White uses the car’s top–of–the–range stereo system as one of his main monitoring references when judging mixes, having them beamed to him via an FM radio transmitter.
I just read an article where a couple guys were talking about how they did a lot of work on their latest album in cars. I think it was mostly demos and arrangements and things, but there was mention of tracking vocals in a parking lot. The guitarists had to stand outside the car cause the vocalist was self-conscious. IDK if they were actually listening on the car stereo, though. Probably just earbuds. Who was that? Where was that? I'll have to go look...