There has been some discussion regarding the "cardoid" subs that were present and some confusion on the terms. Like with full range boxes terms can have different meanings to different people.
Take the term Active. In days of old when you were discussing active vs passive loudspeakers you were talking about whether or not the cabinet had a passive crossover in it. The active part was the electronic crossover before the amplifiers.
Today active can still mean that, or it can mean that there is an amplifier built into it. It is just how you look at it.
In regards to cardoid subs, there were several in attendance. It all depends on how you define "cardoid". The only "active" cardoid (using other loudspeakers to cancel out rear radiation) was the EONA 618. It would have been good to have the Meyers there, but for some reason they weren't. Maybe next time.
The EONAs did a very good job of knocking down the rear radiation. Was it completely gone, no, but the reduction in level was significant, and I would not expect it to be completely gone. In audio it is all a matter of how much. Just like horn cutoffs, teh sound is not gone, just a good bit lowerer, and some cabinets have a harder cutoff than others.
One of the other "passive" cardiod subs (in my opinion) was the Tripp. When walking behind them, the level was quite a bit lower than in front. Was it as much as the EONA, I am not sure (as the Tripp came first), but I would say they were in the same ballpark. The time between listening was a fair bit, so your ears tend to forget very quickly. We were also in a small room, which will greatly affect what what you hear bouncing around.
No measurements of this were taken, as it would probably be futile in the room we were in to try to get an decent data of that type. That is best reserved for outdoor measurement.
There were some cabinets in which the rear radiation was just about equal to the front and others had various degress of cancellation to the rear.
Just like with a cardoid mic, You have your "basic" models in which the ports on the rear of the capsule cancel out the front and you get a cardoid pattern, you can take an omni mic and put it on a boundary and it will also have rear rejection. How much depends on several factors.
I think the term Cardoid generally refers to active cancellation type subs, but just wanted to point out that there are others that do a good job of it without the added loudspeakers in the rear. Are they better or worse, I don't know, just different.
There are also various configurations in which you use delay, polarity and physical placing of the cabinets in order to achieve this effect. This starts to be a large (physically) array, but can be effective if you have the space, the number of cabinets and the knowledge in order to make it work properly.
And with ANY of the above mentioned methods, it is all frequency dependant. While the truly passive (no electronics) subs will generally have a linear pattern control (as you go higher, you get more rejections) both of the active (built in or DSP based) methods are good only over a particular bandwidth. Out side of that (high and low) you will have less control over the pattern.
So the real trick is to only have the cabients freq response centered over where the greatest cardoid action is happening or vice versa, determine the freq band if interest and adjust the cardoid action to be centered over this range.