Wayne Parham Messages: 18756 Registered: January 2001
Illuminati (33rd Degree)
DI is Directivity Index. A circular radiator is nearly omnidirectional at low frequencies but as frequencies rise, the patterns starts becoming more and more directional. If the speaker crossover is set at the frequency where the midwoofer's collapsing directivity matches the pattern of the HF horn, then there are no abrupt changes in directivity. This makes the reverberent field more tonally balanced, and the speaker is more natural sounding.