The phrase "assembled masses" is correct and usable in written English.
It can be used to refer to a group of people who have come together, often in a political or social context.
Example: "The assembled masses gathered in the square to voice their demands for change."
Alternatives: "gathered crowds" or "congregated people".
The assembled masses didn't care.
Calling out the assembled masses for being a bunch of hoity-toity pinkos, though?
It was nearly 5 p.m. before the vehicles crawled through the assembled masses.
When Elder addressed the assembled masses before the concerto, he reminded them of the grand musical heritage.
The set by Fan Yue is dominated by stairs through which you can sometimes glimpse colored banners and assembled masses.
An unusually competent research group has assembled masses of useful material for the 1970 Sen ate races.
IN November 1970, after haranguing an assembled mass of Japanese soldiers about their betrayal of their nation's glory, the writer Yukio Mishima, aided by unflinching friends, committed seppuku, a form of ritual suicide that involves disemboweling, decapitation and an almost unthinkable mixture of discipline, pain and mess.
It was a sober affair, with barely a peep from the assembled mass.
The red carpet got its fair share of expensive shoes, with a cast that includes Steve Carell, Ryan Gosling, Emma Stone, Julianne Moore and Marisa Tomei, walking along and mugging for the assembled mass of photographers.
A team of riot cops appeared, but not before the assembled mass had made their way from the entrance and down to a branch of Starbucks.
The police were showing scant regard for protest etiquette; right after the protest started, they too started beating the shit out of the assembled mass of demonstrators, with riot cops laying into people all around us.
