Here's proof from one of my classes last year:
The first video is of students debating for one minute on simple topics like "tea is better than coffee" and "watching news on tv is better than reading a newspaper." I tell them "outside yes, inside no" and then they have to support the opinion I've given them. Since they only have one minute to discuss the topic, they get really loud really fast. I love it.
The second video is of an activity I'm going to do in class tomorrow. Each student has a partner--one sits down with a pen and paper, the other runs back and forth from one side to the other. Why? Well, they look at song lyrics, memorize a line or two, and then run to dictate that line to their partner. First pair to finish wins.
Of course not all of the activities we do are this noisy . . . but I do love it when my classroom is so loud I can't think.