does tuning drop or rise when subs are in?

[Awaiting_Equinox]

for example, a 16 cubic foot box tuned to 25 hertz before displacement. will it still be 25 hertz even after I drop the subs in? will the tuning rise? or drop? another question, how do I add the displacement of my sub to the cubic feet of the box? lets say my box is 16 cubes and I want to know how much cubes it will be after displacement. I know it will less than 16 after displacement but how do I go about that? the displacement of my sub is 176.6 I don't even know if that's the right number but that's what it says in the owners manual it says 'net displacement 176.6' beginner here, any help is appreciated

[OrionStang]

176.6 what? Inches? Centimeters?

[CleanSierra]

Tuning will raise when you subtract internal volume and no other variables change, like port length.

[alaskanzx5]

What speakers? Link to speakers?

When volume decreases tuning goes up. In your situation I wouldn't imagine tuning going up enough to hear a difference.