I 've been calculating a 4th order bass reflex cabinet at 10,1cft using Vb=(15)(Vas)(Qt2.87)

Then found F3 32,5Hz using F3=0.26(Fs)/(Qt1.4)

And Fb 27,3Hz (basically the port tuning) with Fb = 0.42(Fs)/Qt 0.9

What if I increased cabinet size to 12cft?
How lower will F3 be? Any drawback?

I want to build two cabinets to use up to 800Hz for home duty. No PA action here.