Could a simple HU swap be this confusing ??
 

I did a good bit of searching the forum and had no luck. I apologize if my first forum post is asking a question that is covered somewhere that I missed.... :search:

I want to run a simple set up with a replacement HU that will work with the OEM amp and feed high pass to the back and front speakers via it's speaker outputs. I want to set the new HU high pass point to cut down the bottom end the OEM amp is sending to the front door woofers. I find that they seem to bottom out and distort before I notice any distortion from the back upper dash mid / high speakers. I will run a modest powered sub amp via the new HU sub out to drive a small sub in the trunk to pick up the bottom end.

When checking Crutchfield to find out what conversion harness I would need, they indicate I have 2 options. The first is a standard harness that is so cheap they give it away with HU purchases. The second is far from cheap and they indicate you must use it to utilize the OEM amp in the FRS. This link will show their options for install kits and what features each will provide.

https://www.crutchfield.com/car/solu...&mode=ShopPath

At first I think the low price install kit will provide what I need but they indicate it won't work with the OEM amp.

I understand what additional features the high dollar install kit provides with the Maestro module. Other than their indication it is needed to utilize the OEM amp, I see none of those features to be of use to me.
I have no steering wheel controls, I would use my phone & OBD2 reader if I want to see gauges, no existing provisions for a Back Up Cam and I can buy a USB adapter cheaply to utilize the OEM port.

Am I condemned to have to cough up the extra $100+ for the iDatalink / Maestro module so to continue using the OEM amp ???

Thanks

I doubt it is important but my OEM HU is what I think is the first generation bespoke / Pioneer touchscreen offered in the FRS as seen in this photo

http://www.sub5zero.com/wp-content/u...on-FR-S-24.jpg

It seems to me you're trying to make the head unit do what essentially an amp or crossover unit should be doing, and trying to force the OEM setup to do it. This is far from a "simple" head unit swap.

By looking at the wiring diagram for the audio setup, it appears that these speakers you want to separate are wired together anyway, so to achieve what you want, you're replacing the audio system. This type of audio control you want isn't typically available on OEM setups.

I guess I should rephrase my question ...

It looks like many simply replace the OEM HU with an after market HU unit in vehicles that have the OEM amp. If the harness they are utilizing in no way connects to the line level outputs of the new aftermarket HU and it works, then the OEM amp works being fed speaker level signals. In my desired setup, I would do the exact same thing except use the high pass option on my receiver which allows the crossover point to be selected. I simply set it so the OEM amp is getting all but the very low end which the door speakers really can't produce well. That low end would then be produced via a separate sub driver / enclosure and sub amp.

For those who really know how the OEM HU and amp function, I guess my question to them would simply be if the OEM HU is feeding speaker level or line level signal back to the OEM amp.

It is hard to imagine it is feeding line level signal without utilizing shielded or perhaps even twisted pair wiring to protect the signal.

The rear amp gets speaker level signal. In the stock configuration, the dash speakers are 2 4ohm speakers per side (tweeter and mid) wired in parallel to yield 2 ohms, each with small caps for crossovers on the speaker itself, and then the front speaker level signal is also wired to the pioneer amp in the rear, which uses it as input, and reproduces the signal to the doors. This setup let them run the dash safely at 2 ohms, and the doors as well off the stock amp, and all safely on 2 channels (left and right)
to achieve what you want simply use a metra harness to connect the new HU to the OEM FR and FL, and set your crossover point, the OEM Amp will respect it.

Exactly, based on your new description. You originally stated you only wanted to modify the levels to the door woofers. If you're looking to limit all the stock speakers, Chimera is dead-on

Thank You
 

Thank You for the replies and I am sorry my first post only muddied up what I was wanting to know.

Chimera, Thanks for the very detailed info.

It is interesting to think that there are cars today that have speaker level fed amps. Anyone else remember "power boosters" from back in the 70's and 80's ??

Funny how just a few days ago I wanted to limit the audio investment in this car which is why I wanted to know if the cheap harness would do. Now I am thinking to go ahead and invest so to use the Maestro module.
I guess that is the nature of the car audio bug. As soon as you decide what your going to get, in the back of your mind your starting to consider going the next step further.

I know exactly what you mean. Currently upgrading from a 2 way passive front setup to a custom 3 way passive setup myself. Justification was simply that the speaker mounts were there..

Probably a wise choice. I have upgraded both the radios in MomHawk's '05 Mustang (with a Shaker 500 system) and our '04 Suburban (which had a BOSE setup and rear entertainment system) using the recommended harnesses and interfaces from Crutchfield. It couldn't have been easier, well with the exception of figuring out the best place for the huge bundle of wires and the black boxes.

The other option would be to look at a newer Scion radio. I replaced my original '13 basic radio with the Pioneer GPS unit from a '14 and have been very happy with it. Plug and play.

Thanks
 

I am anxious to see how much room there is to work within the HU cavity..
I would be tempted to take your suggestion regarding going with a later model HU to keep it simple. I am installing a JVC KW-M730BT so anxious to try some of it's features which I don't think even the newest BRZ - 86 HU offer.

As I recall there was a lot of room behind and above the HU but it's been about 3 years since I had it out.

There was definitely more room than when I crammed the Pioneer AVIC-8201NEX into my '04 Suburban a few months back. I had to take a reciprocating saw and cut out an over engineered radio support for the AC/Delco/BOSE radio with 6cd changer that was there before. Even with that it was quite a Tetris exercise to get all the wiring and the "black box" interfaces that maintain steering wheel controls and system alerting back in the dash.

theres a fairly good bit of room behind the HU, and lots and lots of room to the right (passenger side in USA) behind the dash façade. above the glove box, below the airbag is a deadspace that's effectively a shelf that you can Velcro things to. the space it a little crapped to work with, but its large enough to hold a small amp if you wanted to hide one there. I used to have a xm radio box there

I'm very confused. If you aren't going to use any of the features the Maestro unit is made for (specifically steering controls, CAN bus integration), why are you even buying it? The standard Metra harness connects directly to the exact factory wiring the factory radio uses to send signal.

If you only are looking to use the system for audio, the Maestro unit is literally throwing money away.

See this thread for the use of the Maestro idatalink interface: http://www.ft86club.com/forums/showthread.php?t=107919