: (5)

get hertz componants up front and i they can get pretty close to having a sub

gmdriver

By the way, for 2008, the Pioneer power amplifier is supposed to be under the instrument panel on the left side. Is that the same location as yours and did you have to remove the dash to access it or the amp was visible / accessible from the underside of the dash near the pedals? I'll be checking it later in the day. Thanks for all your input so far.

Darkfuzion

iTrader: (1)

i have a 08 t/c is there another pioneer sub out there that they make that will fit on the right side of the trunk?

EmperorJJ1

iTrader: (5)

nope

nope dash didnt have to be removed... bitch to get to btw

Mike Starr

I am looking at removing my sub and amp before I junk my old 2008 cobalt. :-( I was hoping to give my camper's stereo some much needed bass. You say it is line level inputs for the amp. Can I still run speaker level as that is all the camper has. Or am I better to look for a new amp that allows speaker level

EmperorJJ1

iTrader: (5)

id get a new amp. maybe save the sub/rear speakers if you wanted but the amp wont work well with speaker level inputs. Plus you probably could use without the built in crossover point (in exchange of using a different one