GreggyG

I have added a set of 10" subwoofers and tapped into the rear speakers to get the signal. Everything worked fine for about a month, then it started to make a loud subwoofer sound during start up, regardless of if the stereo was on or not. The amp manufacturer and the place who sold me everything said that maybe it's a noise cancelling issue with the cabin mics. Could this be true? If so, where are they located to disconnect them, are there any ways to disable them, or, would that sound still occur if I used the signal into the amp from either the fronts or the factory sub instead of the rear speakers? Thanks,

cdew002

Are you saying you hooked up two subs to the stock amp? Regardless of the resolution, that is likely your issue.

And I've personally never heard of noise canceling mics and I would have looked at that guy like he had lost his mind.

GreggyG

no, I'm saying that I have tapped into the signal of the rears, created rca connections for that to input directly into my aftermarket amp, which is powered to the battery, grounded, and has a remote turn on. Then the output goes to the subs. I think the noise canceling thing has to do with a feature that changes the volume of the navigation voice or the blue tooth or something depending on cabin noise?

z0lt3c

iTrader: (1)

It sounds to me like you screwed with the very sensitive impedance levels on the factory amplifier.

I would not take a signal post amplifier. I would split the signal at the pre-amplifier output from the main stereo harness. You can access this harness either at the amp location or stereo head unit location. Note that the pre-amp signal is a BALANCED level type so you will need to unbalance and/or make sure your external amp can accept a balanced level signal. I would suggest a Y cable like this -- The stereo head unit and amplifier are both manufactured by Pioneer and you can find the schematic and pin-outs online. I have the drawings for the navigation based system if you want a copy.

There is a cabin mic located underneath the steering column toward the right hand side. Look for the slotted vent in the plastic trim.

GreggyG

thanks for the suggestion, I would love a copy of the nav based system, my e-mail is gregoryrubin@comcast.net I am not sure if the signal was tapped pre-amp or post amp, I had it installed professionally. do you believe that tapping the signal changed the impedence? (ohms if I understand you correctly)

z0lt3c

iTrader: (1)

Here is the link (again); http://retro-caraudio.servehttp.com/...viceManual.pdf

See page 26 for the pin-out of the head unit. Looking at the diagram on this page, the rightmost 20P connector feeds the amplifier location. You can see you have pre-amp L+,L-,GND and R+,R-,GND -- these are the balanced feeds you want to split with a balanced Y cable.

The GX system runs at a very uncommon 8 ohm (and maybe higher) impedance. This allows the rather small wattage amp to push the large number of speakers in the system. Depending how you are splitting your signal, it could change the impedance, worst case, but in any case, the GX system is extremely sensitive to impedance changes.

I would expect a "professional" to check impedance settings but using a speaker level output to feed a new amplifier install is a corner cutting type of solution.

GreggyG

Major update!!!!

So, I realized that the installer pulled the signal from my rear speakers to use for the amp/sub. I removed the LOC, wired a set of RCA's directly to the speaker wires of the factory sub, using the sub signal and disconnected the factory sub. Not only did that fix the problem but it made the subs so strong/loud that it was as if I added 4 subs to the system. Now it is working so well that I am just using one sub and it's way louder/deeper than when I was using both subs coming off of the rear signals. Thanks for the input/suggestions. I just wanted to pass this along.