Ok, so I was setting up on a show last night - and the system tech had the subs done in a way I've never come across before.

We were running with a JBL Vertec line array, and he had six of the Vertec sub cabinets placed under the front edge of the stage - 3 in a line spaced evenly along the front, then 3 more placed evenly behind them.
The net result was really interesting - with a 50Hz tone through them, they sounded huge in front, but once you moved around the side of the stage - the bass dropped off, and then dropped off significantly more again round the back. There did appear to be some form of Lobe as you got parallel with them along the sides of the stage though.

Unfortunately, I couldn't get to have a look at what he was doing with the system processing, but I'm making the assumption the front row was time aligned to the back row, coupling them in front, while cancelling certain frequencies at the rear depending on the spacing between the 2 rows.

Definitely made working backstage easier, and FOH was still punchy and great.

Anyone else come across this? I'm keen to look into it more and use the idea on future gigs, but don't really know enough on the method yet.