The binaural interaural crosscorrelation parameters are defined in the Calculate->Spaciousness section.
The time limits t2 for IACC early (early time) and t1 for IACC late (late time) can be changed in the boxes shown in the figure above.
The calculation of IACC is substantially more time consuming than the other parameters, even if it is implemented using a fast frequency domain algorithm. This is especially true for the late and the total versions. If not explicitly needed, these parameters should therefore be excluded from the calculations.