Dragging midi notes no longer makes any sound

When using the piano roll I like to hear the midi notes play as I drag them up and down the scale. Today when I was working I must have hit something, because now sound no longer plays when I drag notes around. I can’t seem to find how to change this setting back to its default. Does anyone know where this setting is located?

I think this is the Acoustic Feedback button. Can’t remember what it looks like. Maybe an " A" or a speaker on it?

Edit: Just checked. It is a speaker. P. 685 in the manual.