My tiny little radio speaker directed to the seat was really too difficult to hear. So I came up with this solution. Recipe below
Fat Full Audio
Add one part 3.5 TRRS screw tap adapter.
A dash of short patch cable
and poof Audio going through the Car Radio.
This is what I have undertaken for a winter project. We picked this scanner up for 12$ on ebay to house all the components I intend on using. The internals will be scooped out and I'll 3D print a new cradle to hold a Raspberry PI and an RTL-SDR dongle(See last picture for that). I'll also have to cannibalize a set of PC speakers for the amp for the audio. More to come on this project.
Got this new radio and found there was little to no information on the pin assignments. I found this which was flipped. I had given up until almost midnight I thought what if this guys diagram is backwards. So I tested 4 for ground and there wasn't. Then I tested 3 for ground and there was. So I touched 3 and 1 together and click it was transmitting. So a quick wiring job with a RJ11 and a couple of keystones and boom it was working.