When calculating port parameters, is the volume of the port subtracted from the calculated size, or is it usually compensated for in the design? For instance, in a particular 3.5 cu.ft. design I'm working on, the optimum port size to avoid turbulance works out to .75 cu.ft. port displacement volume in this case. Does the 3.5 cu.ft. size usually take that into account, or should the cabinet size be increased to 4.25 cu.ft. for the same performance? The programs I'm using are not really clear on this point.

It seems like it should already be compensated for, or else you'd constantly have to recalculate values to get a final refinement. It's just that .75 cu.ft. is a pretty big chunk of displacement out of 3.5 cu.ft., so I'm a little concerned...

Thanks for any info - John.