So let me get this right. Rather than a lead-filled Durex, if I think of the volume of air shifted as being like a cylinder of something, like, say, cake, I'd get just as good a low frequency using multiple Mr Kipling Mini Apple Pies as I would with a large Black Forest Gateau(x).
And being that 6 Mr Kiplings are cheaper than one Gateau(x), the low frequency will be cheaper but taste just as nice.
OTOH, given the ratio of cake height to radius (which is approximately constant between the Pie and the Gateau[x]) what would happen, theoretically, if I had a cylinder with a smaller surface area (cake top) but greater 'excursion' (cake height) - e.g something like Tesco's Value chocolate sponge roll.
Eh? Eh?