A lot of the challenge is that while there is no stereo bass in the bottom octave or two, it does sound as if it is stereo. The drum whacks in Bird on a Wire, each one has a definite location. The hall ambience and cannon on Tchaikovsky 1812 are all incredibly precise. When people think of mono they think of Beatle's and other mono records where the sound all seems to be coming from a sphere in between the speakers. That is NOT what we are talking about! This bass does not sound as if it is mono. Not at all.
However, rest assured, it most certainly IS mono! Anyone harboring any doubt whatsoever is welcome to come and hear, I am happy to demo, and you will hear absolutely zero difference when my DBA is run mono vs stereo. Zero. Nada. Zip. None. Because it is all mono!
This actually even makes sense, because when you think about it, how else could it be? The wavelength of these low frequencies are so long, that in order to be picked up as stereo the microphones would have to be located a hundred feet or more apart. Even then, our hearing simply is not sensitive to timing at this degree of precision at this low a frequency. We don't even hear less than a full wave! Don't even hear it!
This is where I think a lot of this comes from. Everyone is familiar with midrange and treble. Everyone knows the importance of phase, timing, etc. This is all goes right out the window with low bass.
Also by the way with ultra-sonics. Super-tweeters, 40kHz, 60kHz, we cannot even hear. Yet they affect the sound in such a big way it changes our perception of even low bass!
The mind is a strange and endlessly fascinating thing. Hearing is not just mechanical. We like to use a microphone as a metaphor for how we hear. But that is not all there is to it. The phenomenon of hearing is far more complex. The mind plays a vital role. Try and get your mind around it.
