installing subs to the factory radio (line output converter help?)

[zachsmthsn]

ok, i've searched the forums, and i'm sure it's in here, but i'm still completely confused. i'm trying to install my amp and subs myself, and the only place that i'm stumped on is installing the line output converter. i have a '98 explorer - eddie bauer edition. it has a factory sub, and i would think the speaker cable that run to the sub would be enough to run to the amp, but i don't know, and couldn't find it. if anyone knows exactly what those wires are, that'd be great. also, easiest way to connect the LOC to the speaker wires in the back of the head in case i can't use the sub wires? because, i'm pretty sure that's going to be the most difficult thing about this project.

 

[toypaseo]

I connected mine right after the OEM speaker amp.

I was not sure if the signal before the amp would be enough. I had to remove the back panel for installation of the OEM exclosure, so that is where I tapped the signal.

http://s24.photobucket.com/albums/c4/toypaseo/explorer sub/106_0689.jpg

 

[zachsmthsn]

so the wires to the sub is good enough to do what i want? guess so. also, are you running two amps then, pretty much?

 

[toypaseo]

I would think so, but since I tapped the speaker leads, I cannot say for sure. I had no OEM sub amp to tap.

I just added a single Alpine amp.

At higher volumes, my bass level goes down due to the headunit cutting bass. Since you could tap the sub lead, I wonder if that would solve that problem...?

 

[zachsmthsn]

i am always scared, though, to connect wires that i don't know exactly what they go to. anyone know what all the wires to the OEM are? and also the wires after the amp.

**New Info on Installation, help needed**

Ok, so i was working on it again today, and i am pretty sure i found everything i needed to hook it up, but i don't really know.
I have everything hooked up, all the circuits completed except for one thing... the speaker wires (from the sub output from the radio) to the LOC (which is connected to the amp.) my problem is this. when i hook up what i am pretty sure to be correct to the LOC, i get nothing. but i have gotten it to work with skipping the LOC. by that i mean, touching the speaker wires straight to the rca's. what it appears to be is either the LOC isn't working, i don't have enough power to be converted to preamp level, or i'm already at preamp level. which i don't think is right, because it's not coming out of a aftermarket stereo.

my question now becomes... should i reconnect the wires to the OEM amp and then try to connect what comes out of the OEM amp to the LOC? (like toypaseo did) or is there something that should be really easy.

 

[scucci]

The mach head unit you have uses a differential output signal from the sub woofer preamp to the sub woofer amp. There are two signal wires - positive output and negative output and a shield wire. It is not RCA preamp level. Soundgate sells a 2 channel LOCB.2 that converts the differential signals to standard RCA 2 Volt peak to peak preamp level. You only need to use 1 of the channels, although you can wire them in parallel and use both. Hooking up a standard LOC can destroy the head unit sub woofer preamp by shorting one of the differential outputs to ground. The non-standard sub amp turn on from the mach head unit is a 5 volt signal. It is called the "mute" signal" on the schematic. To use this and keep the ability to mute the sub woofer you need to convert to 12 volts for your aftermarket amp turn on signal. Peripheral electronics makes a converter - LVT2 -that can be found on line for about 5 bucks or so. Using the mute signal for amp turn on helps eliminate turn on pop.

The wires from the 8 pin sub woofer connector that connect to the back of the head unit are:

Pin 1: Red/Black -sub woofer plus signal
Pin 2: Brown/Orange -sub woofer minus signal
Pin 3: Audio shield - usually black taped wire
Pin 4: Dark Green/Violet - Audio mute (5 volt amp turn on)

The audio shield should be connected only at the head unit. The shield covers the two signal wires but does not connect to anything at the amp or loc end, to prevent a ground loop.

The reason a differential output is used is for noise rejection. The positive output goes positive with respect to ground, the negative output goes negative with respect to ground. Any noise signal cutting across both lines is effectively canceled out, leaving just pure music signal. This system is also used for XLR microphones and most pro audio equipment.

Hope this helps,
Scucci

 

[zachsmthsn]

The mach head unit you have uses a differential output signal from the sub woofer preamp to the sub woofer amp. There are two signal wires - positive output and negative output and a shield wire. It is not RCA preamp level. Soundgate sells a 2 channel LOCB.2 that converts the differential signals to standard RCA 2 Volt peak to peak preamp level. You only need to use 1 of the channels, although you can wire them in parallel and use both. Hooking up a standard LOC can destroy the head unit sub woofer preamp by shorting one of the differential outputs to ground. The non-standard sub amp turn on from the mach head unit is a 5 volt signal. It is called the "mute" signal" on the schematic. To use this and keep the ability to mute the sub woofer you need to convert to 12 volts for your aftermarket amp turn on signal. Peripheral electronics makes a converter - LVT2 -that can be found on line for about 5 bucks or so. Using the mute signal for amp turn on helps eliminate turn on pop.

The wires from the 8 pin sub woofer connector that connect to the back of the head unit are:

Pin 1: Red/Black -sub woofer plus signal
Pin 2: Brown/Orange -sub woofer minus signal
Pin 3: Audio shield - usually black taped wire
Pin 4: Dark Green/Violet - Audio mute (5 volt amp turn on)

The audio shield should be connected only at the head unit. The shield covers the two signal wires but does not connect to anything at the amp or loc end, to prevent a ground loop.

The reason a differential output is used is for noise rejection. The positive output goes positive with respect to ground, the negative output goes negative with respect to ground. Any noise signal cutting across both lines is effectively canceled out, leaving just pure music signal. This system is also used for XLR microphones and most pro audio equipment.

Hope this helps,
Scucci

for the most part that makes sense, basically what i got out of that is that i can't do it the conventional way using the sub wires. correct? and you mentioned two things, the locb.2, and also the lvt2. are these things that i have to have both of? or are they things that work that i can use either one of? second question.. would it be easier/better to just do it the regular way and splice a speaker wire? even though i have everything already set up for using the sub wire.

not trying to ask too much, but could you try to say what all i still need to do to get this to work.

(if only i would've not been cheap and just bought a new radio...)

edit:
the locb.2 is $90. wow.. is there any cheaper way to do this? i can just about pay for installation for this price..

and i see what the lvt2 is, it is going to plug into the rem if i understood it correctly.

 

[DMacLennan14]

just use the speaker wires behind the head unit. you are making way to much work for yourself trying to do it other ways. i have installed tons of subs with oem head units and have never even thought about using anything but speaker wires behind the head unit.

 

[zachsmthsn]

just use the speaker wires behind the head unit. you are making way to much work for yourself trying to do it other ways. i have installed tons of subs with oem head units and have never even thought about using anything but speaker wires behind the head unit.

yeh, i think i'm going to have to end up doing that, but i still have not understood it, which makes me want to do the sub output... will splicing make me lose one of my speakers? i don't understand that..

 

[oplitic]

yeh, i think i'm going to have to end up doing that, but i still have not understood it, which makes me want to do the sub output... will splicing make me lose one of my speakers? i don't understand that..

you won't lose anythng. it's only taking the signal and converting it into rca level. Just take the LOC and tap into the wires behind the head unit then run the rca's to the back like you normally would. There's no reason to go any where else. Also, if you ever decide to put in an aftermarket deck later on, the rca's are already there, no need to re-route them. And it's not hard to route them anyways, so just do it the first time.

 

[zachsmthsn]

but that doesn't make any sense to me, i'm sorry i'm being kinda difficult here, but i mean.. when there are 8 wires coming out of the back, they are all going to something. if i cut and then splice 4 of those wires, wouldn't i lose the speakers that those wires are connected to? because, then instead of those wires going to the speakers, they're going to my amp.
am i overthinking this, am i actually losing something, am i thinking of it wrong, or am i jsut stupid...

 

[DMacLennan14]

you arent cutting the wires. you are adding to the wires. just strip some of the jacket off of the wire and tie the loc wire to that. at the end, you will have wires that are now in the shape of a "Y". one end going to the radio, one to the speaker, and one to the loc. i hope that makes sense, if not, i can show a picture.

 

[zachsmthsn]

you arent cutting the wires. you are adding to the wires. just strip some of the jacket off of the wire and tie the loc wire to that. at the end, you will have wires that are now in the shape of a "Y". one end going to the radio, one to the speaker, and one to the loc. i hope that makes sense, if not, i can show a picture.

so you aren't splicing them by definition, or maybe i'm confused on the definition.. lol
but thanks for your help, because until now, i've been pretty much stupid.

and you just kinda tie them on there? or should i tape them on there? solder.. what's the best attachment approach?

 

[91exploreron37]

You can tie them on there and tape them(thats what I did in my old car) but for a more appropriate connection soldering is always best.

 

[DMacLennan14]

so you aren't splicing them by definition, or maybe i'm confused on the definition.. lol
but thanks for your help, because until now, i've been pretty much stupid.

and you just kinda tie them on there? or should i tape them on there? solder.. what's the best attachment approach?

i used the term "tie" loosely. your best connection is going to be with solder. i only use solder if it is a 24 gauge wire or smaller. i install remote starts and stereos for a living and have never had one come back for a wire falling off, so i find no need to solder every connection as long as the wire is tight enough and taped.

 

[zachsmthsn]

thanks to everyone for the help on this. i couldn't have done it without y'all. i am definitely a noob to this, and although i did every other thing without help, this was definitely a major roadblock.

i'm going to do this either in a few minutes or tomorrow, but i'll post about the success or fail of this.

UPDATE:
this is pissing me off quite a bit. i stripped about a quarter inch off the + and - of the left and right rear speakers. then i twisted/tied the corresponding wires from the LOC to them, and taped it up. then i connected the rca's to the other end of the LOC, and then to my amp. my amp definitely has power, and i've gotten thuds from my subs, so i know they are hooked up good, and yet after everything is hooked up, i have no sound from my subs! so it seems to me, though i'm probably wrong, that there's a problem with the LOC. the problem is definitely somewhere between the radio and the rca's. is there a way to test the LOC? continuity test, i guess.
but does anyone have any other suggestions of what i may have wrong?

 

[scucci]

The speaker wires coming out of the head unit do not carry the sub woofer frequencies. The Mach head unit has an internal crossover set to about 150 HZ, anything above this goes to the door speakers. You need to either get the high level to a standard LOC from the sub woofer speaker wires, or use the differential converter LOCB.2 from soundgate connected to the 8 pin sub woofer connector. I do not know if any other companies make one. The low voltage trigger is only needed if you want to use the mute/turn on wire from the head unit to power the aftermarket amp. If you just use a switched 12V source you do not need the LVT2.
http://www.soundgate.com/index.php?request=product.details&productid=431&usereferrer=1&
http://www.soundgate.com/index.php?...ls&categoryid=25&productid=365&usereferrer=1&

I don't work for soungate. I just use the setup I have described in my Expy.

Good Luck
Scucci

 

[zachsmthsn]

but how can that be the only way to do it? because i know of at leas two other people who have done it without that. i don't understand it. gah.. this stuff is frustrating..

 

[91exploreron37]

Which LOC are you using? The schosche?

 

[zachsmthsn]

FINALLY! THEY ARE WORKING, AND I AM SO RELIEVED.

the LOC i was using isn't scoche, i could go look at it, but that's not needed anymore. i think there was something wrong with the LOC i had. i went to soundsgreat and they let me use another one. i hooked it all up the same way as before, and was testing it out. i got sound out. finally... but it was barely anything. with the bass all the way up and sound and amp settings good. so i was a bit pissed off... but then the soundsgreat guy told me to try something else, hooking rca's directly to the sub wires before the amp. so i did that, and FINALLY it's working. so the answer to all this difficulty and every complicated thing was simply this.. skip the LOC. so i hope this thread stays around as a testament to all the newbies who don't know anything and then get made look stupid by the answer being easy.