Wayne Parham Messages: 18756 Registered: January 2001
Illuminati (33rd Degree)
Directivity Index is abbreviated DI. There is a pretty good explanation of it in Chapter 3 of the JBL Sound System Design Reference Manual. DI matching is a design philosophy that seeks to crossover between subsystems where directivity matches. If this isn't done then the off-axis response is poor and the reverberent field is non-uniform.