How to use the OEM amp Wiring

[rixter145]

Sooo totally went another direction. Decided to get this sub that comes with an amp already:
https://www.amazon.com/Cerwin-Vega-P...1878664&sr=8-5

Now the real question is... how do I apply a lopass filter to the front speakers since I ideally want to have this sub handle all the low frequencies. Unless this is not really needed?
Is there something that I can put for pin 1,2,5,6 ?

This sub has no out and I am envisioning installing this by tapping the stock wiring harness (pins 3,4,9,10) as hi level inputs

[FR-S2GT86]

Originally Posted by rixter145

Sooo totally went another direction. Decided to get this sub that comes with an amp already:
https://www.amazon.com/Cerwin-Vega-P...1878664&sr=8-5

Now the real question is... how do I apply a lopass filter to the front speakers since I ideally want to have this sub handle all the low frequencies. Unless this is not really needed?
Is there something that I can put for pin 1,2,5,6 ?

This sub has no out and I am envisioning installing this by tapping the stock wiring harness (pins 3,4,9,10) as hi level inputs

If your head unit has low level RCA outputs, you need to find out how many, and if they have any built-in crossovers that you can set inside the the unit. Having a dedicated subwoofer RCA output will be beneficial to you in this situation as you can now run that signal to your new spare-tire sub/amp combo.

If you're still running the OEM amplifier to power the door speakers, remember that there are no adjustments that you can make with it. It has no gain control, the low pass filter is fixed and the subsonic filter is fixed if it has one. If you make any major changes to your system, the OEM amp becomes pretty much useless unless you want to spend even more money to properly integrate it.

If your deck is powering the front speakers (the dash mids and tweeters) only, and if your deck has front crossover capabilities that carry over not only from the RCA outputs, but also to the speaker outputs, you may be in luck. But then you would have to find a way to supply a non- filtered signal to the OEM amp or you're door speakers will be attempting to play the same frequencies that you are trying to make your front speakers play. But since there is a low pass filter in the amp, you won't get much out of the door speakers.

Give us the brand and model number of your head unit and we will find the installation/operator's manual for it and let you know what kind of options you will have. That's the best way we can offer help.

*Edit* Your front OEM speakers already have a 6db/octave passive crossover to filter out the lower frequencies that they shouldn't be playing. The OEM door speakers and amp work together as a team along with the front speakers to form a three-way front stage.

[rixter145]

Originally Posted by FR-S2GT86

If your head unit has low level RCA outputs, you need to find out how many, and if they have any built-in crossovers that you can set inside the the unit. Having a dedicated subwoofer RCA output will be beneficial to you in this situation as you can now run that signal to your new spare-tire sub/amp combo.

If you're still running the OEM amplifier to power the door speakers, remember that there are no adjustments that you can make with it. It has no gain control, the low pass filter is fixed and the subsonic filter is fixed if it has one. If you make any major changes to your system, the OEM amp becomes pretty much useless unless you want to spend even more money to properly integrate it.

If your deck is powering the front speakers (the dash mids and tweeters) only, and if your deck has front crossover capabilities that carry over not only from the RCA outputs, but also to the speaker outputs, you may be in luck. But then you would have to find a way to supply a non- filtered signal to the OEM amp or you're door speakers will be attempting to play the same frequencies that you are trying to make your front speakers play. But since there is a low pass filter in the amp, you won't get much out of the door speakers.

Give us the brand and model number of your head unit and we will find the installation/operator's manual for it and let you know what kind of options you will have. That's the best way we can offer help.

*Edit* Your front OEM speakers already have a 6db/octave passive crossover to filter out the lower frequencies that they shouldn't be playing. The OEM door speakers and amp work together as a team along with the front speakers to form a three-way front stage.

Thank you, I got some chinese android head unit, and I remember the back has no additional RCA outs sadly... it was made for our car so it uses the stock harness.

For the '6db/octave passive crossover' - how does that work exactly? Does it reduce 6db at 100 hz?
I think at this point, I will just keep it simple with the stock amp and tap in the signal wires and put them in as hi level inputs

[FR-S2GT86]

Originally Posted by rixter145

Thank you, I got some chinese android head unit, and I remember the back has no additional RCA outs sadly... it was made for our car so it uses the stock harness.

For the '6db/octave passive crossover' - how does that work exactly? Does it reduce 6db at 100 hz?
I think at this point, I will just keep it simple with the stock amp and tap in the signal wires and put them in as hi level inputs

I can't remember exactly what frequencies the OEM mids and tweets are crossed over at, but if you know the value of the capacitors in line with each driver, you can look them up using a chart or calculator. Here is a calculator that can help you:

https://www.the12volt.com/caraudio/p...ulator.asp#ccc

Scroll down the page about halfway and input information for 4-ohm speakers.

If you're just adding a sub and that's all, determine if you want the sub to fade with the front speakers or with the rear speakers. If you want it to fade with the front, make sure you tap the signal input leads to the factory amp for your signal, since that will be a full-range signal to work with. Also, make sure to connect them in phase with each other to the subwoofer amp input, or else the two signals will cancel each other out and you will have almost no bass output from your sub. It will also help if you can make sure that the output of the sub is in phase with your door speakers to help eliminate bass cancellation between the sub and doors speakers.

The same rules apply for tapping into the rear speakers if you want your sub to fade with them instead.

@soundman98, I did some experimentation last week with the factory amp if you're interested in the data. I measured the signal voltage in and compared it to the speaker voltage out with minimal to no clipping at several different frequencies trying to keep the same input voltage at all times. I ended up making about 5 different measurements of both the inputs and outputs at each frequency, then averaged them all up to get the best results. Haven't gone to the trouble to graph it all out, and it's not hugely representative of the frequency spectrum, but it might be useful to somebody. Just let me know and I'll post it later tonight or first thing tomorrow.

[NickB34]

Originally Posted by rixter145

Sooo totally went another direction. Decided to get this sub that comes with an amp already:
https://www.amazon.com/Cerwin-Vega-P...1878664&sr=8-5

Now the real question is... how do I apply a lopass filter to the front speakers since I ideally want to have this sub handle all the low frequencies. Unless this is not really needed?
Is there something that I can put for pin 1,2,5,6 ?

This sub has no out and I am envisioning installing this by tapping the stock wiring harness (pins 3,4,9,10) as hi level inputs

The sub has a low pass filter. Just tap into the stock amplifier wiring harness and send it the full range signal.

Sent from my SM-N970U using Tapatalk

[soundman98]

Originally Posted by FR-S2GT86

I can't remember exactly what frequencies the OEM mids and tweets are crossed over at, but if you know the value of the capacitors in line with each driver, you can look them up using a chart or calculator. Here is a calculator that can help you:

https://www.the12volt.com/caraudio/p...ulator.asp#ccc

Scroll down the page about halfway and input information for 4-ohm speakers.

If you're just adding a sub and that's all, determine if you want the sub to fade with the front speakers or with the rear speakers. If you want it to fade with the front, make sure you tap the signal input leads to the factory amp for your signal, since that will be a full-range signal to work with. Also, make sure to connect them in phase with each other to the subwoofer amp input, or else the two signals will cancel each other out and you will have almost no bass output from your sub. It will also help if you can make sure that the output of the sub is in phase with your door speakers to help eliminate bass cancellation between the sub and doors speakers.

The same rules apply for tapping into the rear speakers if you want your sub to fade with them instead.

@soundman98, I did some experimentation last week with the factory amp if you're interested in the data. I measured the signal voltage in and compared it to the speaker voltage out with minimal to no clipping at several different frequencies trying to keep the same input voltage at all times. I ended up making about 5 different measurements of both the inputs and outputs at each frequency, then averaged them all up to get the best results. Haven't gone to the trouble to graph it all out, and it's not hugely representative of the frequency spectrum, but it might be useful to somebody. Just let me know and I'll post it later tonight or first thing tomorrow.

honestly, i'm most interested in if the oem amp could be easily/simply altered to better fit everyone's needs that want to deviate from the as-shipped settings.

[rixter145]

Wrt aftermarket amps, I stumbled upon Nick from Etsy who does 3d bracket printing for those who want to pursue that option
https://www.etsy.com/ca/listing/8164...p_home_recs_10

He also does brackets for door speakers/tweeters/rear speakers as well. So if I am going for aftermarket, I will def be getting those from him

[FR-S2GT86]

Originally Posted by soundman98

honestly, i'm most interested in if the oem amp could be easily/simply altered to better fit everyone's needs that want to deviate from the as-shipped settings.

I'll pull it out, disassemble it in the next day or two and see what I can find then get back to you.

[soundman98]

Originally Posted by rixter145

Wrt aftermarket amps, I stumbled upon Nick from Etsy who does 3d bracket printing for those who want to pursue that option
https://www.etsy.com/ca/listing/8164...p_home_recs_10

He also does brackets for door speakers/tweeters/rear speakers as well. So if I am going for aftermarket, I will def be getting those from him

Link doesn't work anymore

[soundman98]

Originally Posted by FR-S2GT86

I'll pull it out, disassemble it in the next day or two and see what I can find then get back to you.

You're much more motivated than I am

[rixter145]

Originally Posted by soundman98

Link doesn't work anymore

Try this:
https://www.etsy.com/shop/Fusion3Dll...g_id=816473559

Or search up Fusion3Dllc on etsy

[philly_tee]

Well I’m late to the party… ��

Just picked up my 2014 brz this spring and Like ya’ll I’m over the sound quality of the audio system.

I’m about to do amp swap with the alpine. I’m going to update my door speakers as well with focal ec165 coaxial. I also have the stock oem kicker sub in there (that will go soon), I guess I’m wondering if adding this alpine will do anything negative to the car or power since there is a sub and amp already.

Also, is there a fix for the ground wire static issue?

[soundman98]

imo, it's much better to run a new power wire from the battery.

things can be cobbled together with the oem wiring, but at the level of effort of replacing the speakers and the amp, it's really better to just replace the wiring as well to get the most out of the new parts.

what kind of 'ground static' are you experiencing?

[philly_tee]

Are you saying run a new power wire from the battery for this alpine unit?

I’m not experiencing any ground static as I’m yet to do the install. But from what I’ve been reading in the pages of this thread there seems to be an issue with static from the ground wire.

The oem kicker sub plugs into the back of the head unit and powers through the wiring harness. It’s sounds ok but now the doors and tweeters are falling behind.
I’m going to try this first and see if this helps complete the sound.

If not, then full build ahead this summer.

I just need more volume and omphh from the door speakers and tweeters.

Originally Posted by soundman98

imo, it's much better to run a new power wire from the battery.

things can be cobbled together with the oem wiring, but at the level of effort of replacing the speakers and the amp, it's really better to just replace the wiring as well to get the most out of the new parts.

what kind of 'ground static' are you experiencing?