Speaker systems and the 20 second clock

Quick Question. I am at the Edmonton game right now and the Announcer is still talking well into the twenty second clock and they are also playing music well into it nis it legAl to do this or not?

It's supposed to be. But when the visiting teams crowd is showing up the home team crowd you gotta do something right?

I agree that once the 20 second clock starts, there should be no artificial noise....

however, I think that the rule is that the noise has to stop only once the team on offense leaves the huddle. Is that right?

I think you are right. We kept track a bit more and the esks were even doing it to themselves and stopping o ce they broke the huddle. Seems odd though. I would have expected it to be once the clock started.