Help!!! After installing Sony AX5000 my subwoofer barely works

[fatboydean]

Hi to all the masters and gurus here, just installed my Sony AX5000 myself on my 2016 BRZ Hikari Edition. Previous owner of the car installed a JL sub with built-in amp in the car. The sub's high level inputs were piggybacked to the factory amp's input. It's low level inputs, which are a pair of RCA connectors, were left unconnected.

Before installing the Sony HU, with stock HU I only need like 10% input sensitivity and it was really powerful and crisp. Now I switched to almost 100% and the sound from the sub is weak and muddy.

Yes I did make a mistake when connecting the factory amp remote wire, after I read in the forum it was corrected(pin 9 from the 10-pin connector). Now I have the factory amp working and door speakers working as well.

I never touched the sub's input circuit so it was unlikely to be a connection problem.

I also tried to connect the low level output from the Sony HU directly to the sub's low level RCA connections. It doesnt work I guess cos Sony HU low level output will not work if the amped outputs are connected? Is there any way to enable the low level output at the same time? I know there is a dedicated sub output, but my sub requires 2 RCA inputs, white and red(it has a low-pass filter), I tried the single output it did not work.

Although the sound quality increased a lot by the Sony HU, without the sub it's still not complete. I would like to make the sub work as well.

Please help! Thank you so much for reading this long post.

[fatboydean]

Just went to the car to take a closer look, my mistake, the sub high level input is tied to the factory amp output. Please see the attached pic. So its really 'high level' since its amped.

Since my door speakers works fine there is really no reason for the sub not working properly. Could it be the Sony HU's power output is lower than the stock HU? Mine is the Fujitsu TEN.

Could it be a bad car battery? I tested the sound system with the car engine running though.

I am offically running out of ideas...

[soundman98]

what model jl sub?

[fatboydean]

Originally Posted by soundman98

what model jl sub?

Not sure the model but here's the pics of the sub

12V power supply, REM both checked n true.
High level input in the pic is tied to the factory amped output of front door speakers.

[soundman98]

you can try to flip the output polarity switch to '0' instead of '180'

is your low pass frequency knob set to 50hz?

and you did connect the blue remote turn-on wire to the radio, right?

the rca jacks should work with one or the other(normally left side is the mono input). i've never heard of an amp that requires both to work.

i don't know enough about sony decks to know what their default configurations are.

[fatboydean]

Originally Posted by soundman98

you can try to flip the output polarity switch to '0' instead of '180'

is your low pass frequency knob set to 50hz?

and you did connect the blue remote turn-on wire to the radio, right?

the rca jacks should work with one or the other(normally left side is the mono input). i've never heard of an amp that requires both to work.

i don't know enough about sony decks to know what their default configurations are.

What value should I use for LP Freq?
Yes remote on also tested 12V so door speakers working fine.I will try again tomorrow to see if the mono input works on mine. I do need to disconnet the high level input first right? I tried using the sony's low level output to test but I got no signal at all, maybe because I was using the AMPed output already... not sure.

So if all those failed it means I broke the sub... right? Any other things I can try?

[FR-S2GT86]

You can try reading the manual of your new Sony head unit for starters and understand how the low level outputs work. You may have to switch them on in the programming section first in order to get any signal output. Then realize that you can only use EITHER the high level speaker inputs for the sub amp OR the low level RCA inputs, but NOT BOTH.

[fatboydean]

Originally Posted by FR-S2GT86

You can try reading the manual of your new Sony head unit for starters and understand how the low level outputs work. You may have to switch them on in the programming section first in order to get any signal output. Then realize that you can only use EITHER the high level speaker inputs for the sub amp OR the low level RCA inputs, but NOT BOTH.

Thanks, I tried to use the sub output from the HU and yes it has a switch in the EQ menu, but mine sub requires 2 RCA and Sony only has one, I tried to use it as MONO but the sub did not respone at all. Next step would be to get a spliter and try it out. If still not working, I will give up and revert back to factory HU.

[FR-S2GT86]

Originally Posted by fatboydean

Thanks, I tried to use the sub output from the HU and yes it has a switch in the EQ menu, but mine sub requires 2 RCA and Sony only has one, I tried to use it as MONO but the sub did not respone at all. Next step would be to get a spliter and try it out. If still not working, I will give up and revert back to factory HU.

Splitting the signal SHOULD fix the problem IF the left and right inputs are required by the sub amp.

After doing that, take note of the subwoofer crossover setpoints in your Sony head unit. I see in the pictures you posted that you have your sub amp crossed over at 50 Hz. Try turning that up to 200 Hz and try to adjust the crossover frequency and slope settings inside your Sony, but get your levels correct first. Unfortunately, the factory amp does not have a gain control on it to allow level matching of the system so you may find that you can turn your new head units' volume control up only part way before running your door speakers into distortion. At that point you may find that you barely have enough low level subwoofer signal to the sub amp and will have to turn the level control up on the sub amp quite a bit to get any decent volume out of it.

My point is, in your system, the weak point is your factory amp due to its' lack of level matching capability.

[FR-S2GT86]

One other possibility is that when you connected the RCA output from the head unit to the sub amp with the high level inputs still connected, you could have fried the RCA output circuitry inside your new head unit.

[fatboydean]

Originally Posted by FR-S2GT86

One other possibility is that when you connected the RCA output from the head unit to the sub amp with the high level inputs still connected, you could have fried the RCA output circuitry inside your new head unit.

Oh that! I made sure it was disconnected!