2011 LTZ bass is gone after speakers replaced

It's the next morning (Tuesday) and I was able to get the 4-gauge wire from the battery to the trunk. Above the spot where the hood release passes through the firewall I drilled a hole, installed the grommet that came with the kit, pushed a string through, and then pulled the cable. It runs along the driver's side all the way to the trunk, but isn't long enough to make it to the right rear taillight where the Bose amp is mounted, which is also a convenient place to find all of the wires. I ordered a 4-ga. screw-type splice and some more cable.

Also ordered was a voltage-sensing isolator relay. My plan is to put my "old" AGM battery that I replaced last year in the trunk so I can have power when I'm out on photo adventures, such as shooting the night skies. It tested with 350 CCA when I was in Philly. (Thank you @Rodents!) Using that should be able to keep it charged and to prevent it from diminishing my main battery.

I think I might have come up with a solution for the concern I posted above about having 6 discrete speaker circuits but only 5 channels on the amp. I will wire the rear speaker outputs to the Rockford-Fosgate crossovers that came with the speakers, then the outputs of those crossovers to the rear speakers and tweeters. Does that sound like it'll work?

I probably won't be able to work on it again until this weekend, and the parts should have been delivered by then.

@le012wf
I guess I got tired and forgot about updating this thread. Thanks for stopping by and helping me remember to add the details.

TLDR:
In short, if I were to do it again, I'd get speakers that are not so ear-splitting "bright", but I'd still have an aftermarket amp and sub-woofer.

Observation:
Remember, though, that all of my work was during Covid-19. I was WFH (working from home). That ended at the beginning of November that year, and none too soon! I was going stir crazy. It felt as though I was locked up since I was WFH for 5 days, and then under heavy travel restrictions on the weekends. I went almost nowhere and did almost nothing. Going back to the office made a huge improvement. But I digress ...

Long version:
My old battery sat around my home for too long without being charged. As such, it is not able to handle any work at all. It's still in my trunk with that voltage-sensing relay hooking it into the main battery so it can get a bit of charge, but it really isn't useful at all. I would get a real battery, but instead my plan is to remove it and keep the 4/0 wire. Why keep the wire? Because my amp needs it.

So, with or without the battery in the trunk, the 4/0 terminates on the left side and the amp is on the right side, in the same place as the Bose amp was. To protect the 4/0 wiring in case of a short, I have a resettable 100A circuit breaker. I can remove the battery at any time and save weight but just haven't gotten around to it yet.

At first, the RF amp wired to just the speakers and I was still getting absolutely no bass at all. Those speakers still don't produce any bass and never will. They are the Punch series with plastic cones, making them very good at being precise and "bright", but terrible at bass.

So I bought a 10" sealed RF sub that is driven off of the dedicated sub-woofer portion of the amp. If memory serves, the 750W amp uses 350W for the sub. The HU still has the treble turned all the way down, the mids are below center, and the bass is all the way up. There is a separate adjustment control that came with the amp that lets me dial in how much bass I get. I have had it in the middle, but am currently running it at full tilt. When there is a song that I want to listen to at high volume, I can't turn it up past about 7/8 or my ears start to hurt to from too much treble. Recall that that is with the treble turned all the way down, too! But with the volume above about 1/2, my inside mirror starts to readjust itself so that I have to keep raising it to see out the rear window. I don't usually drive with it that loud, but there are some songs that really benefit from it. What I'd really like is to have the 4 speakers at lower sound levels so I can turn up the volume to get more bass without making my ears bleed.

When I listen to "Flight of the Cosmic Hippo" by Béla Fleck and the Flecktones, I turn it up. It's made for a sub!

I'm back with an update that I just finished about an hour ago. And boy, is it a HUGE change!

I've been watching YT videos from Car Audio Fabrication. The owner is Mark and puts out really good information. After hours and hours of videos, I finally decided to buy a DSP - digital signal processor. This device does way more than just equalize the output. There are settings for the delay from each input and each output (both Left and Right), signal summing, redirecting inputs to different outputs, and more.

I don't have either of the 2 options offered. I will check the reviews and what they advertise that they bring to my listening experience, but for now, this thing made my day.

Short version: MY SOUND SYSTEM HAS NEVER MADE ME AS HAPPY AS IT DOES AT THIS MOMENT!

Stock photos from Crutchfield's site.



For those still reading, here is a recap of the entire process. For details, look in the thread.

I removed the stock Bose speakers in the front doors and rear deck, removed the Bose amp in the trunk, kept the stock tweeters in the A pillars, then installed a pair of round speakers in the front doors, added round speakers in the rear deck, and installed the tweeters that were included with the front speakers but put them in the back. The speakers are all RF Punch series. Later on I added a RF 10" sealed sub-woofer.

For wiring, there is a 1/0 (one ought) cable from the front with a 100A breaker at the battery, another 100A breaker at the left rear where I used to have a spare battery, then a 100A fuse over to the RF amp. It has 5 channels.

The wires going into the Bose amp were not cut off. Instead I soldered splices into them and ran them as speaker-level inputs. Originally they went to the amp, but now they go to the DSP. I'm using only 4 out of 8 input channels, and only 6 out of 10 output channels (thus the name - 810). Swapping the input wires from the amp to the DSP was easy, and the 6 output channels was even easier - I used paired RCA cables.

The output wires from the amp use the stock wires to the front, which also has its stock crossover to keep the tweeters from blowing up. The new rear speakers and tweeters use completely new wires since it was right there and easy to do. The sub-woofer has 10-gauge wire.

I added the DSP last night (Thursday) after work in less than an hour since it was mostly just move 8 wires (4 channels of + and -), add power, ground, remote turn-on in, remote turn-on out, and the RCA cables.

Tonight I spent about 2 hours learning how to tweak it, clicking the wrong "save" button and losing my work several times, and then getting smarter by using "Save As..." to keep my work. After that, it was a bit tedious, but with this many adjustments I didn't expect it to be quick.

Now that it's done, I am going to enjoy all my tunes and massive amounts of bass at my beck and call.

I can only say that I am more than 100% glad that I bit the bullet and resolved my issue.

A huge Thank You to everyone who commented or even read some of my posts and thought about posting. It has been a journey, one that I did not take alone.