"Je ne sais quoi", perhaps? https://en.wiktionary.org/wiki/je_ne_sais_quoi
"Je ne sais quoi" means "I don't know what"; "Je ne sais pas" just means "I don't know".
I agree with you. There's something about the aesthetics of AM radio that favors talk radio. In a former life, I would listen to a lot of political talk radio (from a few major brands), and switching over to listen to them in FM just wasn't the same. I preferred listening on AM.
There's also something about the sound of AM that is somehow nostalgic and reminds me of taking long road trips cross-country in lowly populated west or mid-west states with my grandparents. The "reach" of an AM station somehow connects with me and the impression on me will unfortunately die with my generation; at least, I know my kids have no consideration for AM radio, or radio at all for that matter.
1. Signal strength is much more consistent and further reaching.
2. I don't have to worry about my wife changing the station on the AM radio in the car. The FM radio could be set anywhere, but when I'm driving I just change it to AM and there's my station.
3. There's a "je ne sais pas" factor in the fuzziness and softness of the audio that I find pleasant and less harsh than what you get with talk radio on FM. Maybe for the same reason people like the sound of vinyl records, though I'm not into vinyl.