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How to: Subwoofer installation

26870 Views 128 Replies 28 Participants Last post by  RednDead
Howdy. Sorry if I suck at writing tutorials. I know a subwoofer is something the majority of the owners of these cars are going to want, so I figured I’d share my knowledge a bit.
Background on me, I spent 4 years as a 12 volt electronics installer, and I’m pretty sure I still have an active MECP Advanced certification. The techniques I’m using in this guide are exactly what you’d get if you took your car to get a sub amp installed professionally.

There are some things I may or may not show in my install that I don’t advise doing because they’re not cost effective - you can get a professional sub amp install for about $120 labor, and anything that runs up the cost closer to that mark makes it less worth it to DIY.
1. Integrating with the factory amplifier by making your own T harness. This is cool, but also costs about $40 in parts just by itself. We will be using a military splice instead.
2. Wire dressing. Also very cool, but not cost effective if you’re doing a single install. The power kit I recommend has the engine compartment portion of the power wire pre-dressed, which is the only part that actually needs to be dressed.

With that said, here’s a list of stuff I used.

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@removedonut

Wanted to drop a note and thank you for the detailed writeup! Used your guide to get my Basspro Hub installed. Everything went smooth.

View attachment 18761

View attachment 18762
Glad to hear. Clean install.
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I already have the basspro hub from my previous vehice, so my question is, what differences would i have to do in terms of wiring?
Can i still hook everything up as you mentioned in your guide?
I already have the basspro hub from my previous vehice, so my question is, what differences would i have to do in terms of wiring?
Can i still hook everything up as you mentioned in your guide?
Yes.
I have possibly solved the weird amount of bass coming from my sub. I turned off the bass restorer. It was adding in weird boosts of various frequencies. Only time will tell.

Steve
I have possibly solved the weird amount of bass coming from my sub. I turned off the bass restorer. It was adding in weird boosts of various frequencies. Only time will tell.

Steve
I just installed mine yesterday and I noticed this issue as well. Was about to go in today and rip it out and use a regular LOC. maybe I’ll mess with it a little more today and try your method.
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I just installed mine yesterday and I noticed this issue as well. Was about to go in today and rip it out and use a regular LOC. maybe I’ll mess with it a little more today and try your method.
I changed my input to using a LOC and had to drop its sensitivity. I added comments in this thread somewhere

Steve
Great write up. One question, you don't need speed wire if you are going the cutting ends off the RCA cables?
Great write up. One question, you don't need speed wire if you are going the cutting ends off the RCA cables?
Correct.
My wiring kit showed up today. I opened my amp and noticed it had some 'Speaker Wire Cable to Audio Male RCA Connector Adapters' included. Would you use them, or just chop the ends off an RCA? I don't have speed wire I'd have to pick it up.

Also did you make an amp rack yourself? I have never done it and I am just mounting one amplifier which is about 9 by 7.5 inches.
My wiring kit showed up today. I opened my amp and noticed it had some 'Speaker Wire Cable to Audio Male RCA Connector Adapters' included. Would you use them, or just chop the ends off an RCA? I don't have speed wire I'd have to pick it up.

Also did you make an amp rack yourself? I have never done it and I am just mounting one amplifier which is about 9 by 7.5 inches.
Use Em.
My amp is held in place by the power wire which comes under the spare tire cover and a piece of 2 sided velcro.
My wiring kit showed up today. I opened my amp and noticed it had some 'Speaker Wire Cable to Audio Male RCA Connector Adapters' included. Would you use them, or just chop the ends off an RCA? I don't have speed wire I'd have to pick it up.

Also did you make an amp rack yourself? I have never done it and I am just mounting one amplifier which is about 9 by 7.5 inches.
Yeah use those.

My amp rack is a sheet of ABS i found by the dumpster. Plastic cutting boards actually work great for amp racks though, a lot of audio shops will just spray paint those black and send it.
Where did you guys mount your fuse holder? I had mine loose on my old car, but I am trying to do everything the right way this time. I have seen people fabricate mounting brackets but that seems like a lot work.
After a lot of planning and purchasing tools I wired everything up and THE BIG MOMENT, WOOO!!! Nothing... solid protect light.

I check all my wires and signal wires to make sure everything is secure. Still solid protect light. A trip to home depot to buy a multimeter all of my voltages are good on remote and power. I can only think of the amp being at fault so I am getting it replaced (thanks Amazon). Hopefully it will be here tomorrow. I just want to have this project done so I can put my car back together and enjoy the music😅

I can only imagine how many more struggles there would have been if I didn't have this guide as a reference, thanks again. At least with all my struggles I picked up some new skills along the way.

Crossing my fingers that I connect everything to the new amp and we are good.

Ricky
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After a lot of planning and purchasing tools I wired everything up and THE BIG MOMENT, WOOO!!! Nothing... solid protect light.

I check all my wires and signal wires to make sure everything is secure. Still solid protect light. A trip to home depot to buy a multimeter all of my voltages are good on remote and power. I can only think of the amp being at fault so I am getting it replaced (thanks Amazon). Hopefully it will be here tomorrow. I just want to have this project done so I can put my car back together and enjoy the music😅

I can only imagine how many more struggles there would have been if I didn't have this guide as a reference, thanks again. At least with all my struggles I picked up some new skills along the way.

Crossing my fingers that I connect everything to the new amp and we are good.

Ricky
What’s your gain set to? Some come out of the box set to the maximum which will frequently trip the protect circuit.

If you continue to have issues, make sure you’re metering your voltages with your ground probe on the amp’s ground terminal and not some other point too. You’ll be able to see a ground issue manifest as a reduced voltage that way.
What’s your gain set to? Some come out of the box set to the maximum which will frequently trip the protect circuit.
I turned it all the way down to be sure. It was such a disappointment since I was so excited to hear the subwoofer and instead spent a few hours troubleshooting lol.

I will have to follow up once I receive the new amp.

Ricky
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Wow, the new amp works. At least I can send the bad one back.

Going to take the car for a drive and then set the gain in the morning.

Ricky
I have a 22 premium and I tapped the RCAs into the one speaker it said In the write up and I'm getting the engine noise in the subs even after I unplugged the module by the glove box. Any way to get rid of this.

Also I tapped into the green wire for the shit off and it doesn't.

Fun times.
I have a 22 premium and I tapped the RCAs into the one speaker it said In the write up and I'm getting the engine noise in the subs even after I unplugged the module by the glove box. Any way to get rid of this.

Also I tapped into the green wire for the shit off and it doesn't.

Fun times.
Accessory circuits in this car don’t turn off until the car is locked and the keys aren’t nearby.

If you’re getting induced noise in your subwoofer something has gone tremendously wrong. A bad ground can cause this, among other things, but i’m probably gonna need more info to troubleshoot this.
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bad ground and or loose/damaged wire either ground or rca would be a good start
2
Tapping input signal (GR86 premium/BRZ limited):

If you’re using the speed wire I recommended, slice it open and pull out the appropriate length of 2 wire pairs. White and gray are the standard colors for FL/FR so i’ll be using those sets.

We’ll be accessing everything at the factory amplifier. There is a foam piece that is in the way held in by 3 visible push pins. Pop those up with your pry tool and flip the foam piece out of the way so you can access the wiring harness. Unplug the harnesses, and using your razor blade cut back the factory wire dressing a few inches.
View attachment 6330
There are 2 options for getting signal back here: high level or low level. If you’re not sure, use low level. High level will generally require you to solder your speaker wires to the high level input harness, and most people reading this probably don’t own a soldering iron. If you’re using low level, you can simply cut one end off your RCA cables, strip back the insulation, and splice the wires directly into the low level inputs at the factory amplifier. It will generally be fairly obvious what color wire inside the RCA is positive/negative. Alternatively, you can buy 2 female RCA pigtails on amazon for fairly cheap and just splice those in.
Amp turn-on is also found here, it is the dark green wire in the middle of the harness. You can splice the 18ga blue wire in your power kit into there.

Here are pins and wire colors:

Low level:
FL (+/-): ltgrn pin A3/yellow pin A9
FR (+/-): white pin A4/ltblu pin A10

High level:
FL (+/-): ltgrn pin A1/blue pin A5
FR (+/-): brown pin A2/purple pin A6

Pins are counted right to left.
The positives are all on the top row directly above their corresponding negative wire so verifying pins is easy.


When making your connections, use a military splice. This is the technique every (good) professional installer uses. I highly advise against using T-taps or any other hackjob wiring connector.

Start by stripping back a small section of insulation.
View attachment 6331
Use your hook tool to poke a hole through the center of the strands.
View attachment 6332
Strip the end off the wire you’re splicing in, and twist the strands so they stay together nicely.
View attachment 6333
Wire go in hole.
View attachment 6334
Wrap the wire around, then pinch the connection point to close the hole you poked.
View attachment 6335
Apply electrical tape. Less is more here, you don’t need more than about a centimeter of tape.
View attachment 6336
Once you’ve made all your connections, reapply factory wire dressing. Subaru just uses electrical tape, so this is easy.
View attachment 6337
Really appreciate this entire tutorial and you have inspired me to attempt my own install. I was hoping I could ask a question to clarify something regarding the amp remote wire.

Just wanted to confirm, is this highlighted green wire the one I should be using for remote?
Gesture Electrical wiring Wrist Cable Electrical supply


Part of why I am asking is because I am having an issue with my amp going into protect mode immediately upon starting up and music playing. I thought I could make things "easier" for myself by purchasing the ebay connector/harness that was listed in a YouTube video mentioned above. I am starting to think maybe the connector is part of my issue.
Looking more closely at the ebay connector, I found that the remote wire they have provided is actually connected to what appears to be A3, instead of the actual remote wire. Below is a picture of the ebay connector. The colors do not match up with the factory cables by the way, but the blue cable highlighted here is what they gave me for the remote wire. This looks like it is connected to A3.​
Electronic component Electronic engineering Networking cables Electrical wiring Cable


As of right now, my amp is only connected to power, ground, and remote wires. When I turn my car on, the amp immediately goes into protect mode. I was wondering if this may be part of the issue. I also found that if I turned my volume all the way down, the amp goes out of protect mode and into regular mode. As soon as I turn the volume back up to ~5, the amp goes back into protect mode. It seems like the protect mode light almost pulses with the music, which also leads me to think maybe this ebay connector is my issue.

I installed this yesterday and ended up spending about 8 hours trying to figure it out. Another 4 hours this morning and I feel like I am losing my mind. I have quadruple checked my power and ground wires for proper connections, I have used a voltage meter to make sure I was getting power to the amp. I have tried alternate ground locations (currently using your suggested location). I am at a loss. I have tried connecting the subwoofer and the same thing happens. I figured my issue had to be with power, ground, or remote, due to the amp going into protect mode before the sub is even connected. My power and ground seem good which is why I am now questioning the ebay connector.

EDIT: Had a bit of an "F IT" moment and decided to just make my own remote wire using the green you mentioned instead of using the one that came with the ebay harness. Wow, that was my issue the entire time. Amp started up no problem. No protection mode. I connected my sub and it immediately started working. I should have just done it all manually instead of buying the ebay harness.
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