The question is always one of audibility, the ragged off-axis off the ATCs is immediately obvious when compared to a really transparent design, my process here for the last fifteen years or so has been to try and hear and compare everything here in my rooms and then try to draw some correlation between the sound of the loudspeakers and their measurements ( if they are available).
) I have found the more identical the on and off axis the more transparent the loudspeaker sounds, a speaker with a cardioid response not only measures more tidily but is clearer.
I could never really see the point of representing ‘second-best’ and that has led to a relatively small selection of designs which I use as my reference.
There is an interesting thread where this topic ( controlled directivity in low/mid bass) is being discussed at this very moment.
Allow me to elaborate/clarify … I am referring to the listener/customer that does not have a dedicated listening room, rather it is a normal listening space, and does not have the need to get that last small percentage of improvement that treatment would provide with a properly designed speaker...
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Keith