first time I thought I showed up to a disco and not a race track was around 1990 at Limaland, I not positive on the year but Sarah Fisher was driving the Mead #9. Anyhow, they didn't announce much of anything, just music blaring constantly between races. It was a Ohio Sprint Speedweek race though and was so dusty you couldn't see most of the action.
When I announced out in California in the 70s, I had some music to play, but only used it when they were working the track before qualifying and before the features.