How do you put a subwoofer in a Toyota 08 rav4 with a navigation system installed?

I have a 08 Toyota Rav4 with a standard upgrade to the in dash navagation syste which is also my cd player.

How do i connect amps and subs to this. since i have a 4k system just sitting there.

thanksHow do you put a subwoofer in a Toyota 08 rav4 with a navigation system installed?You have a couple of different options and they depend on the money you decide to spend. You can start off by using a Line Level Converter, which is the simplest. All it does is change the sound level you get from the wires that run from the deck to the speakers to something lower for the amp to handle). You could also get into using the newer components that hook into the factory radio that are to an extent an EQ built just for what you want to do. They offer RCA outputs for amplifiers and adjustments to bring out the frequencies that are lost using a factory deck. You are looking at anywhere from 30 dollars or less to over 400 dollars. Again, just depends on what you want to do.