Many times, the issue is not with the gear but with the file format and the resolution of those files.

Most music on iPods is in MP3 format. People don't think twice about downloading or converting to 128kbs...and it sounds halfway decent on the cheap ear buds.... but when they play it back on a better system, the low sample rate shows. It's better to use 320kbs but waves are even better. Many mp3 players will not load waves.

I would suspect the sample rate to be a large part of the problem. I've played mp3's over a PA system and the low quality of the mp3 was very evident...and that was 320kbs.

No matter of you use a radio gizmo or a cable, the results will likely be the same. Radio will probably be worse.

How does a CD of that same song sound in the car? Assuming you have the disk and a player.

You can find my music at:
www.herbhartley.com
Add nothing that adds nothing to the music.
You can make excuses or you can make progress but not both.

The magic you are looking for is in the work you are avoiding.