This chart allows you to set voice levels in the classroom. There are three levels: 0 for quiet, 1 for whisper, and 2 for talk. You could have a voice level 3 as well though, and tell the kids that since it's off the chart, that means they can be as loud as they want (for outside play or other times when volume isn't an issue).
Indoor Voice Level Chart
by Brandon Flatt
is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License