In the 80's when I owned a record store near Savannah, there was one album I could play and guarantee someone would buy a copy everytime. In fact, before putting it on, I would always go over to the bins and make sure I had at least 2 or 3 copies in stock. This album was jazz fusion and was a double record and listed for $15.98, hefty price at the time.
It was Pat Metheny Travels, a 1983 release recorded live on tour in 1982. I had a killer sound system in the store that was 20' wide and 80' deep with a huge speakers in each corner. To make the sound reach and blend in the center of the store I had to turn it fairly loud. Everytime I put this record on, at least a half dozen people would ask, who is that? As I said, 2 or 3 would buy a copy. I would call this mood music, whatever mood you were in, your mind would be taken somewhere else.