Stereo system

[Tcoat]

Originally Posted by AJ32162

Does this also apply to 2020 Subaru BRZ or is it specific to the 2020 Toyota 86?

I believe it is just the Toyota with the system that has Car Play and Android Auto.
To be specific it is Toyota Part Number: PT296-18190-20

https://www.ft86club.com/forums/showthread.php?t=139286

The biggest problem (as I see it) is that the amp is bypassed and the door woofers are just hooked up with the dash ones. Tis turns what are supposed to be amplified woofers into just plain speakers which are sharing signal with the dash ones.

Easy to check. If you have the jumper connector at the amp in the trunk then your door speakers are weaksauce.

[FR-S2GT86]

Originally Posted by Tcoat

I believe it is just the Toyota with the system that has Car Play and Android Auto.
To be specific it is Toyota Part Number: PT296-18190-20

https://www.ft86club.com/forums/showthread.php?t=139286

The biggest problem (as I see it) is that the amp is bypassed and the door woofers are just hooked up with the dash ones. Tis turns what are supposed to be amplified woofers into just plain speakers which are sharing signal with the dash ones.

Easy to check. If you have the jumper connector at the amp in the trunk then your door speakers are weaksauce.

Why not try removing the bypass plug and reinserting the plug back into the amp and reinstalling the fuse for the amp. There is still signal on the input wires since the signal is tapped into the car side of the harness behind the head unit, right? It can't hurt to try.

[Tcoat]

Originally Posted by FR-S2GT86

Why not try removing the bypass plug and reinserting the plug back into the amp and reinstalling the fuse for the amp. There is still signal on the input wires since the signal is tapped into the car side of the harness behind the head unit, right? It can't hurt to try.

Does not work. You just end up with no door speakers at all. There simply is no separate feed for them from the head unit.

[FR-S2GT86]

Originally Posted by Tcoat

Does not work. You just end up with no door speakers at all. There simply is no separate feed for them from the head unit.

Are your door speakers not working at all currently?

[FR-S2GT86]

Oh!!!

There's no turn-on lead from the new head unit to the amp anymore. That's the problem. There's signal but no turn-on. I'll bet if you can get that amp to turn on, it will help tremendously.

[Ashikabi]

Originally Posted by FR-S2GT86

Oh!!!

There's no turn-on lead from the new head unit to the amp anymore. That's the problem. There's signal but no turn-on. I'll bet if you can get that amp to turn on, it will help tremendously.

Generally turning things on helps them operate. Just tap into the signal for the stereo. Turn em both on at once

Sent from my ONEPLUS A5010 using Tapatalk

[Tcoat]

Originally Posted by FR-S2GT86

Are your door speakers not working at all currently?

My door speakers are on the bypass pigtail as set up by the factory instructions

Originally Posted by FR-S2GT86

Oh!!!

There's no turn-on lead from the new head unit to the amp anymore. That's the problem. There's signal but no turn-on. I'll bet if you can get that amp to turn on, it will help tremendously.

Originally Posted by Ashikabi

Generally turning things on helps them operate. Just tap into the signal for the stereo. Turn em both on at once

Sent from my ONEPLUS A5010 using Tapatalk

It is not as simple as turning on the amp.
There is only one feed for the dash and doors. Now you would have the dash speaker amped when they are not supposed to be. No doubt that would not sound good at all!
There is no simple plug and play corrective action for this.

[LimitedSlip]

Has anyone unearthed the 2020 factory wiring schematics yet?

[FR-S2GT86]

Originally Posted by Tcoat

My door speakers are on the bypass pigtail as set up by the factory instructions





It is not as simple as turning on the amp.
There is only one feed for the dash and doors. Now you would have the dash speaker amped when they are not supposed to be. No doubt that would not sound good at all!
There is no simple plug and play corrective action for this.

There's ALWAYS only been one feed for the dash and door speakers.

You, yourself said further up this thread that you ".....know less than nothing about modern car sound systems....." You still have both mid-range speakers and tweeters in the dash, right?

Trust me on this, the wiring in the car hasn't changed. There is still a full-range signal sent from the head unit to the amp in back since your door speakers are still operating.....only now, since there is a bypass harness connected, they're running at full-range instead of through the low-pass filtering inside your amp as the system was designed originally.

Removing the bypass plug and reconnecting it to the factory amp will NOT amplify your dash speakers as you suspect they will, since those dash speakers are on the SIGNAL side of the amp, not the SPEAKER OUTPUT side. I installed car audio and other mobile electronics professionally back in the late 90's and am now getting back into it with my new build on this current car, and have gotten to know it pretty well. Trust me. It won't hurt to try this simple experiment:

1) Remove the bypass plug at the factory amp location, plug the harness back into your factory amp.

2) Reinstall the fuse that was pulled out in the fuse panel that was removed when the new "upgraded" head unit was installed by the dealer.

3) Jumper the +12 volt amp power supply lead (which now has +12 volts on it there at the amp harness which was non-existent previously due to the fuse being removed) to the amplifier turn-on lead to get the amp to turn on.

4) Turn on your head unit and take a listen.

You should now have a full range signal input to the factory amp again and a low-pass filtered speaker output to your doors.

Let us know how it sounds.

[LimitedSlip]

If I recall correctly the "Harmon Base Audio" head unit was not installed at the factory but at the port of entry or the dealership. If the Harmon head unit worked correctly with the trunk amp, why did Toyota go to all the trouble to produce a technical document and parts kit to facilitate bypassing the amp as part of the Harmon install? There must be some sort of incompatibilty between the HU and trunk amp. Perhaps the speaker level signal from the Harmon is too large for the input of the amp? If using the Harmon/trunk amp combo worked correctly it would have been far less expensive to just go with it rather than bypass it.

Of course, the solution they arrived at doesn't work that well either.

[FR-S2GT86]

Originally Posted by LimitedSlip

If I recall correctly the "Harmon Base Audio" head unit was not installed at the factory but at the port of entry or the dealership. If the Harmon head unit worked correctly with the trunk amp, why did Toyota go to all the trouble to produce a technical document and parts kit to facilitate bypassing the amp as part of the Harmon install? There must be some sort of incompatibilty between the HU and trunk amp. Perhaps the speaker level signal from the Harmon is too large for the input of the amp? If using the Harmon/trunk amp combo worked correctly it would have been far less expensive to just go with it rather than bypass it.

Of course, the solution they arrived at doesn't work that well either.

I would suspect that the "incompatibility" is Harmon convincing someone at Toyota that their head unit "is so much better than your factory-supplied Pioneer unit that you won't need an amp anymore for those door speakers".

The Harmon deck couldn't be MUCH more powerful than the Pioneer deck or else people would be complaining that the dash speakers are too loud or they're blowing tweeters on twins with the Harmon head unit.

The factory amp should be able to utilize that speaker-level signal without much, if any issues.

But until someone tries my experiment (since I can't, or else I would) we won't know for sure. It should only take a few minutes once you identify the two wires, and I believe there are schematics and plug diagrams posted somewhere on this forum.....

And yes, obviously, according to @Tcoat their "solution" didn't work well. So again, I would like to nominate Tcoat to help us all out and confirm for us what I suspect (and help himself out in the process.)

[Ashikabi]

Originally Posted by FR-S2GT86

I would suspect that the "incompatibility" is Harmon convincing someone at Toyota that their head unit "is so much better than your factory-supplied Pioneer unit that you won't need an amp anymore for those door speakers".



The Harmon deck couldn't be MUCH more powerful than the Pioneer deck or else people would be complaining that the dash speakers are too loud or they're blowing tweeters on twins with the Harmon head unit.



The factory amp should be able to utilize that speaker-level signal without much, if any issues.



But until someone tries my experiment (since I can't, or else I would) we won't know for sure. It should only take a few minutes once you identify the two wires, and I believe there are schematics and plug diagrams posted somewhere on this forum.....



And yes, obviously, according to @Tcoat their "solution" didn't work well. So again, I would like to nominate Tcoat to help us all out and confirm for us what I suspect (and help himself out in the process.)

The incompatibility is probably that the Harmon unit has an amp internally and the stock one doesn't. Double amp sounds dicey

Sent from my ONEPLUS A5010 using Tapatalk

[FR-S2GT86]

Originally Posted by Ashikabi

The incompatibility is probably that the Harmon unit has an amp internally and the stock one doesn't. Double amp sounds dicey

Sent from my ONEPLUS A5010 using Tapatalk

If the factory head unit (or any head unit for that matter) can operate speakers directly, then it has internal amplification.

Every factory head unit in these cars was capable of powering speakers. They have ALL been able to run the front mid-range drivers and tweeters as well as rear speakers. None of these head units were strictly pre-amp only.

It should work as I described.

[G_Rossney]

Originally Posted by FR-S2GT86

There's ALWAYS only been one feed for the dash and door speakers.

You, yourself said further up this thread that you ".....know less than nothing about modern car sound systems....." You still have both mid-range speakers and tweeters in the dash, right?

Trust me on this, the wiring in the car hasn't changed. There is still a full-range signal sent from the head unit to the amp in back since your door speakers are still operating.....only now, since there is a bypass harness connected, they're running at full-range instead of through the low-pass filtering inside your amp as the system was designed originally.

Removing the bypass plug and reconnecting it to the factory amp will NOT amplify your dash speakers as you suspect they will, since those dash speakers are on the SIGNAL side of the amp, not the SPEAKER OUTPUT side. I installed car audio and other mobile electronics professionally back in the late 90's and am now getting back into it with my new build on this current car, and have gotten to know it pretty well. Trust me. It won't hurt to try this simple experiment:

1) Remove the bypass plug at the factory amp location, plug the harness back into your factory amp.

2) Reinstall the fuse that was pulled out in the fuse panel that was removed when the new "upgraded" head unit was installed by the dealer.

3) Jumper the +12 volt amp power supply lead (which now has +12 volts on it there at the amp harness which was non-existent previously due to the fuse being removed) to the amplifier turn-on lead to get the amp to turn on.

4) Turn on your head unit and take a listen.

You should now have a full range signal input to the factory amp again and a low-pass filtered speaker output to your doors.

Let us know how it sounds.

I'm trying to get a 2019/2020 Navi/Android Auto HU to work in my 2013 BRZ. I've got all functions working except that door speakers (no low end/bass). I figured the AMP lead from the HU is not making it to the AMP. I thought just getting the AMP powered would solve the issue, but I've searched the wiring diagrams and can't seem to find the wiring diagram for the amp to determine which lead is the lead to turn it on. Is it as simple as a 12v power supply??