2020 86 Stereo Info

[FR-S2GT86]

Originally Posted by Greg_2086

I preface this with I have not taken apart my dash yet, but stumbled across while digging into whether the front dash and door speakers are wired in parallel or series and how the rear amp jumper might impact impedance versus using the amp.

If this unused connector still exists in the 2020's, it might minimize the adapter harness FR-S2GT86 is making for the no-cut factory wire/adapter harness solution since the antenna adapters would no longer be needed.

Possibly D29 Option Connector in the wiring image below?

Given that the antenna turn-on and amp turn-on are energized when the vehicle is in ACC or ON and whether the head unit is manually on or off versus being controlled by the head unit (referring to FR-S2GT86's post #140) this might be another source to tap the amp turn-on into instead of the antenna turn-on.

Maybe oddrelic or FR-S2GT86 could test the functionality of this?
.

The tweeters and 3" mid-range drivers in the dash are indeed wired in parallel to each other and are normally powered by the OEM head unit on the front channels.

The factory also taps off of those speaker circuits and sends that full-range speaker level signal back to the door speaker amplifier in the trunk, where it either:

(a) feeds the amplifier it's signal, then gets filtered and amplified and then sent back up to the door speakers, or

(b) it gets immediately sent back up to the door speakers through the bypass harness, unfiltered and unamplified.

The problem with the situation described in (b) above is that now the head unit has to bear the burden of two extra 2-ohm speakers, which makes them sound like crap. In reality, according to some here, it makes the entire system sound like crap, and I would suspect the reason behind this is that the front outputs of the head unit are distorting due to a low damping factor in the built-in head unit amp. Most aftermarket amplifiers aren't even stable at loads less than 2 ohms in stereo mode, let alone factory head unit amplifiers.

The guy in the video that you posted was installing an aftermarket head unit, which has the necessary antenna/amplifier turn-on outputs. The Harman head unit does not have a turn-on lead that matches up to the amplifier turn-on wire in the dash harness, which still requires us to use the antenna turn-on lead to power up the amplifier which will still require an integration harness to use, if cutting and tapping wires in your vehicle is a problem for you.

The one special feature of the antenna turn-on lead coming out of the head unit is that after you turn off the vehicle, there is a slight delay, before the head unit de-energizes that turn-on lead (See @oddrelic's description of the delay in post #136). If you use an ACC controlled wire to turn on and turn off the amplifier, it de-energizes it immediately, with no delay, and you will hear strange things, like what @trueno86power described in his latest comment above, (post #153) which is what using the antenna turn on lead instead should solve.

Perhaps I'm misunderstanding your inquiry?

[Greg_2086]

Thank you for the informative wiring/impedance information, which is what/why I was looking into it and what I was able to conclude. It would seem by using the jumper in the 2020's the door speakers become parallel with the dash tweeters and mids already parallel at 2 ohms...thus the head unit front channels are driving 1 ohm. Theoretically increasing power, but more likely causing other issues like heat, distortion, etc. in addition to the fact the door speakers are no longer using the trunk amp low-pass filter.

I was just sharing that the person in the video found an unused 6-pin harness (in addition to the rear speaker 6-pin harness) with a 12v turn-on. Possibly providing a way to make an adapter harness using only 10 and 6-pin adapters. But like you and trueno86power mentioned, this turn-on might cause other unwanted issues like noise, etc. if it energizes/de-energizes too quickly.

[FR-S2GT86]

Originally Posted by Greg_2086

Thank you for the informative wiring/impedance information, which is what/why I was looking into it and what I was able to conclude. It would seem by using the jumper in the 2020's the door speakers become parallel with the dash tweeters and mids already parallel at 2 ohms...thus the head unit front channels are driving 1 ohm. Theoretically increasing power, but more likely causing other issues like heat, distortion, etc. in addition to the fact the door speakers are no longer using the trunk amp low-pass filter.

I was just sharing that the person in the video found an unused 6-pin harness (in addition to the rear speaker 6-pin harness) with a 12v turn-on. Possibly providing a way to make an adapter harness using only 10 and 6-pin adapters. But like you and trueno86power mentioned, this turn-on might cause other unwanted issues like noise, etc. if it energizes/de-energizes too quickly.

You can take an actual resistance measurement of each parallel speaker circuit at the amplifier. Take a look at this diagram, which represents the ten-pin vehicle harness at the amp: (ignore the wire colors in this example, go by pin positions)



With the male end of the vehicles’ ten-pin amplifier connector plugged into the female bypass plug, if you measure across any of the pin circuits indicated with different color arrows at the wire side of the plug, you should get the total resistance load measurements of that circuit.

For instance,

Measuring across the two pins indicated by the blue arrows or the black arrows will give you the value of the total resistance load for the right side front speaker circuit.

Measuring across the green or the white arrow-indicated circuits will give you the value of the total resistance load for the left side front speaker circuit.

All three speakers for each side are wired in parallel with the bypass plug in place. I would be interested in knowing what those measurements are.

[LimitedSlip]

Originally Posted by FR-S2GT86

You can take an actual resistance measurement of each parallel speaker circuit at the amplifier.

Since an ohmmeter is uses a battery as a voltage source this will give you the DC resistance of the circuit under test which is to say the resistance at 0 Hertz. What would be of more interest is a graph of circuit impedance (the vector sum of capacitive and inductive reactance along with resistance) from 20 Hertz to 20 Kilohertz. Not as easy to come by but much more indicative of amplifier load across the audio spectrum.

[86-75309]

Originally Posted by LimitedSlip

Since an ohmmeter is uses a battery as a voltage source this will give you the DC resistance of the circuit under test which is to say the resistance at 0 Hertz. What would be of more interest is a graph of circuit impedance (the vector sum of capacitive and inductive reactance along with resistance) from 20 Hertz to 20 Kilohertz. Not as easy to come by but much more indicative of amplifier load across the audio spectrum.

Speaker impedance will vary quite a bit with frequency. As I recall from my past life working with professional sound reinforcement equipment, a typical 8 ohm rated speaker would register in the neighborhood of 6.2 ohms of DC resistance. I'm guessing a 2 ohm speaker array would be around 1.55 ohms and a 1 ohm speaker array would measure around 0.77 ohms on a meter. I'm surprised there are 2 ohm car audio components, but I've been disconnected from audio for a few decades. Back in my day, 2 ohms was dangerously close to a dead short and was to be avoided at all costs.

[FR-S2GT86]

Originally Posted by LimitedSlip

Since an ohmmeter is uses a battery as a voltage source this will give you the DC resistance of the circuit under test which is to say the resistance at 0 Hertz. What would be of more interest is a graph of circuit impedance (the vector sum of capacitive and inductive reactance along with resistance) from 20 Hertz to 20 Kilohertz. Not as easy to come by but much more indicative of amplifier load across the audio spectrum.

It would be nice to have an impedance meter that can measure a circuit of multiple parallel speakers in a sweep from 10Hz to 20kHz and display a graph of the results.

[FR-S2GT86]

I have finally completed the DIY for building and installing the plug-and-play harness for re-integration of the OEM door speaker amplifier into the Harman audio systems, see the first post in this thread here,
https://www.ft86club.com/forums/show...11#post3446011

[Tcoat]

Originally Posted by FR-S2GT86

I have finally completed the DIY for building and installing the plug-and-play harness for re-integration of the OEM door speaker amplifier into the Harman audio systems, see the first post in this thread here,
https://www.ft86club.com/forums/show...11#post3446011

If you have one of these units go to his DIY.

GO THERE NOW.
Don't wait.
Don't fart around.
Go there.

[Greg_2086]

Now that I have completed the wiring modification to use the trunk mounted door speaker amplifier, I wanted to update that I also looked to see whether the existing 24-pin connector is still present in my 2020 86 wire harness as far as a plug and play solution for the reverse camera on the 2020 Harman head unit (referencing vitriumGTS post #22, reh8388 post #34, and trueno86power post #44). Unfortunately it is not...so a more complex modification is still needed to bring it down from the rear view mirror to the head unit.

[nettech_gt]

I have not been able source a company that will ship a Kenwood DDX919WS to the US... Can some verify the 2020 86 headunit will work in a 2017 BRZ with an OEM Audio+ system? Plug in play? Thanks.

[FR-S2GT86]

Originally Posted by nettech_gt

I have not been able source a company that will ship a Kenwood DDX919WS to the US... Can some verify the 2020 86 headunit will work in a 2017 BRZ with an OEM Audio+ system? Plug in play? Thanks.

I'm certain that we can get it to work, but if it's the Harman head unit that you're wanting to install, we'll have to make a few minor modifications.

[nettech_gt]

Yes, I want to install the model with Car play/AA. What type of modificats are needed? Thanks.

[FR-S2GT86]

Originally Posted by nettech_gt

Yes, I want to install the model with Car play/AA. What type of modificats are needed? Thanks.

Speaker level signals from the Harman head unit are relatively the same as the original '17 OEM head unit, so those will connect up and work just fine. The amplifier output for the Harman head unit, however is a negative output and won't turn your amplifier(s) on. It will end up popping the head units' fuse, so you'll have to de-pin the amplifier turn-on wire from the 10-pin harness behind the head unit and use the antenna output wire to power both the powered antenna and your amp(s).

Here is a DIY write-up on that which you can use as a guide:

https://www.ft86club.com/forums/showthread.php?t=145959

Make sure to read the link on installing the new Harman head unit that Toyota provided their dealers which is included in the write-up as you will have more plugs and harnesses to have to deal with than what my DIY write-up addresses.

The only differences in your car will be the lack of the yellow bypass harness at the OEM amplifier in the trunk so you won't have to worry at all about re-integrating the factory door speaker amp. And you might also have to install the newer single trim piece to fit around the head unit. Just make sure you try and physically fit it into the dash with your existing trim pieces first.

If you have any questions, just post them in that thread and we'll get it all sorted out in there.

[nettech_gt]

Thanks for the guide! Just so we are on the same page, I have a OEM Audio + (Reference 450Q) system. Will your guide still apply? Also will I retain the use of the factory mic and backup camera?


https://oemaudioplus.com/wp-content/...EF450Q_Web.pdf