Cardomon SB - DIY passive Cardioid with extremely linear frequency and Power Response

[nc535]

As you see fit, but if you open the link pasted above and hover your cursor over the -6dB line (separating coral red from orangeish colors, see scale) between 200 and 1000 Hz, you'll see the displayed digit oscillating between 70 and 80° (resp. -70 and -80 on the opposite side), which lands you in 150° coverage territory, more or less...

but recall that my original post had a "<" in front of the 90 degrees. so a figure of merit is how much better it does than that. and it doesn't get much better than D&D 8C.
the real figures of merit for cardioid isn't the H beamwidth so much as how much rejection it gets to the rear and to the sides

 

[Fledermaus]

it doesn't get much better than D&D 8C.
the real figures of merit for cardioid isn't the H beamwidth so much as how much rejection it gets to the rear and to the sides

Right, 8c is about the best you can get with an 8" midwoofer in such an enclosure ; I guess you'd have to add some serious waveguide in front in order to have a narrower beamwidth.
BTW, as I see it, rather than being independant figures of merit, H beamwidth and rejection to the sides have some cause and effect relationship in that kind of speaker.

 

[nc535]

I don't think H beamwidth and rejection to the sides are independent either. I'm guilty of speaking loosely again. Instead of rejection to the sides (or back), I should have said maximum depth of rection, as one would see in a horizontal line chart, I don't think there is a cause and effect relationship between the two, although there may be some correlation. But the maximum depth of rejection is a result of how well you fine tune everything that contributes to it, in particular with the size and placement of the slots and the amount and kind of absorber behind them but also affected by cabinet size and edge shape.