When using ports that use a wall for one or more sides its common practice to subtract 1/2 the width from the length.In your case this would be 1.5".
Ether way I doubt there will be a noticeable difference if your off by an inch or two.
It probably wont be more the .5hz.
Ether way I doubt there will be a noticeable difference if your off by an inch or two.
It probably wont be more the .5hz.