Quite a while back, I had full range speakers and was testing crossovers and the concept of stereo bass for music and discovered that I needed to use crossovers below 80Hz to eliminate localizing the subs. My subs were both on the right side of the room and after testing some scenes that had rumbling that panned through the speakers, I discovered that I could tell whether the crossover was at 80Hz or higher, or 40Hz, based on the directions the bass emanated from.
With the 80Hz crossover, I could hear the higher frequencies of the rumble panning, but the deeper frequencies came from the right side (where my subs were), and the deepest frequencies seemed to be everywhere.
When I lowered the XO to 40Hz, I felt all the bass frequencies panning, except for the deepest frequencies which seemed to have no localizable source. I played these scenes about 90-120 times while switching back and forth and trying different crossovers. I ended up settling on 60Hz.
Note that there's a difference between localizing 80Hz and below, vs localizing subs with an 80Hz crossover. The LPF isn't a brick wall. An 80Hz LPF in the crossover means content at 160Hz is -24db. I don't know if it's possible that I'm picking up some of these lower level but localizable frequencies with the 80Hz XO.
In addition, I'm not sure if I'm localizing by hearing, or feeling. One of the things I noted was that with the lower XO, the panning rumble had a similar sensation to something big (like a semi) passing close by. The higher XO did not create the sensation. I heard the sound pan past, but the bass was coming from the right side.
After I discovered this with the demo, I found that I could locate hidden subs at a club I was in from this same phenomenon. I walked past the overhead speakers and thought, "I don't see the subs", and realized I could feel them. I could feel that the 'thump' was coming from over 'there', and when I went looking in the direction of 'the thump', I found the subs neatly concealed behind screens.