I always make sure that the air temp in my listening room is set between 21.5 and 23 Dec to ensure optiumum density, but it occurred to me this moirning when "rediscovering" the M2 tat the air is different in my new house, in that it comprises different molecules from my old place. Some may have been transferred in boxes, and on clothing etc, but can't have been much. Maybe I won't be in such a rush to change my DAC after all.