So my question deals with open-open tubes. When there is a displacement antinode there is a pressure node. I can somewhat conceptualize this because of the boundary condition where the pressure at the ends needs to be atmospheric. But I am confused about the ideal gas laws relation to this. If a maximum displacement is at a compression of the air, then wont pressure increase since PV=nRT, PM/RT=ρ. At a compression, does the density of particles not increase? Wouldn't this result in an increase in pressure? I can't find anything answering this specifically.