Bass response is one of the craziest things in hifi. Over the years and living in different houses with varying room sizes and volumes I would stubbornly set up my stereo with the same separation distance between the speakers and distance from the front wall. I would notice that the bass would often sound better in the back of the room than in my listening chair. The real head scratcher was when I had great bass while standing and it would all disappear when I sat down. Finally, in desperation I moved my speakers closer together and Bam! I had bass again.
The bass response relative to speaker position seems to be a function of bass driver size, room shape and volume. If the drivers are too far apart the nodes rise upward and outward. That is the part I did not visualize- the 3 dimensionality of the bass response until I hit on it. The good thing is, or what I found is that the bass remains the same when moving the speakers closer and closer together once at the sweet spot. So it is possible to attain the largest soundstage possible and have great bass by just finding that sweet spot for the bass. 1 inch or less movement of the speakers makes a difference.
