Yes you have been there already on the Amplifier/mixer relatedissue... But what i mentioned about the optional audio device that valentine sells is solving the problem with figuring out which of the wires in the phone jack send the audio signal or trying to convert them into a useable signal. if you say that you must use a mixer to lower the volume of the music when the radar turns on, then just install an independent center channel or another speaker thats main purpose is the for the radar. If its still not loud enough, then throw in a seperate smaller amp to make it louder.

 

Getting the signal from the Valentine is not the issue.

If you're advocating running the signal into its own (amplifier) channel driving a dedicated speaker, sure it'll work. That's two audio systems in one car - one for the radar detector and the other for everything else. We've been here, too.

 

If having two audio systems in one car is too much for you, then purchase the audio adapter like i recommended and then buy other accessories which work in conjunction with the audio adapter (meant for but not limited to motorcycle riders) such as:

The Radar Screamer.
Here is the product description:
"A waterproof 108db pizeo beeper with a hi/med/low volume control that lets you hear an earspeaker-jacked radar detector at speed. Powered by the bike’s 12V system, this setup means no wires to your helmet, no earspeakers, and no external noise problems. Includes complete installation instructions. It’s grab-the-brakes-right-now loud. Specify 2.5mm Valentine or 3.5mm Passport 8500 application."


or the Visual Alert by Marc Parnes (Which I actually own and would recommend)
Its a LED panel which is powered by the remote Audio Adapter VIA the mini headphone jack. If your music is too loud and you cannot hear the radar at all, then how about upgrading the visual alert with this?

"Here's how it works: The Visual Alert plugs directly into the detector's speaker outlet. There are no batteries or complex electronics to wear out or fail. The Visual Alert is powered by the detector's speaker output alone."

These are just some suggestions I thought I'd give to the OP, since no one else here seems to know what aftermarket products there are out there.
-Ryan

 

What? It's not a matter of something being too much for me. It's a matter of what's possible, electrically. The OP's concept simply cannot work, nor can your initial suggestion. The rest boils down to having 2 systems no matter how you slice it. That's all there is to it.

 

OK, so the OP's and my initial concept won't work..... Im sure the other options i mentioned should solve his problem.

 

Just use what I made for my bike. An array of LEDs that will get your attention.