How to make radio sound or music sound with navigation voice work at the same time? HD

NOTICE : we just test one navigation on JOYING android 8.0 FYT car stereo, and cannot confirm all maps can work like the above video show. You can have a try, and make comments to us. Here are some steps: 1. connect Internet on the car radio 2. set your favorite map as default navi map 3. turn on GPS Mix stetting 4. Adjust the sound mixing scale and car stereo volume 5. Download the maps voice packet