Asymmetric radiation in upward and downward directions supported by leaky modes can be generally exhibited in the reciprocal but geometrical up-down mirror-symmetry-breaking structures. i. e. photonic crystal slabs. https://www.diegojavierfares.com/amazing-price-Kicker-48CDF104-Comp-10-Down-Firing-Loaded-Subwoofer-Enclosure-special-find/