Sealing ported box

[white4d96]

I built a ported box some time ago and am using it for my Type R 12's. Unfortunately I didn't calculate port area properly, as such my port area is WAY too small (about 10 sq inches per actual cube, and with the polyfill, 7 sq inches per cube). I am in the process of designing a new box but in the meantime, can I glue and screw a piece of MDF over the tube ports to seal the box? I'm sick of port noise.