I am adding a sub to my car and I am curious on the process that someone would go through to do this. I am going to add a 12" Rockford fosgate sub and a Kenwood amplifier. I am going to fun a remote cable for easy bass adjusting up to the driver's seat. The only problem is I don't know how someone would hook it up to the radio itself. I have the ML system with NAV and all I am doing is adding this sub to it, I'm not changing anything stock whatsoever. how would it work to have it hooked up? Would the volume on the sub be turned up with the radio volume? even though I have the bass remote and controls on the amp itself, will the sub's bass be increased when I increase the Stock system's bass?

What I am trying to say is that I want to control the bass of the stock and the sub separately, (remote vs. controls on the NAV system) but I want the volume of the sub to go up with the radio! Is this possible?

Thanks so much, I really appreciate it if someone can help me with this!

You would need an amplifier with high-level inputs instead of low-level inputs (RCA are low level). Does the Kenwood have speaker level inputs? If not, you need to buy an adaptor to convert the high level inputs to low level in order to have the radio in the dash control the relative volume.

yes he is correct you could use a line out converter also known as a hi to low converter. You would connect it to your factory speaker leads then run the rca's from it to the amp.

Jl audio clean sweep is a beautiful unit but u pay for it ...... FYI u must hook up these units before any factory amp or you will blow *BLEEP* up

I have basically what you are describing. I had the installer put in a hi (speaker level) to low (line level) adapter on the factory sub-woofer. Most of them auto-sense a signal and provide a trigger to turn on your amp.

Although the replies above say the same, I also add that your existing (stock) stereo speakers are "crossed over", meaning that there is a filter that puts only a certain frequency range to the speakers. The larger door speakers may get mid range, there may be smaller tweeters that only get high frequencies. If you tap a "Hi-Low" adapter from these speakers, they are probably filtering out the low frequencies you are trying to pull for your sub. That's why you would put the adapter on a speaker that gets the frequencies you want, like the factory sub. It's only common sense that those larger speakers putting out large sound take a lot of current (power). My first adapter burned out from all that power. It basically melted! Be sure to use a good quality adapter rated for as many watts as you can find. I think cheap ones cost about $15-20 and good ones about $30-40.

I have 2 JL-Audio 10" subs in a sealed box, and a Polk class D sub amp, and it really makes the stereo sound great!