Googling to see what I could find, this came up. Apparently the rapt attention style of attending concerts was not always the standard. The description sounds more like how people go see a rock band in a club today.
https://www.newyorker.com/magazine/2...why-so-serious
While most were in their places by the end of the first act, the continuous movement and low din of conversation never really stopped. Lackeys and young bachelors milled about in the crowded and often boisterous parterre, the floor-level pit to which only men were admitted. Princes of the blood and dukes visited among themselves in the highly visible first-row boxes. Worldly abbés chatted happily with ladies in jewels on the second level, occasionally earning indecent shouts from the parterre when their conversation turned too cordial. And lovers sought the dim heights of the third balcony—the paradise—away from the probing lorgnettes.