I'm not asking any questions here but wanted to offer some information that I have had trouble finding on the internet. This is a long one so pull up a chair…. Please be advised that this post covers what I did in my Armada. In no way am I liable for expenses incurred if things do not work properly or components are damaged as a result of your installation. This post is simply a recap of what I did for my Armada, you will be using this information at your own risk. (gotta love sue happy America)
I recently bypassed the factory Bose amp and upgraded the factory Bose speakers in my 2017 Armada, so I know the factory system pretty well now. I'm a commercial electrician by trade, so thanks to that, lots of internet searching, and some trial and error, the facts I found are as follows. I will also explain how I kept the impedance balanced as the Armada has an odd number of speakers.
The Bose system comes with (13) factory installed speakers:
Front doors - 6x9 mid range
Front Dash - 2 1/2" mid range tweeters
Front Center - 3 1/2" mid range
Back doors - 6 1/2" mid range
Back Doors - 1" tweeters
Back Ceiling - 3 1/2" mid range (same speaker as the center channel speaker)
Subwoofer - (2) 5 1/4", 2 ohm speakers (they use 2 ohm woofers so the amp will be able to send them the most possible power)
They are all located under the corresponding speaker grille except for the subwoofer which is behind the luggage compartment side panel, drivers side
I’m going to explain the install / re-wire step by step. and provide an explanation of speaker impedance and why it’s important to understand what it is and how to calculate speaker impedance. Speaking of impedance (measured in ohms), this is where it gets tricky. The factory installed Bose amp uses a standard 4 channel input configuration, but it has a separate output channel for each speaker EXCEPT the back door mid / tweeter combo which has a single feed for each door. What this means is that you can't just install a standard 4 channel amp and wire everything in parallel because it will drive the resistance for each channel below what most aftermarket amps will handle. This is where most of my research came into play. Let's start with the basics:
If I wire speakers in series, my speaker impedance adds up. For example, if I wire (2) 4 ohm speakers in series I get an impedance of 8 ohms. (positive from the amp or receiver connected to the positive terminal on the first speaker, from the negative terminal on that speaker to the positive on the next speaker, and from the negative on that speaker to the negative for that channel from the amp or receiver) If I wire the same two speakers in parallel, (multiple speakers connected to the same positive and negative wires as a group) I get an impedance of 2 ohms.
*series - R1+R2 = R total
*parallel - R1/# of speakers (be advised this only works if speakers have the same impedance rating. If they do not I would need a different formula.
*parallel with different ohm ratings -
When upgrading the factory amp and speakers, and using the existing wiring to each speaker, I needed to use all 3 formulas to keep my amp stable. Most modern amplifiers are stable down to 2 ohms, but I always check the rating to be safe as some of the speaker combo's in my Armada with take my amp to that level of impedance. Taking just about any amp below 2ohms will damage it, or you'll get a ton of clipping (sound cutting out or distortion and very weak performance).
I have attached the entertainment system wiring diagram for the 2017 Armada, I would imagine it would be good for the next couple model years as well. I used the color codes and planned my installation carefully. This is a big project with lots of connections so I wanted to be sure I did it right the first time. I made a harness of (10) large gauge speaker wires, marked them 1-10 (8 for in/out channels, 2 spares), and ran them between the factory amp location (behind the luggage compartment side panel, passenger side) and the location I chose for the amp (under storage compartment lid in luggage area). Below are the wiring assignments I gave to each of the (8) speaker wires in the new harness.
You can see that there are multiple wires with the same number. I didn’t need multiple wires for each number, I'll explain that later. To start, I went with a 10 wire (2 conductors per wire, + and -) harness, leaving access open after they are installed on both ends. The colors represent the factory wire color in the factory amp harnesses.
BEFORE I STARTED I DISCONNECTED THE BATTERY SO THERE WERE NO SHORT CIRCUITS OR AIRBAG DISCAHRGES WHEN WORKING ON THE ELECTRICAL SYSTEM. After the side panel of the cargo area was off, I needed to remove the 4 bolts mounting the factory amp, unplug the 2 wire connectors from it, and remove the amp completely. One of those bolts holds an airbag sensor so I used EXTREME CAUTION when removing this bolt. I re-mounted the airbag sensor bracket once the amp had been removed. I remove about 6" of factory harness looming on the 2 plugs to expose enough wire to easily identify the colors, and had enough room to make my connections.
I got myself a number sticker book (Home Depot). One pair at a time, I labeled each wire set (+ and -) in the factory harness using the color chart above. Where there are multiple pairs with the same number, I added an a, b, or a c after the number and wrote down what each letter represents. After I identified all the pairs needed for the new amp, it was time to start making connections. I could have cut the plugs off if I wanted to, but I opted for using a "tap connector" so I could leave the harness in tact. When I sell the car, I can put the factory system back in easily. You can get these tap connectors pretty cheap on Amazon.
I separated wires 1-4 from the harness I installed, those became the low level inputs to my new amp. Locating the low level input wires from the color chart above, I paid close attention to the + and - designations. Getting even 1 of those wrong can affect the entire system. Bose uses low level inputs for the factory amp with regular single conductor wires, so there's no need for a high to low signal converter. I made (8) connections on the factory harness side to achieve (4) channels of low level inputs for my new amp. On the other end of wires 1-4, I installed a speaker wire to RCA adaptor on each wire (also on Amazon, 1 per speaker wire), once again paying close attention to the polarity. I ended up with (4) RCA plugs that I eventually connected to my amps low level inputs.
That was the easy part, now for the speaker connections. This is where impedance comes into play and you need to "outsmart" the new amplifier. Most modern amps are stable anywhere from 2-8 ohms. From the new harness, wires 5-8 will carry the sound signal from the new amp to the existing speaker wires in my Armada. They all ended up where the removed Bose amp was and are in the existing (2) harnesses. I replaced all the factory speakers with 4 ohm speakers for the sake of easy math. The remainder of this post assumes that all installed speakers (except for the factory subwoofers) have an impedance of 4 ohms. There are (3) speakers that piggy back off of their respective master channel, the center dash speaker, and the 2 rear ceiling speakers. Therefore, I couldn’t just wire the entire channel in parallel, because it will drop the impedance below 2 ohms, but there is a work around.
Let's start with the center dash speaker. This was the most complicated part of the install. I located the wire pairs in the factory harness for the RF tweeter, RF door, and front center channel. I did a series / parallel connection for these three that will work off of the right front RCA input. The tweeter and door mid will wire parallel, while the center will be in series with those. The tweeter and mid wired in parallel gave me an impedance of 2 ohms, but when I wired those in series with a 4 ohm center channel, it brought my impedance up to 6 ohms. Most car amps can handle 6 ohms no problem. To do that, I connected the positive leads for the tweeter and mid together and connect that to the positive lead of wire #6 in my new harness. I connected the negative leads from the tweeter and mid together, and then connected that to the positive lead of the center channel in the factory harness. I connected the negative lead of the center channel to the negative lead of wire #5 in my harness, resulting in series / parallel circuit with an impedance of 6 ohms.
The problem with this is that now the left front channel (LF) had an impedance of 2 ohms (tweeter and mid only) while the RF had an impedance of 6 ohms. This means that the LF channel would be louder as the amp doesn't have to work as hard with lower resistance and will output more watts to the LF channel. The fix was to add a 4 ohm resister to the LF channel wired in just like I did for the center channel to get to 6 ohms resulting in properly balanced sound in left and right channels. I essentially fooled the amp into thinking that there are 3 speakers wired series / parallel on both the RF and LF channels. The resistor could be installed wherever, as long it is wired in series on the negative side of wire number 5 of my new harness. I got my resistor on Ebay, searching "4 ohm xxx watt resistor". I got a 200 watt resistor, but it should be sizes based on what the amp puts out in watts with a 6 ohm load. In most cases, a 100 watt resistor would be fine.
In my case, after doing the above steps all I could hear from the front channels was the center speaker as it dominated the door and dash speakers. Bose dials that speaker down in the factory amp to avoid this, so when I connected a new amp I lost that attenuation. I fixed this using an L-pad on the center speaker. You can learn all about L-pads here L Pad Calculator + Speaker Attenuation Guide
I won’t go into the explanation of them in this post, there’s too much to cover. I could have built my own L-pad using a network of resistors, but I ordered a 4 ohm adjustable L-Pad from Willy’s Hi Fi in the UK so I could fine tune the center channel volume to my liking. I needed to take into account the resistance of the L-pad and add another resistor to the left front channel so I could stay balanced. I figured out the size of the resistor I needed by connecting the L-pad into the system and checked the total connected resistance of the channel before connecting the leads to the amp. The difference in the measurements between the right and left channels was representative of the size of resistor that I needed to add. My readings were anywhere between 1.7 through 8 ohms. Once all the speakers were connected, I will picked up a few more resistance points from the wiring and components in the system (resulting in impedance), so 1.7 ohms of resistance got me to 2 ohms of impedance, therefore my amp was stable.
Yes, the center channel will now not emit both left and right stereo channels, but aside from having an amp that decodes a 5.1 or 7.1 signal, this was my only option. (that or completely disconnect the center speaker) All I wanted to use the center speaker for was to “fill in the gap” between the door speakers and dash speakers by bringing the sound closer to my driving position. The center channel is also critical for producing the crisp highs that make our music “pop” as door speakers can be muffled by passengers legs blocking the sound waves.
Moving on to the rear door and ceiling speakers. The factory Bose rear door speakers are two speakers in each door, (1) 6 ½” woofer and (1) 1” tweeter. I upgraded these as the Bose speakers were lacking the crisp highs that I like, and the vocals sounded like the person singing was doing so into a shoebox. Some component combo systems use a passive crossover to feed the woofer and tweeter, and give the pair a 4 ohm rating. Some do not and use inline capacitors for each speaker for frequency cut off, and each component (woofer and tweeter) are rated at 4 ohms each. I needed to be sure that the woofer and tweeter combo ended up with 4 ohms or greater because I would be adding in the respective roof speaker to the speaker circuit in parallel. If my door woofer and tweeter were each rated at 8 ohms, I could wire them in parallel to get to 4 ohms. If they are each 4 ohms, I would need to wire them in series (positive lead from amp to positive terminal on woofer, from the negative terminal on the woofer to the positive terminal on the tweeter, then from the negative terminal on the tweeter to the negative terminal on the amp) and end up with an impedance of 8 ohms. If my component pairs had a 4 ohm TOTAL rating, I would just need to wire them per the instructions included with the speakers, landing at 4 ohms.
I tackled the left rear side first. I located wire #7 in my new harness, and the LR door and LR ceiling factory wires in the existing harnesses. I connected the positive wire from wire #7, positive wire from the LR door and LR ceiling together. (I prefer butt splices and heat shrink tube) I did the same thing for all the negative wires. I connected the other end of wire #7 to the LR output channel of my amplifier. Depending on how I wired the doors this speaker circuit will either have a total impedance of 2 ohms (door wired in parallel or to new speaker instructions) OR an impedance of 2.7 ohms using the formula above for parallel speakers with different impedance if the door has a resistance of 8 ohms total. Bose uses a single amplifier output for the rear ceiling speakers (so they aren’t stereo), but I couldn’t add both rear ceiling speakers into the circuit I had just wired because it would have dropped the impedance below 2 ohms if I did. So I followed suit for the RR door like I did for the LR, and wired the RR ceiling speaker to the RR door channel. I did this by disconnecting the factory wires from the RR ceiling speaker and installing a new speaker wire from the RR ceiling speaker location to the area where the old Bose amp was. I already had the side panel of the cargo area removed, and the plastic ceiling speaker cover off, so I needed to fish a wire coat hanger from the RR ceiling speaker location down the side pillar to the side cover location, attach the new wire to it, and then pulled the new wire up to the speaker. I connected that new speaker wire the RR door wiring just like I did with the LR ceiling speaker. This gave me the same impedance on both rear channels and my sound was then balanced.
At that point, everything was connected (11 speakers total), and had balanced impedance for both the front and rear channels. (It’s ok if the front channels impedance does not match the rear channels impedance, as long as you are using a 4 or 5 channel amp) Most modern amps also have level adjustments for the front and rear channels, and since my impedance levels were different between the front and rear channels, I used these adjustments to “up” the output of the amp for the channels that had higher impedance, and to “down” the output of those channels with less resistance until all 4 channels were balanced to my liking.
Last but not least I needed to wire in the subwoofer. I would highly recommend a 5 channel amp for this scenario, and the following steps are for that application. The factory sub (subs) are 2 ohms each, so wiring it into one of the 2 rear channels will drop the impedance too low. With a 5 channel amp, I could use an RCA splitter and piggyback one of the rear channel low level inputs to add a 5th channel for the sub. The impedance levels will not be effected by doing this. Once I had the input side complete, I removed the driver side cargo area side panel to expose the subwoofer. I unplugged the wiring from it and removeed the 4 mounting bolts, allowing me to remove the subwoofer enclosure. There are (2) 5 ¼’ drivers in the enclosure, one on each side. I then removed the drivers to expose the factory wiring. That wire is 16 gauge and to small since I was upgrading my amp. I replaced the wiring with 14 gauge, though 12 would be ideal. I reused the the factory plug from each driver by cutting it right above the connector leaving enough wire to crimp a butt splice connector to it, and then connected a new speaker wire to them. The drivers are 2 ohms each. I wanted to add another sub but if I wired them in parallel I would have had an impedance of 1 ohm. I added a 10” sub enclosure with a 4 ohm rating, and wired that in series with the factory subs. Since I wired the factory sub drivers in parallel for a total impedance of 1 ohm, my total impedance for channel 5 of my amp ended up at 5 ohms. To do this, I connected channel 5’s positive output wire to the positive lead of the factory sub enclosure, connected the negative terminal of the factory sub to the positive terminal of the added sub, and connected the negative terminal of the new sub to channel 5’s negative output terminal. Like with the front channels, this is also a series / parallel speaker circuit.
Then BEFORE I put the panels and speaker grilles back in, I powered everything up and tested everything. I adjusted the input levels on the new amp to balance the channels to my liking, dressed my wiring, and started putting everything back together. Since I used speaker wire for the low level inputs, (RCA cables are shielded, speaker wire isn’t ) I ended up with some pretty significant engine whine coming from my new speakers. To fix this, I installed noise filters on the low level inputs right before they connected to the amp and it solved the problem completely. This is what I used: https://www.amazon.com/dp/B001EAWRZG?psc=1&ref=ppx_yo2ov_dt_b_product_details
I installed the adjustable L-pad for the center channel in the panel below the steering wheel so I could access it while driving to make adjustments. I also used an amp with a remote subwoofer control dial, and mounting that next to the L-pad dial. Music is recorded based on the producer or artists equalizer parameters, so no two albums will have an equal representation of audio frequencies. Therefore, I wanted to have as much control of that as I could right at my fingertips. I think I only spent about $1000 for everything discussed in this post, and if I had the work professionally done, it probably would have been $3k. DIY is definitely the way to go if you’re budget conscious like I am.
Hopefully this helps……