I have a 10'x10' room in my garage that I use as a drum set practice room. I've been sealing it up better to provide some sound proofing. The sealing is not extreme, but I have an exterior door (like a front door) with no blatant air gaps, and there are no vents into the room. I don't want normal vents because the sound will pour out. There is also a normal, but quality window.
My question is whether I need be concerned about the lack of ventilation if the longest I'll ever be in there is 2-3 hours without opening the door. I'm not asking about building code, but whether a person could actually use up too much oxygen relative to what will seep in through the gaps in the windows and doors?
I know I can make a project out of building a muffled ventilation path, but want to avoid that work if not really necessary.