Hey guys, heres what I want to do. I have the Infinity 7 speaker system that came with the truck. I want to keep everything stock, and add a new AMP and 2 subs. So that I don't have to buy a Line Output Converter, I am going to be using the AMP'S Level input harness and tap into the speaker wires of the truck. Crutchfield is telling me to tap into the wires AFTER the stock amp not before. Is this correct?

Here is a diagram that I drew that kinda of explains what they are telling me to do.





Thanks!!

 

Looks good. You have to tap into the front speakers, they are the only speakers that don't have a low pass filtering from the Infinity amp. The left front is + dark green/yellow - dark green/light blue. The right front is + gray/yellow - gray/light blue. Good luck!

 

BTW I mean front door speakers, not front dash speakers. The reason you can't tap in before the amp is that the radio sends a constant amplitude signal to the amp and the amp controls the volume. This is doneusing a CAN bus communication protocol between the radio and the amp.

 

Hey folks, new to the forum and have a question related to this post. I have 08 QC with 7 spkr infinity. I bought the amplified MTX subwoofer system and installed per their directions. Apparently there is something sending signals thru the factory speaker wires when the ignition is off because a short time after opening or closing a door, the subs will buzz for a split second. I tried LOC's and the buzz stopped but the sound output was weak. MTX says to install a 1000 mf capicator inline to turn off the smart start and then use the remote turn-on. I hooked the MTX up to the rear speaker wires per the MTX instructions. Are the rear speakers really going thru a low pass filter? I shure would like to know so I know if I have to re-wire to the front doors to take advantage of the subs.

Thanks
Tom

 

Hey Tom, welcome!

I tried to use the rear door speakers because they were so easy to access (behind the B pillar trim). With my amp x-overat 130Hz I hadvery little sound from the sub. AfterI tapped into the front speakers it was all good with the same x-over and gain. Check out this thread:
https://dodgeforum.com/m_1098300/tm.htm

 

That could explain why I got very disapointing volume when I used the line out converter. I noticed that the bass seemed to disappear when I adjusted the low pass down below 100 or so. I will try tapping into the door speaker leads, any suggestions as to where this is easiest? Any ideas why the built in amp kicks on when openin or closing a door and then creates the buzz?

 

You can tap in on the connector by the parking brake. Just look for the wire colors. You've got me as to why the amp wouldhave anoutput without the ignition on.

 

I see the wire harness by the parking brake. This also contains the wires for the right door?

Thanks
Tom

 

Thanks to 73Jim, I wired the MTX to the front door speakers. What a difference. I now have the gain almost all the way down and the bass on the HU all the way down. Sounds terrific. I tapped into the left door by the parking brake and the right door behind the right kick panel. No dounbt about it, with the 7 spkr infinity, you must tap sub into front doors.