Question with adding a subwoofer

[SVXdc]

Originally Posted by brz408

Is the 10 pin connector the same on both sides; the back of the HU and input to the OEM amp?

Yes, they are the same physically. However, the pin assignments ("pin-outs") are very different.

I assume that direct from the back of the HU it would be a "stronger" connection in terms of signal strength and also any wiring becoming undone.

No, they would be essentially the same (the levels might be lower in the trunk by a miniscule amount, due to the signals traveling through a few extra feet of wire, but probably not noticeable). The main difference is that behind the HU you also have access to the HU's rear speaker outputs (not available at the connectors in the trunk). In the trunk you have access to the outputs from the OEM amp that go to the door speakers (not available at the HU).

Even in the trunk it sounds like I have access to all A-G. Maybe I am missing something?

No, that's correct.

In between the output from HU and input to the OEM amp is there anything that intercepts the signal?

No. See the factory wiring diagram in Spaceywilly's post -- the lines run straight from the HU to the amp ("HD2" is just a pair of interconnect harnesses). The lines also T off and go to the front speakers.

[connecting behind the HU] sounds easier to me. I just need a wiring diagram. I assume that its the same as the input connector on the OEM amp?

If you want the HU's front speaker channels, it would be the same effort tapping behind the HU or tapping at the OEM amp. Again, see diagram in Spaceywilly's post. The full diagrams were posted in another thread here.

So this Audiotek LOC requires its own power and grounding. On the back of the HU is there also a 6 pin connector that I can tap into? Or is it a different type of connector?

Both the HU and OEM amp have 10-pin and 6-pin connectors. You can get +12V Battery and ground at either location, but the pin-outs are completely different. See wiring diagrams.

So I can skip connecting these [LOC's +12V, Ground, and Remote Output]? I thought from the quote immediately above that I will need to power and ground the LOC. But then it sounds like the LOC that I have has additional features which I don't need b/c the amp already supplies that. So, I can actually skip E and F on my LOC. Correct?

Correct -- I think you can skip those connections, but I can't say for certain because I don't have any docs about this LOC, and couldn't find any site for the manufacturer.

Most LOCs are "passive" -- they don't require any power for the LOC function. But there is a small chance that yours is "active" (contains powered components for the audio circuits). The amp trigger circuit definitely requires power to work (but you don't need that feature).

I'm using an older version Alpine amp (mrv-f352) for the time being. I want to get a mono amp smaller in size down the road. So I don't think I need to connect G for the time being correct?

The MRV-F352 amp does have a terminal for "remote" trigger input. You don't need the LOC's wire G, but you do need to connect the HU's trigger output to the amp's trigger input.

Since it's a 5-channel amp, you could even use it to power your door speakers instead of the tiny OEM amp. Just be sure to start out with the Alpine amp's GAIN knob all the way down, and turn it up slowly.

If you do that, you could use a regular Toyota harness (the type normally used to install an aftermarket HU -- Metra 70-1761, Scosche TA02B, or equivalent -- should be easy to find one locally). Then you won't need to splice into any factory wires. You should re-pin it so the wire colors are in the appropriate pins for their functions (e.g., WHITE wire into 10-pin pin #3, for Left Front Positive. Re-pin the 4 GREEN and VIOLET wires into the pins for the outputs to the door speakers). [ADDED: See this thread: How to use the OEM amp Wiring]. Connect things as follows:

• Front speaker channels (coming from the HU, via the Toyota harness) to your LOC
• LOC's RCAs to the MRV-F352 amp's channel 3 & 4 inputs
• HU's amp trigger to amp's remote terminal
• Amp's channels 3 & 4 outputs to the wires going to your door speakers (via the Toyota harness)
• Configure your amp to get the sub (channel 5) "INPUT CHANNEL" from channels 3+4
• Connect your sub speaker to the amp's channel 5 output

You can use the amp's CROSSOVER knobs to free the door speakers from trying to reproduce the lowest frequencies (which may make them perform a little better).

I'm trying to go no harness at this point. I am looking to splice and use butt connectors then crimp properly. Just want to get this out of the way this weekend.

You can avert problems by not splicing into factory wires, and be able to quickly return to stock. That can be really helpful for troubleshooting, or when you sell the car.

Edit:

From Post #22:

[HU pin-out that xcelir8brz got from an older version of my Subaru pin-out on NASIOC]

I think I can connect like so from the back of the head unit:

1A
5B
2C
6D
4E
7F
G (not needed)

Correct, if you connect behind the HU (except you probably don't need E or F). But it looks like you can do everything you want in the trunk.

[MasterMech77]

Originally Posted by oldpueblo

Just a bit of info... I see the RCA wires run with the power. This is never a good idea, the reason is the magnetic flux you get off of the power wires really plays havoc with you sound signal. Even a good twisted pair of RCAs will be effected in the long run. Best thing to do is run the power on one side and the audio on the other side of the vehicle.

The other thing that could happen is say God forbid, but you have a short in the main power wire you will not have to worry about it buring a hold in to your RCAs and shorting out the inputs on your amp. A short to ground is bad too, but most amps have fuses there to protect themselves, but not in the RCA side of things.

Just something I noticed a lot of people don't think about or know when they run the wires for the Subs. That and I never like to see anything bad happen to our babies

Take care,
Jay F.

[oldpueblo]

Originally Posted by MasterMech77

Just a bit of info... I see the RCA wires run with the power. This is never a good idea, the reason is the magnetic flux you get off of the power wires really plays havoc with you sound signal. Even a good twisted pair of RCAs will be effected in the long run. Best thing to do is run the power on one side and the audio on the other side of the vehicle.

The other thing that could happen is say God forbid, but you have a short in the main power wire you will not have to worry about it buring a hold in to your RCAs and shorting out the inputs on your amp. A short to ground is bad too, but most amps have fuses there to protect themselves, but not in the RCA side of things.

Just something I noticed a lot of people don't think about or know when they run the wires for the Subs. That and I never like to see anything bad happen to our babies

Take care,
Jay F.

You are absolutely right, in my case though the power is the only line run to the front of the car. The RCA go to an adapter spliced into the amp directly below. They just look like they're run together, but really just end up in the same place. Good tip though.