"There's no reason that corners lead to boomy bass or that out from corners results in smoother response."
Um, this is not true. Placing subs in most any corner arrangement, WILL DEFINITELY (like, every time...) excite all the bass modes in the room, resulting in that boomy unnatural
sound that's most often described. In short, in-accurate distorted bass, that has many over-reinforced response peaks in the sound.
Now, unless your room is very small, and your corner placed subwoofer is then only causing a peaks and dips at only 2 or 3 frequencies, depending, you might find that there's only a bass hump of sorts, in regards to the response curve - in which case certain response attributes of your sub, your seating arrangements, and-or EQ settings (whatever) might not have you noticing too much unnatural sound and uneven response from the sub. However, placing the sub right at 3 room boundaries will, yes, most definitely cause you to have to somehow adress the bass response anomalies, for accurate response - even beyond simply adjusting output/volume levels.
One thing as an advantage (however, absolute phase is still to be considered, if not adressed) to placing subs in the corner, is that you can get more output and efficiency in the corner placement, and todays EQ's can do a superb job of smoothing out the response curve.
Anyway, I don't like the statement that "there's no reason that corner placement results in boomy bass". My experience says that does not compute.
