HELP calculation impedance

Hello the forum.
I have a data sheet that gives me the values of the impedance of a loudspeaker from 20 Hz to 20 kHz.
The measurements are made at 0.280 V, in free air (DAYTON / txt .zma file).
My question:
How to convert these impedance values for the loudspeaker in closed enclosure of defined volume Vb?

Thanks for your help.
 
Last edited: