InterChannel Phase Alignment (IPCA)
Since Acourate 2.0, Uli has introduce a filter to compensate for the asymmetrical room setup and make the step response in both channels a closer match. More information here https://www.audiovero.de/acourateforum/viewtopic.php?f=8&t=171
The aim of ICPA (InterChannel Phase Alignment) is to align the group delay behavior in the important frequency range up to 350 Hz. This has a positive effect on interference between loudspeakers. The cause of phase differences is usually given by asymmetries in the room, in the speaker placement and in the furniture. Eliminating them by rearranging the room is often undesirable. Acourate offers the solution for this with ICPA.
To show you the results of this filter, here is the step response before the implementation of ICPA
This is after
One can see a much tighter match between channels. And here is the Step response with an ideal step response