There's a
new video with Todd Welti on the Audioholics youtube channel. It covers topics including stereo bass. Its main purpose is to discuss a new Denon and Marantz feature that allows "directional bass", which extends the stereo bass idea to multi-channel.
Although they don't mention it specifically, it made me recognize certain rhetorical aspects of the online discussions regarding stereo bass. This feature is presented implicitly as something that confers only benefits, as if there were no downside whatsoever. There is a downside though. With stereo bass, you give up on modal control (which requires mono bass). Modal control is essential to reduce seat-to-seat response variation, which can become extreme.
Edit: One might make the argument that if you're only concerned with a single seat, there's no advantage to mono bass. But consider a single listening position, the MLP, using two subs. Let's say one of those subs gives a response suckout the MLP at some frequency, while the other has a strong response at that frequency at the MLP. When combined, one sub "fills in the gaps" of the other at the MLP, giving a moderate response dip and making the summation much easier to equalize. But for this summation to work properly, mono bass is required, so this argument breaks down as well. The advantages of mono bass are not limited to the multiple listening position scenario.
One amusing part of the video occurs when Matthew Poes describes some discussions he had about stereo bass with David Griesinger. Apparently, David had Matthew set up multiple subs in his bathroom in an attempt to demonstrate some aspect of stereo bass. I got a kick out of that.