On the other hand, a folded basshorn used to 400Hz is not a good idea. Middle "C" on a piano is 260Hz. Think of that. You have most of the fundamental range of voices going through all that wood in the passageways of a Klipschorn. That's what makes voices sound kind of resonant in a Klipschorn. The panels become a sounding board, making voices sound unnatural.

This and other things have been improved using the π cornerhorn design:

• Woofer is acoustically closer to midrange for better integration
  
• Midhorn is larger and allows lower crossover
  
• Midhorn covers the entire vocal range
  
• Midhorn/tweeter crossover is optimized for better summing
  
• All horns provide constant directivity of 90°
  
• Crossover is optimized to maintain constant directivity through crossover regions
  
• Reverberent field is more uniform because of constant directivity