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2011 LTZ bass is gone after speakers replaced

6430 Views 31 Replies 8 Participants Last post by  Jawkn333
Note: Long post.

Well, I had been on the fence for a long time and finally decided to replace the 4 speakers before they decided to fail. They seem to be a common issue with enough and so I thought that prevention would be better than a cure. Well, this "physician" can't heal himself! :eek:

I chose Rockford Fosgate speakers for all 4 corners. I decided to go one step above basic and got their Punch series. For the front door 6½" speakers it was a choice of 6½" or 6¾", with the larger ones being 3-way and the smaller being 2-way, so I took the 3-ways for the same price. For the rear 6" x 9" I got the 2-way speakers.

I have the electrical drawings and carefully tested one of the 6x9 speakers on the left side by using jumper wires. Since they are 2-wire speakers with a built-in crossover and the stock Bose setup uses 4 wires, I was not able to get them to make enough sound. I even tried bridging them and they just didn't do it. I sent them back and got a pair of 2-way 6½" with separate tweeter and external crossover.

The speakers I now have are still all RF: P1675 in the front doors, P165-SE in the rear deck. (I returned the set of P1692 speakers.)

I just finished installing them today after getting the driver's door done Friday night. After getting it installed I was not all that thrilled with its sound output at all. I finished installing the left rear and it, too, was way too light on its bass. I figured I'd just finish all 4 and see if the Bose amp was somehow limiting what it outputs, kinda like the "weakest link" syndrome where the last original speaker was keeping them from making some noise. Nope, that didn't do it.

So here's my dilemma: I have absolutely no bass unless I turn it all the way up and drop the midtone and treble below center.

With all three settings in the center, I have to turn the volume up scary high just to hear a little bass, but then my ears are bleeding from all the SPL of the high notes. I've tried it on a USB file of several of Roy Orbison's songs as well as the SiriusXM tuner coming in on my Aux Input jack.

When I still had at least one stock speaker installed, I could run the fade/balance to that speaker and get deep, warm bass from it alone, but none of the others produced anything at all like it. And still don't!

The only good side in all of this is that I can now hear Roy's words much more clearly than the muddled sound from the stock speakers.

Can someone (or someones) help a fella out?
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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.
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Well guys, here it is a day off and I'm ready to install my 5-channel amp to replace the Bose amp in the trunk. I've confirmed all of the wiring to the speakers, etc, based on a set of drawings that I've had for years.

The replacement amp has outputs for 4 channels plus a sub. I don't have a sub. However, the Bose system uses the rear 6x9 speakers as "subs" and the speakers mounted inside the cage as speakers. The Bose wiring has 6 separate wiring paths, not 4 or 5. I knew this before but didn't think about it until now. (Yay, last-minute preparation! :eek:)

Should I take the output from the sub channel and wire the new rear speakers (already installed a month ago) as the "subs" kinda like the Bose did, or come up with some other solution?

Edit: Added images.

I understand that Bose used the 6x9s as subs, but, for giggles, can you try temporarily connecting the speakers using the sub channel output (to see if your bass returns)? Keep the volume low when you fire up the system in case of any unexpected 'malfunctions'.

I'm curious to see if that will retrieve your missing bass.... if it does, where you go from there... ?
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I understand that Bose used the 6x9s as subs, but, for giggles, can you try temporarily connecting the speakers using the sub channel output (to see if your bass returns)? Keep the volume low when you fire up the system in case of any unexpected 'malfunctions'.

I'm curious to see if that will retrieve your missing bass.... if it does, where you go from there... ?
I finally have all of the parts I need to finish the amp install. At least I hope I do. I intend to do the remainder of the installation this weekend, which includes that second battery mentioned above.
I finally have all of the parts I need to finish the amp install. At least I hope I do. I intend to do the remainder of the installation this weekend, which includes that second battery mentioned above.
Good luck!
Old post I know, but I had the same issue. My wiring adaptor was the same unit for my 08 cobalt. It has a door chime module attached, and a switch labeled "bose" and "non bose". Once I switched the switch to "non bose" the bass was back in the deck and door speakers
Have any luck finishing your install? I am going thru a similar problem.
I’m in a bad place with the wiring. My brother in law said he was installer for years and installed some infinitys but he cut the OEM plugs out and left the low end wires just hanging. It’s sooo upsetting. my son could’ve done a better job.

If you could point me in the right direction DD I’d certainly appreciate it! Also does anyone have a picture of the original wiring so I can figure out colors are the high and low channels + and - I’ve looked around but can’t find anything that seems to jive with the wiring I have

2008 LTZ 3.6

Thanks a bunch u guys are the best!
I guess I got tired and forgot about updating this thread. Thanks for stopping by and helping me remember to add the details.

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.

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! :cool:
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Have you tried fading it all to the front or rear and adjusting the balance to just one side to see if the bass improves? If so, the speakers are out of phase with each other where one speaker cone is being driven out on one channel while the other channel is being pulled in.
I've done that, but it was some time ago. It's easy to do, so I'll do it today on my way to work and then on my way home.

One thing I noticed, which tosses a new Monkey Wrench into the whole mix, is I removed my second battery, which I had meant to do for a while, now that I have an older SUV for running around on the weekends. It was in bad shape. It had a smart battery isolator that charged it when the engine was running and then disconnected it when its voltage dropped below a certain threshold. I could hear the relay clunk off only seconds after turning off the engine. Now that it's out of the picture, there seems to be just a bit more depth to the overall system, but it still lacks bass.

Thanks for the input!
Well, I tried it.

All 4 speakers seem to be putting out more bass than before, but not as much as one would want in a normal system.

I tried each corner individually, then went to the trunk and popped the breaker for the amp. Everything went quiet, so I'll have to experiment by removing the output to the sub-woofer and try again.

So, without worn-out battery in the system, it seems like it perked up the bass a little. I'm happier, but still not overjoyed. The EQ controls, for what they are, are set as follows:
  • Highs: all the way down
  • Mids: a little left of center
  • Lows: all the way up
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.


Stock photos from Crutchfield's site.
Slope Font Audio equipment Rectangle Electric blue

Computer Personal computer Touchpad Computer keyboard Peripheral

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.
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OK, new update, but it keeps getting better!

I was really enjoying my much improved sound but noticed that my turn signal clickers and all of my chimes were so weak that they were almost gone.

The fix was to reinstall my Bose amp, then use the outputs from it to go into my DSP, and then send those out to my amp, and now I not only have my chimes and clickers, but with a little tweaking of the adjustments, it sounds even better!

I'm not sure if I can stand so much good news. :D
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That is good news Driven Daily!
My stereo wiring adaptor harness has a small speaker that those noises volumes are adujustable. My turn signal is irksome waiting in traffic. I have it turned down myself just loud enough I can notice the door ding. Its one of my favorite features!
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