Spherical speaker enclosure - Calculations for Bass-Reflex enclosure and Internal Helmholtz absorber

Hi, I'm looking for somebody to calculate the parameters for the design of a spherical speaker enclosure shape to be manufactured in high-tech concrete. We're using a 5" driver : Tang Band W5 2143 (complete specs below and spec sheet available for download). - Calculate correct internal volume for Bass-reflex operation (Bessel alignment with FB of 45.7 Hz) - Recommendation for placement and number of Bass-reflex ports to avoid port resonance the most possible. - Calculate correct dimensions of a Internal Helmholtz absorber to lower the enclosures internal resonance. - As a plus It might be interesting to to look into modelling the enclosure in COMSOL or other FEA application to be able to reduce resonances even further. Thiele/Small parameters of W5 2143 driver below : ------------------------------------------------------------ Resonant Frequency (Fs)55 Hz DC Resistance (Re)6.3 ohms Voice Coil Inductance (Le)0.023 mH Mechanical Q (Qms)3.21 Electromagnetic Q (Qes)0.43 Total Q (Qts)0.38 Compliance Equivalent Volume (Vas)0.671 ft.³ Mechanical Compliance of Suspension (Cms)1.398 mm/N BL Product (BL)5.43 Tm Diaphragm Mass Inc. Airload (Mms)5.99g Maximum Linear Excursion (Xmax)2.5 mm Surface Area of Cone (Sd)97.83 cm²