Would a U-shaped baffle with the leg length chosen for 1/4 wavelength also exhibit a cardioid pattern or at least a dipole pattern with reduced rear projection?

In any case, it looks like progressive cancellation at low frequencies is going to nix the use of open-baffle types for DJ use where weight and bulk are important considerations. I might try some in my sunroom where room modes are a problem and high SPL not necessary.

John