First I want to thank the pioneers that posted their audio experiences to this forum. This is the only source of reliable information I found on this subject.
So to show my appreciation, I would like to share my contribution with the group. At the bottom of this post is a wiring diagram of my current installation.
Here are some threads loaded with good information:
Guide on how to add a sub to a 1SS nonBOSE system
Full Stereo Upgrade Build on 2SS with Bose
Here is my story...
Before trading in my '13 1LT I needed to pull out the audio system that was installed an put it in boxes. After some listening to the Premium Bose System
in the '17 my thoughts were that it's not bad for a stock system. The things it lacked was the punch of a real sub woofer and overall clarity. Let's face it,
you can't do much with 3 bands of equalization.
My goal was to enhance the stock system with the high end components in the corner of the living room without tearing off door and dash panels. I did
that with the '13 and was trying to avoid it. I put the sub box back together and so in begins.
Phase 1
With the sub, I wanted to be able to lift it from the floor so I could get the mats out and access the trunk well. I picked up some tie down straps and
hooked them to the rear deck frame to create a hoisting device. I hooked the battery up to a capacitor which feeds the power to the sub amp. I took the
speaker signal from the rear deck speaker contacts in the trunk. This was only temporary but served as a quick test to get a signal and see what I was
dealing with. It lasted about two minutes before the noise cancellation feature made this unbearable. So I disconnected the speaker connection and
jumped on the forum.
Phase 2
I learned that the X3 plug needs to be pulled from the stock amp to defeat the built in noise cancellation. After I decided which stock speaker outputs to
tap into, I found a spot to test the tweeters. I had a little luck, the Hertz HDP4 I have fit perfectly in the styrofoam tray in the trunk well. I tapped into
the front left and right speakers output wires for the audio source signal. I placed the tweeters in the child restraint cut outs in the back dash and wired
them to the amp via the passive crossover. With this configuration there was no significant gain with the tweeter since they were physically too high and
angled toward the headliner. I didn't expect anything spectacular but at least I had sound. I was able to tune the sub amp and get a good baseline.
All along I'm thinking of a location for the 6.5 inch woofers...
Phase 3
With the idea in mind to leave the stock system intact, the only available space for the 6.5" speakers is the trunk space behind the back seat and in
front of the sub enclosure. So I started planning an enclosure to house the woofers and tweeters.
There is only 22 inches of usable width so the speakers needed to be angled to the outer sides of the front seats for better stereo separation
keeping the direct reflecting concept in mind.
It wasn't easy to secure the panels in place since they are angled to the sides and tilted back but I found a way. I put foam baffles behind the woofers
but the wire would vibrate against the foam pretty bad so they were later removed. (These baffles actually were the motivator to build a box)
I realized after hearing the subs and tweeters that the only way this would work is with a decent DSP. I had an Audison bit Ten D that I fried in a
previous experiment. I went back to my dealer and he had the same unit which was a display model so I got it from him cheap. He had a different unit
there new for about the same price but I knew that if I were to have a chance at blending this in with the stock system I needed a DSP with the
tuning capabilities like that of the Audison.
So I got everything wired and left the new enclosure outside of the car to start the initial testing since it would be easier to fix any issues that way
before putting it in the car.
This is the one thing I learned that I did not know beforehand so this is probably the most valuable contribution of this post if anyone runs into a
similar issue.
The DSP is capable of using the signal inputs as the remote turn on of the unit, which relays that signal to the remote inputs of the two amps.
Well, whenever I put the head unit above half volume the DSP went into protect mode and the Hertz amp indicated over voltage. Since an increase in
volume amplified the remote signal I assumed this was causing the issues. So, I jumpered off of the wireless charger fuse as was pointed out in one of
the referenced threads above and that solved the problem. I would like to find a better remote signal but this is it for the moment.
Once everything was getting the proper signal, I put the enclosure in the car and hooked it up. Then I spent about an hour tuning the system. I went for a
long cruise the next day and started the tour with some Rob Zombie. This experiment was well worth the effort. I could not believe what I was hearing.
I think this is what the artist intended it to sound like. Imaging headphones that wrap around your whole head. That's the best way I can describe it. By
filling the cabin with the weak frequencies of the stock system, I can reduce the bass on the head unit which actually puts less strain on the front
speakers while letting the new components do their job. On some types of music I found that fading to the back 2 or 3 steps gave great results. For
other types fading all the way to the front was the answer. This actually sounds better than what I had in my 5th gen so to all those audio salesmen
telling me that there is no need for rear speakers, I call bull$h!t...always have.
I will be keeping an eye open for a compatible MOST interface capable of sending the audio signal before the amp, to the optical input on the DSP...
I promise...I'll get those wires cleaned up!
Current setup
