I obtained a very nice used Tesseract audio mixer/amp and installed it on my BMW F800 yesterday.
It allows me to plug my GPS and V1 radar detector into its inputs and a set of noise-suppressing in-ear monitors into its output and hear GPS voice directions, MP3s (which I don't do while riding), my phone (ditto), and the V1.
It has a noise gate on the V1 input so that circuit is totally silent (no RF or "white" noise or static) until the V1 breaks the squelch with a radar alert.
Poking out of the faux tank just where it meets the front edge of the seat is a female jack into which I insert my Etymotic ER6i earphones, meaning the cord is down low under my jacket and not whipping around in the wind.
The V1 easily overpowers the GPS spoken directions on the occasions when they overlap and all muting and volume functions work OK with the Remote Audio adapter.
My only tiny beef is that the noise gate is not adjustable. It would be nice to get it to accept a slightly lower volume level from the V1 to open the noise gate.
Here's a pic.