Asking Differently - Setting Sub Delay

[Delija]

As already said, it's not enough just to measure the distance - the DSP in subwoofer(s) adds some delay.
The best way is to experiment and measure (REW, XTZ Room Analyzer...) the frequency response - to achieve the best integration in the crossover area.
E.g., for SVS subwoofers (in my case dual SB16-Ultra) I need to add additional 2 ms to compensate the DSP.