I could see building it using a digital crossover, like a miniDSP 2x4hd or FLEX, so the crossover could be 4th order and EQ could be added with ease to fix the bass hump and the few bobbles in the midrange and highs.
"Why such a flat enclosure ?" The wide baffle serves to help isolate the front drivers from the rear drivers to reduce some of the peaks and dips in the response when sound from the back leaks around to the front. When playing around with the cabinet depth, I found the shallow cabinet had the flattest response as well. The shallow box leads to the need to offset the woofers as if they are back to back the cabinet must be deeper. It's pretty easy to change the cabinet parameters and watch what happens to the Directivity plot and Frequency response plot. I've spent hours doing that developing the three way bipole I built this year.
I used the 1" tweeter without the waveguide. So that was a change from the example in the software. That tweeter is getting expensive, but it is really good with large Xmax and low distortion. It is available at Solen in Canada, but it is not cheap. If anyone orders these, ask that they are packed with padding. The small box they come in from Visaton is fragile and if dropped in that box the tweeter gets misaligned. The metal dome tweeter from SB Acoustics might also work well in place of the Visaton for half the price. It's not too difficult to overload the SB parameters and response files into the tweeter page of the boxsim software.
I will attach the boxsim file I used. I had to zip it up as the upload won't take a boxsim file directly.
As you mentioned it can be fun to swap the phase on the rear drivers to hear the effect. Depending on the baffle width the low bass will likely drop out 6 dB or more. The other thing to do, as you have mentioned in other posts, is to add delay to the rear drivers to smooth the forward response and get a sort of point source effect rather than the omni pattern.
"Why such a flat enclosure ?" The wide baffle serves to help isolate the front drivers from the rear drivers to reduce some of the peaks and dips in the response when sound from the back leaks around to the front. When playing around with the cabinet depth, I found the shallow cabinet had the flattest response as well. The shallow box leads to the need to offset the woofers as if they are back to back the cabinet must be deeper. It's pretty easy to change the cabinet parameters and watch what happens to the Directivity plot and Frequency response plot. I've spent hours doing that developing the three way bipole I built this year.
I used the 1" tweeter without the waveguide. So that was a change from the example in the software. That tweeter is getting expensive, but it is really good with large Xmax and low distortion. It is available at Solen in Canada, but it is not cheap. If anyone orders these, ask that they are packed with padding. The small box they come in from Visaton is fragile and if dropped in that box the tweeter gets misaligned. The metal dome tweeter from SB Acoustics might also work well in place of the Visaton for half the price. It's not too difficult to overload the SB parameters and response files into the tweeter page of the boxsim software.
I will attach the boxsim file I used. I had to zip it up as the upload won't take a boxsim file directly.
As you mentioned it can be fun to swap the phase on the rear drivers to hear the effect. Depending on the baffle width the low bass will likely drop out 6 dB or more. The other thing to do, as you have mentioned in other posts, is to add delay to the rear drivers to smooth the forward response and get a sort of point source effect rather than the omni pattern.
