How to add subs to Bose system with Nav

cubangt · September 20, 2021

So I've been reading here and other forums on this topic and still little confused.. So the truck has the Bose stereo with Nav system. So I'm somewhat satisfied with the sound quality, but its lacking that thump, In my past trucks i always had my subs installed and never any problems, but all those trucks and SUV's had the standard stereos, so there was nothing to consider or work around. This truck though seems is more involved in that in order to add some subs, you need to make sure that the amp is wired before the factory amp using certain wiring harness.

So my first question is, has anyone replaced the door speakers with other ones that may be better? Was it worth it? If i did replace them, i would also be doing some sound deadener like dynamat or something similar. In my other trucks, i upgraded the factory speakers with better ones and that alone made a huge improvement.

Second question, does anyone have or know where i can find the specs for the door speakers? And do all Bose systems have a factory amp?

Alec Kerchner · September 22, 2021

I added subs to my new truck last week. It was pretty easy. I have a 15 Denali with bose. For the amp remote wire, i tapped the 12V outlet on the back side of the center console. Its on basically all of the same times that the radio is. For audio, I back probed the amp plug for the front speaker outputs. I used the high level inputs on my amp. I do not know what the colors were, or which plug it was. If my memory serves me right, it was the plug on the driver side of the am, with the thickest wires in it. You will have to google the wire colors for the front speakers. DO NOT USE the rear speakers, the bass is filtered out of them. Ask me how i know. The amp is located on the back wall behind the passenger rear seat. You need to remove the passenger side rear seat for easy access. For power, i found it easiest to drill a hole through the firewall. From the engine side, you will see a black tube coming out of the firewall on the passenger side. To the left of that, there is a small square of insulation missing, thats where i drilled. I drilled from the inside though. It really is about that simple.

cubangt · September 22, 2021

So sounds like you made the sound wire connections in front of the factory amp correct? did i read that part right? What size subs did you go with and im assuming under the backseat is where you placed them? I looked at the low profile 10's that kicker makes, i was hoping to have reused my MTX 10's i loved those in my other cars, but i had room to run those.. I just want to have some good bass in the truck again and dont want to loose any functionality if certain things need to be replaced.

Alec Kerchner · September 23, 2021

I have 2 12" alpine baseline subs. Cheap and get the job done. Also no, sorry. I was half asleep when I wrote that out. I used the speaker outputs on the Bose amp, for high level inputs on my amp. This is the only picture of how I back probed the plug. This was also the wrong plug I think. I tapped the rears at first and then realized the stock amp filters all of the bass out of the rears, so then I tapped the fronts.

cubangt · September 23, 2021

And that connection is the one under the console that connects to the amp correct? Now that the weather is getting cooler, i may finally take a look in the truck at what is envolved and what im willing to do myself. I appreciate the picture and the info on how you did it..

cubangt · October 11, 2021

So i decided to go get a quote for custom box, 2 subs, amp and install at CarToys here in houston and was shocked by the cost..$3200. The installer was talking about tapping into the rear door speakers for the signal for the new amp. And everything i have read and found is stating thats not the way to do it.. I have always installed my own systems with the exception of one car back in the day, but still not sure what the big deal is about having the Bose system and adding subs to the truck.

I was watching some videos this weekend after getting that wild quote and found that there is a harness that you can get that goes in line where the factory harness connects to the amp, allowing all the factory sound to be controlled as is, but then giving you the wiring(ahead of the amp) to run the signal to the new amp and subs without issues or tampering with the factory setup.

The site that i found in most of the videos was this place: https://lljcustoms.com/collections/chevy-gmc-cadillac

The price is reasonable enough to make things plug and play and not cut any wires.

Something else i noticed in a few of the videos was that the boxes were being made out of 3/4" to 1" plywood instead of MDF. Have things changed on box building?

Ive always made my boxes out of 3/4" MDF and never had issues..

And has anyone replaced the door speakers with some aftermarket JL Audio speakers or other brands?

ftwhite · October 13, 2021

I replaced speakers in my 2018 Bose system first. The Bose speakers are really mediocre. However the Bose amp power is weak. So i quickly looked for adding amps for doors. This gave me the biggest improvement, but I didn't like the idea of taping into wire harness because 1) the Bose system is used for environmental sounds (Ringer, door ding, seatbelt reminder) and I didn't really want those amplified, and 2) my 6.2 has a noise canceling system that uses the factory sub and woofers to cancel low RPM engine and exhaust sounds, which I heard can be amplified via a replacement sub.

So I used the Nav-TV M650-GM to interface with the headunit to Bose amp communication channel and send a un-processed complete signal to the aftermarket amps. I then also had a simple way to pull a sub signal and add a second amp and sub. Love the sound now.