Loud droning noise from 2023 iMac

The next time if starts "droning" open Activity Monitor and see what's taking up the most CPU resources. That can tell you which app and process is causing the fans to run up.

The fans in Macs:

— run all the time

— speed up when needed. They are controlled thermostatically— "on demand." Sensors arrayed around the interior check for increasing temperatures caused by heavier workloads, and tell the fans to speed up.

Heavy workloads that WILL make the fans speed up are:

— gaming

— watching videos

— videoconferencing

— video editing

— code compiling

Browsers can be brutal. Chrome is a notorious resource hog. Even with kinder, gentler browsers, some web pages will create more work than others. Video ads don't help.

Your iMac 2024 has two fans, one at either end of the logic board about 4.5 inches inboard from each lower corner. Be sure not to blcok the a\air intale area between the bottom edge of the case and the work surface.

Droning, usually indicates the fans are working, because the CPU is getting hot, and needs to be cooled. Perfectly normal if you are using the Mac and it's requiring a lot of processing power.