cardioid design

How is cardioid radiation pattern achieved when building a loudspeaker? Are there different ways to implement it and how it works? If someone has already created a thread about this, could you share the link so I can find out? I've searched but haven't found it. Out of pure curiosity. I like to...

Disclaimer#1: Klippel measurements from us (the manufacturer), not independent measurements. Disclaimer#2: Cleared with moderators that it would be okay to post this thread for specific discussion around the measurements and technical aspect of the speakers. For discussions related more...

Hi ASR, it's been almost 2 years since I first heard about cardioid speaker design being implemented in mass-production (it was during D&D ad campaign I guess). Last year I had a chance of listening to 8c and KH310 (w. 750 sub) side by side along with some Amphions, and while I disliked the"out...