Have been using REW to attempt to get a time delay / phase correction for sub-woofer. Both mains and sub-woofer are active with inbuilt DSPs (with their own delays) so pure physical alignment of speakers isn't sufficient.
The underlying challenge is that the limited frequency response of the sub-woofer stops it reproducing the timing reference signal for REW. According to other posts I have searched it should still attempt to estimate the delay, but warn that it may not be accurate. I ca