Wayne Parham Messages: 18791 Registered: January 2001
Illuminati (33rd Degree)
The mouth area sets the lowest frequency where pattern control is maintained. A horn that is larger in one dimension than the other loses pattern control on the smaller axis sooner than the larger one. If the mouth area is large enough, pattern control can be maintained throughout the passband of the device. But that takes a very large mouth, and is usually one of the tradeoffs in horn design.