How to install sub into factory head unit

Cereal13 · 02-03-2007, 12:19 PM

hi i am new to the sit and just got an STI i am trying to put my subwoofer into it from my old one. I was wondering how to tie it into the stock head unit??

johnlude85 · 02-03-2007, 12:23 PM

i think you just tap into the rear speakers to get power to the sub. then just install the amp as usual (to the battery, remote wire to a 12 volt source)

Cereal13 · 02-03-2007, 12:26 PM

what about the rca cables do i not use them...i have found the wiring diagram for the 05 stis but i wasnt sure if i needed the rca cables

SubieGsR · 02-04-2007, 12:59 AM

bump, i would like to know also.

rekedevoate · 02-04-2007, 03:36 AM

what you need is a line out converter. what it does is it tapes into a regu. ab channel, and convertes to a d channel by just making it a line out thats not pre-amped. your mids run off a ab channel, and a sub needs a d channel. your ab channel is pre-amped from the deck, and a d channel(from a aftermarket deck) is not. thats why its in the back of most aftermarket deck's in order to hook up rca's to utilize and incorprate a aftermarket sub. they usualy run about 8 to 20 bucks, depends how much you want to spend. ebay is a good place to get one. and just follow the instructions to install it. its very ez. hope this helps you man. if you need more help, just pm me.

metoo · 02-08-2007, 05:27 PM

Cereal13,

Just in case you (or someone even less knowledgeable about car audio) didn't understood that last post, so I'll I explain it in anti-cliff note mode.

Most factory head units only have a single harness connection in the back. This harness provides power to the head unit and signal output to the speakers. The speaker outputs are called "speaker-level" or "high-level" output. Pre-amp out puts are called "low-level." This is where RCA cables are used, but pre-amp outputs are not on most factoru head units.

The head unit has its own amplifier, but as most of us know, it is not powerful enough to get the sound and feel we desire from a subwoofer. Therefore we need an external amplifier. Amps can have both high-level and low-level input. If it has high-level input you can simply connect a wire to rear speaker wires and run them to the amplifier. If you the amp only has low-level inputs, then you will need a high-level/low-level converter, similar to the one pictured HERE.

There is a definate down side to this sort of installation. For one, you are converting high to low, which isn't the best for sound quality, but since most people will do this just for bass, it's not big deal. The other thing is that your subwoofer volume and sound will be directly effected by your tone, balance, and fade setting on the head unit.

nasti05 · 02-22-2007, 05:18 PM

scosche is horrible

02-03-2007, 12:19 PM	#1
Cereal13 Amateur STI Driver Car: silvr WX STi Fav Mod: Cobb Accesport Location: Richmond VA Posts: 9 Join Date: Feb 2007 Trader Rating: (0)	How to install sub into factory head unit hi i am new to the sit and just got an STI i am trying to put my subwoofer into it from my old one. I was wondering how to tie it into the stock head unit?? This ad is not endorsed by this member. Please register or login to hide this ad.

02-22-2007, 05:18 PM	#7
nasti05 Junior STI Driver Car: 05 WRX STi (wrb/gold Fav Mod: Utec Location: Gainesville,FL Posts: 97 Join Date: Jul 2006 Trader Rating: (0)	scosche is horrible This ad is not endorsed by this member. Please register or login to hide this ad.

02-03-2007, 12:23 PM	#2
johnlude85 Spec C Club Car: 2005 OBP STi Fav Mod: CBE Location: Milford, NJ/Allentown, PA Posts: 1,072 Join Date: Aug 2006 Trader Rating: (0)	i think you just tap into the rear speakers to get power to the sub. then just install the amp as usual (to the battery, remote wire to a 12 volt source)

02-03-2007, 12:26 PM	#3
Cereal13 Amateur STI Driver Car: silvr WX STi Fav Mod: Cobb Accesport Location: Richmond VA Posts: 9 Join Date: Feb 2007 Trader Rating: (0)	what about the rca cables do i not use them...i have found the wiring diagram for the 05 stis but i wasnt sure if i needed the rca cables

02-04-2007, 12:59 AM	#4
SubieGsR Junior STI Driver Car: '07 Sti Limited Fav Mod: oem short shifter Location: Bellevue, WA Posts: 171 Join Date: Dec 2006 Trader Rating: (1)	bump, i would like to know also.

02-04-2007, 03:36 AM	#5
rekedevoate Professional STI Racer Car: 2006 Siliver STi Fav Mod: Recaro's Location: HD Germany Posts: 610 Join Date: Jul 2006 Trader Rating: (0)	what you need is a line out converter. what it does is it tapes into a regu. ab channel, and convertes to a d channel by just making it a line out thats not pre-amped. your mids run off a ab channel, and a sub needs a d channel. your ab channel is pre-amped from the deck, and a d channel(from a aftermarket deck) is not. thats why its in the back of most aftermarket deck's in order to hook up rca's to utilize and incorprate a aftermarket sub. they usualy run about 8 to 20 bucks, depends how much you want to spend. ebay is a good place to get one. and just follow the instructions to install it. its very ez. hope this helps you man. if you need more help, just pm me.

02-08-2007, 05:27 PM	#6
metoo Junior STI Driver Car: 04 STi Posts: 76 Join Date: Nov 2005 Trader Rating: (0)	Cereal13, Just in case you (or someone even less knowledgeable about car audio) didn't understood that last post, so I'll I explain it in anti-cliff note mode. Most factory head units only have a single harness connection in the back. This harness provides power to the head unit and signal output to the speakers. The speaker outputs are called "speaker-level" or "high-level" output. Pre-amp out puts are called "low-level." This is where RCA cables are used, but pre-amp outputs are not on most factoru head units. The head unit has its own amplifier, but as most of us know, it is not powerful enough to get the sound and feel we desire from a subwoofer. Therefore we need an external amplifier. Amps can have both high-level and low-level input. If it has high-level input you can simply connect a wire to rear speaker wires and run them to the amplifier. If you the amp only has low-level inputs, then you will need a high-level/low-level converter, similar to the one pictured HERE. There is a definate down side to this sort of installation. For one, you are converting high to low, which isn't the best for sound quality, but since most people will do this just for bass, it's not big deal. The other thing is that your subwoofer volume and sound will be directly effected by your tone, balance, and fade setting on the head unit.