Audio system problems help! Replacement Speakers + New Amp

[Pucker5]

I installed my sound system back in March and I had the same dilemma on whether or not I should remove the factory radio. It was a huge headache because I realized that the factory radio, head unit, and navigation are all tied together in grounds. I ended up dropping the project and left factory radio in place and just used the wires exiting the factory radio into a LOC then to an aftermarket amp.

The only thing I can really say I can't stand is the hissing sound the speakers have when you turn on the head unit. Did you have this issue? or rather do you hear this now with your factory amp back in place? OP

Here was my original thread if you want to take a look.

2005 Toyota LC Audio System Upgrade

Btw I never commented, you were so thorough in that wiring explanation. Few have gone that deep to explain their troubleshooting journey. Did you ever correct that noise? That loc hiss is what numerous other car audio report in the audiocontrol products in Toyota as well as non Toyota integrations. But also it could amplified by signal interference (random thin shielded wire too close to metal). If anyone can find a Jbl ms8 processor that would likely play quite nicely with a factory jbl integration.

 

[SquareOne]

Btw I never commented, you were so thorough in that wiring explanation. Few have gone that deep to explain their troubleshooting journey. Did you ever correct that noise? That loc hiss is what numerous other car audio report in the audiocontrol products in Toyota as well as non Toyota integrations. But also it could amplified by signal interference (random thin shielded wire too close to metal). If anyone can find a Jbl ms8 processor that would likely play quite nicely with a factory jbl integration.

I apologize for taking so long in my response. I never found the problem. The wire harness that I used for the aftermarket amp is shielded and insulated, so that elminates the idea of signal interference.

I honestly think it's the way the system works and how everything is integrated (Head Unit = Amplifier = Nav, take one out of the equation it goes haywire). After lurking through the forums for awhile I realized this is a ground issue and ground is transfered among the three mentioned above.

When I get the chance I'm going to bypass the amp completely and then use these wires based on what others posted:

SGND = (-) wire for all the speakers (I think this is the correct wire for the negative inputs, I gotta test it.)
RL = (+) REAR Left
RR = (+) REAR Right
FL = (+) FRONT Left
FR = (+) FRONT Right

HEAD UNIT GND = Spliced together with AMP E and GND2 (ground wires from AMP to complete the ground circuit)

I'll lose the NAV ECU sound, but what I'll end up doing is splicing the BEEP wire (from the HEAD UNIT, I believe the BEEP wire is a positive wire for the speaker since it comes out on the left side, but I gotta test this one.) with the positive wire (AUO +) coming from the NAV ECU, and then I'll connect the outputs (AUO -) and (AUO +) to a small speaker like a tweeter. The NAV ECU has its own power based on what I seen on the electrical papers, so it should be sufficient to power a small speaker. Again, I gotta test this out to say it works, I'm just thinking it works.