Upper class men had more options, including coffee houses and later gentlemen's clubs.
By later standards these were formal events: the attendees were usually screened to make sure no one of insufficient rank gained admittance; admission might be subscription only; and unmarried women were chaperoned.
Nonetheless, assemblies played an important part in the marriage market of the day.
On the other hand, in smaller towns a single large room attached to the best inn might serve for the occasional assembly for the local landed gentry.
London also had a number of outdoor "public gardens" where similar entertainments took place.