[Chrisbee]

I vaguely remember something about heating being a good thing for a sealed box. Since air becomes more rarefied with increasing temperature. It was claimed (decades ago now) that stuffing a sealed box with a particular fluffy material fools the driver into thinking the box is larger. This was due to the frictional heating effect on the stuffing material. I believe the stuffing recommended was long fiber/fibre wool. This is supposed to slightly lower the resonance of the system. If all this is true then a leakage would not be beneficial.

My own fuzzy logic suggests that heating the air causes it to expand. Which would increase the pressure and fool the driver into thinking the box was actually smaller than it is.