Great e-book. I’m interested in set-up for a single listening position for stereo music. My reading of the e-book suggest that the recommendation for this situation is that a) sub-woofers are most often needed to get full range reproduction and b) just two subwoofers are needed (as we’re just optimising one location). All this makes sense. The interesting part is the recommendation in the section on signal processing to high-pass the main speakers at 80Hz to avoid “unpredictable behaviour”. Is this a reference to the L / R signals vs. the mono signal of the sub-woofers? And, if so, then is there something clever that those of us with JRiver can do via high-pass the main speakers and then adding back a <80Hz mono signal to both stereo speakers?