Alternate wiring for Kicker sub with Bose system. (DO THIS)

Tjeli · July 30, 2021

Hey Everyone,

I'm posting this in this forum because it is specific to T1 trucks but the same principle can be applied to other years.

First of all I do consider myself an audiophile. Not so much in vehicle systems but I don't want to add up how much time and money I have spent over the last 30 or so years searching for the perfect, limitless, balanced sound in my home systems. If you would like to know what I run at home you can PM me.

Now on to the point. I had some free GM accessory money to use up so I decided to give the Kicker sub upgrade a try. It sounded "ok" and did make quite a bit of bass. I would seem to get it dialed in for one type of music and then it would sound muddy and bloated on a different type. It was also very heavy in the upper mid bass. In case anyone was wondering what the DIP switches do for SURE on the Kicker amp here you go. (I measured them) Switch 1,2 and 3 are gain. There are 4 settings from all 3 down to all 3 up. Switch 4 is the remote turn on selection. Switch 5 turns the crossover on or off. Switch 6 adjusts the slope of the crossover from 24db (on) to 12db (off). I firmly believe that the way Kicker ships these is the proper setting for our trucks. (1,4,5 and 6 up and 2 and 3 down)

One thing that really bothered me about the install of the Kicker sub is that they are pulling their input signal from the right front speaker only. Does the Bose system have a high pass roll off programmed into that channel? What about music that has bass dedicated to the left channel only? What happens when you start to overdrive that channel in the Bose amp?

Say what you will about Bose but one thing they do well is "tuning" a system in a vehicle so that it sounds good at all volume levels to the majority of people. Read that sentence again. This is all done with a LOT of eq, monitoring the amp channels for compression and clipping and attenuating certain frequency ranges at higher volume levels. The result is a system that plays loud and sounds "decent" for the majority of consumers while staying within the budget given to them by the auto manufacturer.

Enough rambling. After a bunch of digging I found the wires that run to the factory Bose sub. I tapped these for the input to the Kicker amp. To my ears it sounds 100 times better. Much more balanced at all volume levels and with all types of music. It is cleaner and hits harder with less overhang. It also plays bass from both channels now. I really have to recommend this to anyone that has the Kicker sub upgrade. Hit me up if you have questions.

-Eli

TSchevy · July 30, 2021

Great information. I’ll attempt this over the weekend. I have been largely underwhelmed by the Kicker system. It’s a nice system, but I have the same complaints raised above.

cltsig · July 30, 2021

What are the wires running to the Bose amp? Any tips (colors)? I had the dealer install mine so I don't really know what they did but likely followed the GM instructions. Would switching it be difficult? In other words, for those with it already in place, what steps should we take to do what you've done above? I know that is asking a lot so I appreciate the feedback.

Rob Mugs · July 30, 2021

4 hours ago, Tjeli said:

One thing that really bothered me about the install of the Kicker sub is that they are pulling their input signal from the right front speaker only.

THIS right here is why I haven't bought one. I couldn't imagine that they were sending a full signal there.

That said, I would be interested in what the lowpass cutoff is at the Bose sub. I think it's a 4"? 5"? I imagine they'd be cutting the signal around 80hz or so? Hard to think they'd be pushing say, 35 hz to that little guy but is probably within spec for the Kicker.

If you have a scope, would be interesting to see where it tapers off

Rob Mugs · July 30, 2021

Sidenote.. not an audiophile ...

Running Klipsch KLF30s alongside SVS PC-4000s (yes.. plural)

Tjeli · July 31, 2021

8 hours ago, Rob Mugs said:

Sidenote.. not an audiophile ...

Running Klipsch KLF30s alongside SVS PC-4000s (yes.. plural)

there’s more than one SVS in my main system.

Edited July 31, 2021 by Tjeli

Tjeli · July 31, 2021

8 hours ago, Rob Mugs said:

THIS right here is why I haven't bought one. I couldn't imagine that they were sending a full signal there.

That said, I would be interested in what the lowpass cutoff is at the Bose sub. I think it's a 4"? 5"? I imagine they'd be cutting the signal around 80hz or so? Hard to think they'd be pushing say, 35 hz to that little guy but is probably within spec for the Kicker.

If you have a scope, would be interesting to see where it tapers off

I can measure it if you want but my guess is that there is no high pass on the sub channel. The Bose sub is a sealed design that has a natural roll off of almost 24db per octave below its tuning frequency. (Which I believe to be around 50Hz). There really wouldn’t be a need to set a high pass or “ subsonic filter” for a sub like that.

With all the being said, to my somewhat trained ear the channel will reproduce at LEAST down to 30hz. This is lower than 95% of the music spectrum.

like I said in my original post…… I am not into hard core car audio. I just like my music to not sound like crap when I get in one of my vehicles. The mod that I outlined in my original post was almost like a breath of fresh air after I did it. Everything just sounded “better”. YMMV

Edited July 31, 2021 by Tjeli

Rob Mugs · August 1, 2021

22 hours ago, Tjeli said:

I can measure it if you want but my guess is that there is no high pass on the sub channel. The Bose sub is a sealed design that has a natural roll off of almost 24db per octave below its tuning frequency. (Which I believe to be around 50Hz). There really wouldn’t be a need to set a high pass or “ subsonic filter” for a sub like that.

With all the being said, to my somewhat trained ear the channel will reproduce at LEAST down to 30hz. This is lower than 95% of the music spectrum.

like I said in my original post…… I am not into hard core car audio. I just like my music to not sound like crap when I get in one of my vehicles. The mod that I outlined in my original post was almost like a breath of fresh air after I did it. Everything just sounded “better”. YMMV

Thanks for that. It's been a few moons since I set up anything in car audio myself. 30hz would be plenty more "oomph" to this system which consists of mainly mid-bass.

jeepincbum11 · August 2, 2021

On 7/30/2021 at 1:25 PM, TSchevy said:

Great information. I’ll attempt this over the weekend. I have been largely underwhelmed by the Kicker system. It’s a nice system, but I have the same complaints raised above.

Did you do this? How did you make out? Might have to do the same for mine as i tapped into the wires under the passenger door sill.

jeepincbum11 · August 2, 2021

On 7/30/2021 at 10:30 AM, Tjeli said:

-Eli

Eli - What am i looking at here? Drivers side or Passenger side? i am assuming passenger right?

Edited August 2, 2021 by jeepincbum11

Tjeli · August 2, 2021

55 minutes ago, jeepincbum11 said:

Eli - What am i looking at here? Drivers side or Passenger side? i am assuming passenger right?

Sorry. Yes. Passenger side. You have to pop the side of the console off. The wires run up right behind that metal console bracket.

-Eli

Mudcon · August 3, 2021

On 7/30/2021 at 10:59 PM, Tjeli said:

there’s more than one SVS in my main system.

Love my 2 svs pb16 ultra's

TSchevy · August 4, 2021

On 8/2/2021 at 9:05 AM, jeepincbum11 said:

Did you do this? How did you make out? Might have to do the same for mine as i tapped into the wires under the passenger door sill.

I got it all taken apart…realized I have no spare wire. Will complete the job tomorrow. Wires were easy to find behind the passenger side console plate as TJ mentioned. I used 14-16 T-taps. I’ll follow up upon completion…

Tjeli · August 4, 2021

14 hours ago, TSchevy said:

I got it all taken apart…realized I have no spare wire. Will complete the job tomorrow. Wires were easy to find behind the passenger side console plate as TJ mentioned. I used 14-16 T-taps. I’ll follow up upon completion…

Please do.

Tjeli · August 4, 2021

Update to my update. I was running my “bass” eq at -2. This seemed to take a bit of the soundstage and mid bass out of the front. I pulled the kicker amp and out switch number 1 down. So 1,2 and 3 are all down. I am now running the bass eq at +2 and things sound even better. My personal settings are +2, -2, and +12.

I also measured the sub channel. There is useable output at 30hz. The signal is still there at 20hz but the output is down over 12db. This sub is not designed to play that low. One of these days if I am extremely bored I will pull out my good measuring equipment and plot a response curve.

-Eli