Pretty much as the title implies.... I've got a 2004 Yukon XL, and I'm updating the entire system. Just replaced my alternator with a 253amp model from a 3500 series pickup (factory option! bolted right in!), will shortly be wiring up a second 1000cca battery. Dual 1/0 runs to the rear, fused at both ends. Currently only running (1) amp, and old Lightning Audio 1001.d @ 1 ohm, will be swapping that out, most likely to a Skar RP-1501.D. Two Powerbass S10-d (dual coil) subs in a 2.7-ish cu ft box built into the rear quarter panel. Tuning is way too low, probably about 24-25Hz. Factory speakers in the doors and rear pillars, will soon be changing them out - probably doing a pair of 6.5's in the front doors, a single 6.5 in the rear doors, and a pair of 10" Powerbass S-10's (single coil) sealed in the front portion of my center console as mid-bass, from 60-150Hz. Will plan on running the speakers and front S-10's on a five-channel amp, most likely Skar's AP-600.5.

I've got nothing set in stone for the 6.5's, there are literally hundreds of options - but if anyone has some reasonably priced option, please offer suggestions. My biggest dilemma is figuring out what to put in the rear C-pillars. The factory fill is a 2" or 2 1/2", only about 3/4" deep. I'd like to go bigger, even if it's a 3 1/2" or 4". Would run them in parallel with the rear door speakers, dropping the load down to 2 ohms, the same as the front doors. Has anyone ever seen the C-pillars upgraded/enlarged? I found a pair of PPI Sedona series 4" two-ways, supposedly will handle 60 watts RMS, max of 200 watts. The Skar 5-channel is rated at 90x4 @ 2 ohms, so each would see a safe 45 watts.

Thoughts/suggestions?

Edited January 5, 20187 yr by BigDaddy13440

My first suggestion would be to forget the rear speakers and put that money and effort into the front speakers. Rear fill is simply useless and a waste of money. I had a ‘98 Chevy Venture and people in the back seat never complained about not hearing the highs. 

As for the front speakers, if you run the front doors with a pair of 6.5’s you’re already going to have a 2 ohm load unless you’re planning on using 8 ohm speakers in that location. Secondly the smaller 3.5-4” speakers are never going to handle that much power full range. You’re better off using the freed up (after not going with rear fill speakers) rear channels of that five channel amp to power those separately. Then you can use your HU’s, the amplifiers, or a separate signal processors high pass filters to cross them high enough that the bass and midbass won’t be an issue for them. 

Alton nailed it right on the head. I own 2003 yukon xl and i initially thought what about my rear passengers but i opted to listen to the suggestions and built a rocking front stage. I loved it and you could hear it plenty in the back. So my vote would be rock the front and run it hard.

My Escalade has only fronts.  The rest are all GONE ...and it sounds GREAT in every seat.

The primary reason I've even been thinking about the rears is that I use the truck for work, and usually have the hatch open all the time for access to my tools and supplies. If I delete the rear speakers, then the music has to come from the doors, over the front seats, and through the vehicle before I hear it. I doubt that'd be a serious issue, I could just roll the front windows down, but a lot of the time I have the hatch open when it's raining and I have a covered are to work in (I install doors for Lowe's).

As I said, not a major concern, but if I can easily remedy it, why not? Dual 6.5's in each front door, single 6.5 in the rear door paralleled with the 3.5's or 4's, will have a 2 ohm load of each channel.

Ideally.... I'd love to get some waterproof exterior speakers, and make some swing-out brackets. Have them running off a separate amp (and have switches to shut off each amp), would be great for work (and tailgating!).

I feel that your going above and beyond to remedy a simple solution. Want music in the back for work grab one of them boom tubes and bluetooth to it be done. We want to help you spend smart money and to make the most of it. Rear speakers in any capacity are meh. Or as you stated simply grab some exterior and make a tailgate box. Other than that your same theory for the front speakers is the same problem with the rear. The sound has to travel over the seat through the cargo area. Any speakers past the b pillar is just meh. Focus on your front and you will be happy even in the back sanding down a door cause its a sticky open\close. And throw some good pillar action and you will love life. 

If you want to waste money continue down that path.  Even with the rear hatch open the fronts will do more with the same budget than anything you put in the back.  In particular the rear pillar speakers were always pointless.  Just GM using the "better sound through marketing" nonsense that so many snake oil sales people have used over history.

I too have an 04 Yukon XL and just switched out my fronts and back doors with Pioneer 3 way speakers and also was about to switch out my back pillar speakers but after seeing some of the posts, it makes sense. SWEET! 

Decided to follow the advice given, and negate the rear speakers.

Thanks all!

Nice.  Focus on the front stage.  Take the same money and put it in there for the win!

Friends don't let friends run rear fill 

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http://store.soundsolutionsaudio.com/products/nvx-audio-jad900-5-amplifier.html

http://store.soundsolutionsaudio.com/products/orion-cobalt-cb2700-5-class-d-1-ohm-5-channel-amp-2700-watts-5400-watts-max.html

http://store.soundsolutionsaudio.com/products/sundown-audio-sae-1100-5-5-channel-full-range-class-a-b-amplifier.html