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How to: Subwoofer installation

26874 Views 128 Replies 28 Participants Last post by RednDead, 9 d ago

removedonut

Discussion Starter · Feb 24, 2022 (Edited)

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.

sharetext.me

Untitled 2022-02-23 20:40:58 - Share Text

Untitled 2022-02-23 20:40:58

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Reactions: 5

101 - 120 of 129 Posts

RednDead

· #101 · 14 d ago

Hey guys. Gonna bump this thread as I do have what I imagine to be a simple question. So I wired in the sub to the factory amp (brz limited) thanks to this amazing guide. I used butt splices to tap into the low end cables (cut the ends of RCA cables off). The sun now kicks nice and deep, but my sound quality is ruined. Tons of static, and the audio cuts in and out when it’s at volume 22+.

Would an aftermarket amp fix the static issue or is it due to the crimp connections I used? If amp, does anyone have a recommendation for one that will fit nicely in the trunk?

EmperorJJ1

· #102 · 14 d ago

what amp do you have for the sub? if i had to guess its a loose/bad ground on the amp power connections and possibly ground loop problem with the RCA input connections

RednDead

· #103 · 13 d ago

EmperorJJ1 said:
what amp do you have for the sub? if i had to guess its a loose/bad ground on the amp power connections and possibly ground loop problem with the RCA input connections

I am using low level connections (RCA) on the stock amp as the guide showed. Grounded to the strut bolt using 10 gauge wire from the wiring kit. The positive is ran to the battery, again 10 gauge wire from the kit.

removedonut

Discussion Starter · #104 · 13 d ago

RednDead said:
I am using low level connections (RCA) on the stock amp as the guide showed. Grounded to the strut bolt using 10 gauge wire from the wiring kit. The positive is ran to the battery, again 10 gauge wire from the kit.

Strut bolts aren’t a smart grounding location, especially if you’ve not prepared them with a wire wheel. Decent chance you’re ground looping your inputs with that.

RednDead

· #105 · 13 d ago

removedonut said:
Strut bolts aren’t a smart grounding location, especially if you’ve not prepared them with a wire wheel. Decent chance you’re ground looping your inputs with that.

Oh okay then that's probably it. Any recs on where to move the ground to? I saw someone said something about the seat bolts but idk where that is.

removedonut

Discussion Starter · #106 · 13 d ago

RednDead said:
Oh okay then that's probably it. Any recs on where to move the ground to? I saw someone said something about the seat bolts but idk where that is.

Under the rear seat bottoms. You should have needed to remove at least one of them to run your power wire.

Reactions: 2

RednDead

· #107 · 13 d ago

removedonut said:
Under the rear seat bottoms. You should have needed to remove at least one of them to run your power wire.

Thanks for your help! Your knowledge is so insanely helpful.

RednDead

· #108 · 13 d ago

Update for anyone interested: it was indeed because of the strut bolt mounting. I skipped over that in the tutorial haha

Reactions: 3

Tarman

· #109 · 12 d ago

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

What speakers are amplified above? Just the front 6 or the doors only? How are the rears powered?

removedonut

Discussion Starter · #110 · 12 d ago

Tarman said:
What speakers are amplified above? Just the front 6 or the doors only? How are the rears powered?

Just the two front door speakers. Front 3.5s, front tweeters, and rear 3.5s are all just run off deck power.

RednDead

· #111 · 12 d ago

Nvm lol still got some static. The new grounding point did get rid of I'd say about half of it but it sounds like the artists I listen to have lisps. Probably just gonna buy an amp because if it isn't the butt splices I used to connect the RCAs to the low side, idk what it is

Reactions: 1

EmperorJJ1

· #112 · 12 d ago

really your chasing a ghost and adding an amp for your highs isnt necessarily going to fix anything. Just to clarify you just added an amp for the sub correct? is the sub sounding off or just the highs? and highs are completely stock or what all have you done?

without getting answers to the above i would possibly look into a different connector. im making assumptions here but if your highs are completely stock and having sound issue then it would have to be something you did when installing the sub. my best guess would be the butt connectors are adding in resistance in the connection thus sounding bad. either something is loose or a different connector is needed (or both). a few other options would be adding in a ground loop isolator... these don't really fix the problem but a band aid stops the bleeding too so they have their place.... but they would only help whatever you have that has an aftermarket amp. stock amp need not apply. Lastly you could take a spare piece of wire if you have it and connect the ground of the aftermarket amp to the RCA connection at the aftermarket amp (outer shield and see if it sounds any better? long shot really but can sometimes fix things

i generally prefer these for certain connections.

www.amazon.com

Conext Link 300 Closed End Crimp Cap Terminal Connector 22-18 16-14 12-10GA AWG Gauge Wire （18693）: Amazon.com: Industrial & Scientific

Conext Link 300 Closed End Crimp Cap Terminal Connector 22-18 16-14 12-10GA AWG Gauge Wire （18693）: Amazon.com: Industrial & Scientific

www.amazon.com

they dont function as smoothly as a butt connector but the wires are twisted together and held but the crimp vs a butt the connection is actually made via the metal connector. who knows what metal that is, what quality it is, and what kind of resistance its adding on your electrical connection.

See less See more

RednDead

· #113 · 12 d ago

EmperorJJ1 said:
really your chasing a ghost and adding an amp for your highs isnt necessarily going to fix anything. Just to clarify you just added an amp for the sub correct? is the sub sounding off or just the highs? and highs are completely stock or what all have you done?

without getting answers to the above i would possibly look into a different connector. im making assumptions here but if your highs are completely stock and having sound issue then it would have to be something you did when installing the sub. my best guess would be the butt connectors are adding in resistance in the connection thus sounding bad. either something is loose or a different connector is needed (or both). a few other options would be adding in a ground loop isolator... these don't really fix the problem but a band aid stops the bleeding too so they have their place.... but they would only help whatever you have that has an aftermarket amp. stock amp need not apply. Lastly you could take a spare piece of wire if you have it and connect the ground of the aftermarket amp to the RCA connection at the aftermarket amp (outer shield and see if it sounds any better? long shot really but can sometimes fix things

i generally prefer these for certain connections.

Conext Link 300 Closed End Crimp Cap Terminal Connector 22-18 16-14 12-10GA AWG Gauge Wire （18693）: Amazon.com: Industrial & Scientific

Conext Link 300 Closed End Crimp Cap Terminal Connector 22-18 16-14 12-10GA AWG Gauge Wire （18693）: Amazon.com: Industrial & Scientific

www.amazon.com

they dont function as smoothly as a butt connector but the wires are twisted together and held but the crimp vs a butt the connection is actually made via the metal connector. who knows what metal that is, what quality it is, and what kind of resistance its adding on your electrical connection.

I didn't add an amp for the subwoofer. I tapped the cables into the low level RCA wiring from the factory amp (brz limited model) as the guide shows, only used butt splice connectors instead of a military splice as I don't have the tool required to poke a hole through the wire

EmperorJJ1

· #114 · 11 d ago

doing some digging it looks like you have the rockville 8in spare tire sub with built in amp

RednDead

· #115 · 11 d ago

EmperorJJ1 said:
doing some digging it looks like you have the rockville 8in spare tire sub with built in amp

Yea I do. But either way I'd have to tap into the car's stock amp wiring to have it work.

removedonut

Discussion Starter · #116 · 11 d ago

RednDead said:
Yea I do. But either way I'd have to tap into the car's stock amp wiring to have it work.

my personal experience installing rockville products biases me towards saying that the integrated amp is backfeeding dirtiness into the inputs through its cheap chinesium components. in the interest of thorough troubleshooting however, I would compare how the car speakers sound after disconnecting your sub amp power from the battery but leaving signal connected to the stock amp. If the noise goes away, it’s the rockville’s fault. if it stays, it’s likely an issue with your connections.

RednDead

· #117 · 11 d ago

removedonut said:
my personal experience installing rockville products biases me towards saying that the integrated amp is backfeeding dirtiness into the inputs through its cheap chinesium components. in the interest of thorough troubleshooting however, I would compare how the car speakers sound after disconnecting your sub amp power from the battery but leaving signal connected to the stock amp. If the noise goes away, it’s the rockville’s fault. if it stays, it’s likely an issue with your connections.

That's a great idea to test it actually. I'll do this later and report back! Thanks

Silvertoy

· #118 · 11 d ago

RednDead said:
Hey guys. Gonna bump this thread as I do have what I imagine to be a simple question. So I wired in the sub to the factory amp (brz limited) thanks to this amazing guide. I used butt splices to tap into the low end cables (cut the ends of RCA cables off). The sun now kicks nice and deep, but my sound quality is ruined. Tons of static, and the audio cuts in and out when it’s at volume 22+.

Would an aftermarket amp fix the static issue or is it due to the crimp connections I used? If amp, does anyone have a recommendation for one that will fit nicely in the trunk?

This is what happened to me as well, I'm guessing we shorted something in the head unit or telematics unit. I ended up getting an eq to tune out some of the statixmc, best I could do until a full head unit replacement comes out

RednDead

· #119 · 11 d ago

Another small question, if it is indeed the subwoofer'

Silvertoy said:
This is what happened to me as well, I'm guessing we shorted something in the head unit or telematics unit. I ended up getting an eq to tune out some of the statixmc, best I could do until a full head unit replacement comes out

Welcome to the static ship, glad to have you aboard!

Unfortunately it rained today but tomorrow if it’s clear I will hop into my BRZ to determine if it’s the subs causing the static. If it is, I’ll try switching my low side RCA splices to the high side connections, which the other guide recommended doing. I’ll let you know how my results turn out so maybe I can provide you with a fix. Cheers!

Silvertoy

· #120 · 11 d ago

RednDead said:
Another small question, if it is indeed the subwoofer'

Welcome to the static ship, glad to have you aboard!

Unfortunately it rained today but tomorrow if it’s clear I will hop into my BRZ to determine if it’s the subs causing the static. If it is, I’ll try switching my low side RCA splices to the high side connections, which the other guide recommended doing. I’ll let you know how my results turn out so maybe I can provide you with a fix. Cheers!

So at this point,
-I've replaced the door speakers, running at full range of separate amp
-Added a set of component pods that sit in my back seats, running full range off separate amp
-Added some 6x9 boxes in the trunk, running 50-200hz on separate amp
-Added bass hub in tire well on separate amp
-Added 8 channels of amplification,

I took the signal for all of this "pre-amp" before the door speaker amp in the rear, which feeds into a separate eq before the amps so I can eliminate the static from 1,5-6khz. ground wire is the "latch" bolts.

The gawdawful sound is coming from the dash speakers, so I just bumped up the gain on everything else. All that and hours of tuning and it still sounds worse than the factory Alpine in my jeep.

the bass hits harder though.

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