Audio system: Subwoofer compatibility and installation

[PhatFreshPrince]

Originally Posted by soundman98

yea, while it might technically work, i personally don't trust the oem wiring--it was designed around a lower power amp, and a lower power output level as well. could it work? sure. but is it worth it to install a $250+ amp over the course of roughly 2-4 hours, only to have to tear into everything at a later date because the factory wiring turns out to be too thin to offer the benefits of the amp you already paid for?

if you're going to amplify the speakers, the oem speaker wire is only something like 18-20gauge wire. i personally go a little overkill running 12-13ga, but i wouldn't push 50wrms into anything less than 16 gauge pure copper wire from a known-good supplier like crutchfield or knukonceptz. so once you're replacing the speaker wire to take full advantage of the amp, it's not even a full hop-skip-and-jump more to run a dedicated power line, as most of the panels that need pulled for the speaker wire need pulled for the amp cabling.


there's some newer conflicting info on that.
on the .org /threads/sub-amp-install.1516/page-2#post-44632
remove donut has tested/measured the oem signal and says it's really just a low level signal. so any amp should work just fine. most quality amps are going to have a high level input option anyways.



the oem amp is a 'dumb' amp, it doesn't handle any specialty features, same as any aftermarket amp.

I tested the speaker over the weekend and this is what I found.

1) Unplugging the tweeter does not kill the door speaker, but it does kill the other 3.5-inch dash speaker that is right next to the tweeter.

2) Metering the tweeter it shorts pins 1 and 2 on the hardness you suggested here: https://tacotunes.com/shop/toyota-ca...ness-adapters/

3) I am reading 7.0 volts DC on pins 2 and 4, and 1 and 3 pins go to the 3.5-inch speaker in the dash. With the tweeter shorting pins 1 and 2 this provides a signal to the 3.5-inch speaker. I am not sure how they are grounded.

Does this make my plan harder or easier to wire up? I could NOT install the crossovers and new tweeters in the dash and just replace the 6.5-inch speakers in the door. I guess I need to pull out the head unit to see what I have access to back there. If I put the crossovers behind the head unit then the 3.5-inch speaker with get filter as a tweeter. What do you suggest?

[soundman98]

Originally Posted by PhatFreshPrince

I tested the speaker over the weekend and this is what I found.

1) Unplugging the tweeter does not kill the door speaker, but it does kill the other 3.5-inch dash speaker that is right next to the tweeter.

2) Metering the tweeter it shorts pins 1 and 2 on the hardness you suggested here: https://tacotunes.com/shop/toyota-ca...ness-adapters/

3) I am reading 7.0 volts DC on pins 2 and 4, and 1 and 3 pins go to the 3.5-inch speaker in the dash. With the tweeter shorting pins 1 and 2 this provides a signal to the 3.5-inch speaker. I am not sure how they are grounded.

Does this make my plan harder or easier to wire up? I could NOT install the crossovers and new tweeters in the dash and just replace the 6.5-inch speakers in the door. I guess I need to pull out the head unit to see what I have access to back there. If I put the crossovers behind the head unit then the 3.5-inch speaker with get filter as a tweeter. What do you suggest?

i would suggest getting rid of the 3.5" speaker as part of the speaker change.

yeah, i think the best option here would be to install the crossovers behind/to the side of the radio. i would run wire through the dash to the new tweeters, and then use a combination of these 2 harnesses to grab the audio signal from the head unit, and then use the other harness to plug into the oem wiring to connect to the door speakers, and then make an amp bypass harness so the factory amp filtering isn't messing with the new speakers.

https://metraonline.com/part/71-1761...udio&Year=2018

https://metraonline.com/part/70-1761...udio&Year=2018

[PhatFreshPrince]

Originally Posted by soundman98

i would suggest getting rid of the 3.5" speaker as part of the speaker change.

yeah, i think the best option here would be to install the crossovers behind/to the side of the radio. i would run wire through the dash to the new tweeters, and then use a combination of these 2 harnesses to grab the audio signal from the head unit, and then use the other harness to plug into the oem wiring to connect to the door speakers, and then make an amp bypass harness so the factory amp filtering isn't messing with the new speakers.

https://metraonline.com/part/71-1761...udio&Year=2018

https://metraonline.com/part/70-1761...udio&Year=2018

Okay, thanks. I have the other two harnesses on order.
What do you think about this? Moving the 3.5" 4 ohms speaker from the dash and replacing the 3.5" 6 ohms speaker in the back. I think the back speakers are 6 ohms from what I have read. Will it help the sound quality any, and is it worth the work?


Sent from my iPhone using Tapatalk

[jimmyjazz86]

Originally Posted by soundman98

yea, while it might technically work, i personally don't trust the oem wiring--it was designed around a lower power amp, and a lower power output level as well. could it work? sure. but is it worth it to install a $250+ amp over the course of roughly 2-4 hours, only to have to tear into everything at a later date because the factory wiring turns out to be too thin to offer the benefits of the amp you already paid for?

if you're going to amplify the speakers, the oem speaker wire is only something like 18-20gauge wire. i personally go a little overkill running 12-13ga, but i wouldn't push 50wrms into anything less than 16 gauge pure copper wire from a known-good supplier like crutchfield or knukonceptz. so once you're replacing the speaker wire to take full advantage of the amp, it's not even a full hop-skip-and-jump more to run a dedicated power line, as most of the panels that need pulled for the speaker wire need pulled for the amp cabling.


there's some newer conflicting info on that.
on the .org /threads/sub-amp-install.1516/page-2#post-44632
remove donut has tested/measured the oem signal and says it's really just a low level signal. so any amp should work just fine. most quality amps are going to have a high level input option anyways.



the oem amp is a 'dumb' amp, it doesn't handle any specialty features, same as any aftermarket amp.

Personally feel like anything more than 16-18AWG is overkill for car audio. You are pushing at most, what 200w down a single line? Even for massive line arrays we use 10-12awg conductors for a single box and those can regularly push thousands of watts peak per cabinet, with RMS typically between 300-1200w.

[soundman98]

Originally Posted by PhatFreshPrince

Okay, thanks. I have the other two harnesses on order.
What do you think about this? Moving the 3.5" 4 ohms speaker from the dash and replacing the 3.5" 6 ohms speaker in the back. I think the back speakers are 6 ohms from what I have read. Will it help the sound quality any, and is it worth the work?


Sent from my iPhone using Tapatalk

the rear speakers are the same size as the dash speakers. so i wouldn't expect any change in performance.

[PhatFreshPrince]

I am digging into the dash speakers and see they have a 3.5" at 4 ohms speaker and a 1" tweeter at 4 ohms that are connected in parallel. This makes the dash speakers "look" like a 2-ohm speaker to the head unit, but at the same time, it has 4-ohm speakers in the back. I thought this was not a good practice to do. Or is the little 3.5" speaker in the back a 2-ohm speaker as well?

[soundman98]

the dash speakers also have capacitors on them, which only makes them operate part of the time.

it's the same methodology used in household bookshelf 2-way/3-way/4-way designs.

[PhatFreshPrince]

I see the capacitor on the speaker, but that does not reduce the ohms rating correct?
I am asking because I put the 6.5" in the back and wanted to get a 4-channel amp to drive the dash speakers and the two 6.5" in the back. The 6.5" are 4-ohm, so I wanted 4-ohm in the front to make everything the same. I know I could just remove the 3.5" in the dash or just replace them with these:
https://www.amazon.com/gp/product/B0...k_ql_qh_dp_hza
I just did think it was NOT good of the factory to wire the combo 2-ohm in the dash and 4-ohm in the rear. Unless I am missing something?

[soundman98]

that's a question for someone with an electrical/audio engineering degree.

all multi-frequency/multi-speaker/divided network systems operate identical to that, and no one's really given me a reasoning for why, but over 5 decades of operation of other systems indicate you won't have issues.

[jimmyjazz86]

Originally Posted by soundman98

that's a question for someone with an electrical/audio engineering degree.

all multi-frequency/multi-speaker/divided network systems operate identical to that, and no one's really given me a reasoning for why, but over 5 decades of operation of other systems indicate you won't have issues.

Basically, the capacitor acts as a cheap passive high pass filter that allows only the higher end of the audio spectrum into the speaker. It's how you get most speakers in multiway boxes to only reproduce their specific frequencies (infra/sub/mid/tweeter). besides just tuning the diaphragm of the driver itself.



The capacitor works like this because their impedance values can fluctuate across the frequency spectrum, only allowing those in certain frequency bands to pass through between the plate and dielectric layers.

[soundman98]

Originally Posted by jimmyjazz86

Basically, the capacitor acts as a cheap passive high pass filter that allows only the higher end of the audio spectrum into the speaker. It's how you get most speakers in multiway boxes to only reproduce their specific frequencies (infra/sub/mid/tweeter). besides just tuning the diaphragm of the driver itself.



The capacitor works like this because their impedance values can fluctuate across the frequency spectrum, only allowing those in certain frequency bands to pass through between the plate and dielectric layers.

in a 'typical' 6db/oct crossover arrangement, the woofer will be 'acoustically' crossed over, ie, no additional components, and the tweeter will have a capacitor across it for a 6db/oct rolloff.

in this arrangement, at higher frequencies, doesn't the combined 4ohm woofer and 4ohm tweeter present to the amp as a 2ohm load?

[PhatFreshPrince]

@soundman98,
I have a technical question about amps. Why do the HPF and LPF on the cheaper amp only go from 40Hz to 500Hz for both the high and low filtering?
I did find one (Rockville), so far that goes from 15Hz to 4000Hz. This seems like it will be a lot more flexible in what frequencies are sent to what speakers. Does it really make a difference? I guess the speaker can really take and sound good with more frequencies than the amp industry would like for everyone to think.

[soundman98]

40-500hz is a more typical/expected crossover range. most sound systems are usually crossed over around 80-200hz between the subwoofer and midrange speakers. and most 2-way door speakers have their own built-in crossovers for the tweeters.

so there's really just no need for the crossovers need to span a much larger range most times, especially if they can undercut their competitors on component costs by going with the more standard speaker arrangements.

[OkieSnuffBox]

Originally Posted by soundman98

in this arrangement, at higher frequencies, doesn't the combined 4ohm woofer and 4ohm tweeter present to the amp as a 2ohm load?

Depends on how you wire it. I don't know enough about how the stock wiring is setup to know.

If you take two, 4 ohm speakers and wire them in parallel you get a 2ohm load to the amp. So it pulls more power and isn't an issue as long as your amp is rated for that load.

The two same speakers wired in series put an 8ohm load to the amp.


That said, I'm just going to wait for the OEM Audio+ setup to be available for 2nd gens. The full kit, not just the front speakers.