The user manual specifications section under Audio Outputs says, "4V line level front & rear stereo phono (RCA) line jacks, 1V stereo phono (RCA) line jacks on chassis."

Now, my question is, when I hook it up to the RCA inputs on my headunit, is the output from the Rio Car 1V or 4V?

Greetings!

If you are going from the bare empeg / RioCar, 1V. If you are hooking up the car sled wiring to your home system, 4V.

Thanks for the reply. Can you tell me why there is a difference between the two?

Greetings!

Basically, the design was for audiophile use. The 4V outputs in the car can give a much better signal to noise ratio. The 1V is more standard for home stereo components. There is a little more info in The FAQ.

Thanks!