Stacked "Endfire" Subarray?

Hello there,

I’m trying to wrap my head around a sub configuration I think I’ve seen used with L-Acoustics rigs, but I’m not sure if my theory holds up.

The setup:
Two subs stacked, one facing forward and one facing backward.

The processing:
Instead of the standard Cardioid approach where you delay and flip the polarity of the rear sub, this method involves:

- Delaying the forward-facing sub to physically align it with the rear sub.

- Adding an additional quarter-wavelength delay to that same forward sub.

The idea is to create an endfire-like pattern. Theoretically, this should push more energy to the front compared to a standard cardioid flip, and losing a bit of rear cancellation.

My questions:

• Does this specific "forward-delay" method actually yield more SPL in front?
• Are there hidden phase issues or frequency response lobing I'm overlooking?
• Should I just stick to a regular cardioid setup?

I’d love to hear what you guys have to say!
Thanks!