Anyone heard of the B-52 COMP-4CLS?

the SPL matter is based on how the driver and the horn work together.
The acoustic impedance matching between the two determines the
:)shhh: I'm a newbie too in these things)
Since you decide the crossover point, you can easily calculate the lower
cutoff point that is determined by the size of the horn, precisely by the
measure of its mouth : just divide the velocity of sound in air ( 344 m/s)
by the lenght of the for 2KHz you need about 6 " mouth aperture.
I suggest to try elliptical mouth horns.