@Norb If you really must know, using the specified drivers, a sealed box around 0.325 Cu.Ft. will get you really close to 180Hz. The Q will be ~1.4, not the greatest for SQ. You’d be better off building a bigger box, lowering the Q and then using a crossover – passive or active – to get to the desired F3. Yes, it’d be much smaller, but It would be a serious challenge to get the required volume (that low) with all the driver/horn depth requirements. Plus you’d then need to put them on something to get the tweeter up to ear height.
Just thinking in the practical realm. If you want to join me in my Don Quixote escapades, then by all means go for it. You always learn best by doing. 😁👍