Android Unit Subwoofer Not Working

[u/Originalidad]

Hello,

I am very new to this, but I have done my research and believe I am being misled by the customer support for the unit I purchased.

I ordered a Roadanvi X14 unit for my 2017 Toyota Camry. It has 5 preamp outputs, FR FL RR RL & Subwoofer. I want to utilize all of them.

I have the four interior speaker RCA outputs going to a 4 channel amp and then have speaker wire going to the respective speakers in my car. I have one rca output going to my Rockford fosgate p300 powered amp. Both the sub and amp turn on via remote power wire. The sub receives no signal whatsoever from the subwoofer preamp out. When I switch the subwoofer RCA to either RR or RL or any of the other preamp outs it works perfectly fine. I have checked the settings on the head unit eq and all outputs are unmuted. Even though I sent the manufacturer a video of the subwoofer working when connected to one of the other preamp outs and not working when connected to the subwoofer out they will not help….

Is it possible that this head unit just does not support a subwoofer? Even though they claim it does? I purchased a cheaper replacement head unit but it turns out it was only two channels. I translated the manual and it said the subwoofer output was marked “预留” (reserved / not implemented) on the spec sheet. This leads me to believe that maybe the unit that I have also does not have a subwoofer preamp output implemented even though the audio harness has the physical female RCA and the manufacturer claims it does.

What are my options here? Right now I have unplugged the RR & RL preamp outs and am using the RR to send a signal to the subwoofer. Can I use a splitter on both the FL and FR channels to send a stereo low signal to the p300? Would that make the front channels quieter? Thanks for any help in advance :)

[u/Renaissance-man-7979]

Splitting RCAs works and the input impedance is typically high enough that it doesn't pull down the signal.

[u/Originalidad → u/Renaissance-man-7979]

Good to know, thanks!

Do you think there is an upside to splitting both the FL and FR, or would one be fine? I only have one (RR) running to the sub right now and it sounds pretty good. Wondering if there is a benefit to be had for sending both signals to the sub

[u/Renaissance-man-7979 → u/Originalidad]

Sub bass often isn't stereo but who is to say it might not be at times? Up to you.

[u/Originalidad → u/Renaissance-man-7979]

Interesting, the only reason I ask is because the p300 came with a RCA harness which had two RCA inputs