I came across an AES paper recently (Martens, Braasch, Woszczyk 'Identification and Discrimination of Listener Envelopment Percepts Associated with Multiple Low-Frequency Signals in Multi-Channel Sound Reproduction' that shows the result of a study from which the conclusions were that keeping bass signals separate above 50Hz contributes to perceived envelopment and spaciousness of the sound.
The extension of this conclusion being that for ultimate quality the main LR speakers should NOT be crossed over to subs located physically separate (e.g. in the corner or behind the listener) from the LRs above about 50Hz. Also that the LR signals should NOT be combined monophonically and directed to sub(s) since the signals above 50Hz contain information that contributes to overall sound quality.
What are people's thoughts on this? How does this fit with the typical paradigm of combining musical information monophonically below about 80-100Hz? How does this work with the Geddes multi-sub approach for music?