What is the rule of thumb for low cutoff of midrange tractrix horns? I wish for a crossover point of 500Hz, so should I consider what people claim to be 250Hz horns or will 400Hz be sufficient? I have seen advice varying from Fc of one octave to a fraction of an octave. I figure one octave to be the frequency divided by 2.
Also, will the larger horns increase the beaminess of these horns to a noticable extent, given how beamy they are to begin with? Will they have any other non-desirable sonics compared to a smaller horn? thanks.