Disagreement alert!
When my Velodyne was in my front right corner, it couldn't get much output below 30Hz. With it in my rear left corner, almost beside my rear couch, I can hear into the mid 20s.
Well naturally if one has an in-room suck-out at 30Hz when the subwoofer is placed in the front corner, then that would not be the best place to put the subwoofer. If I could see your room layout, I could tell you right away what would be good placement options for the true subwoofer.
Nearfield placement of a true subwoofer, especially nearfield placement in a corner, often works great. We've been recommending this for years now for the benefits that it can provide in many systems, and tons of people have been really happy placing the subwoofer in the nearfield. However, this tends to work best in rooms that are relatively deep. In rooms that are not very deep (which represents many if not most typical family rooms), there can be some cancellation as one pressure wave moves forward and reflects backwards as a second pressure wave moves forward. This leads to a dip in the frequency response. Using a nearfield mid-bass/farfield low-bass system eliminates this problem.
I also think this statement is broad generalization because not all rooms are alike, and proper bass can come from many different locations. A flat subwoofer with proper placement coupled with proper room acoustics will not need an MBM-12.
There is no such thing as "proper" room acoustics when speaking about typical family and living rooms. Room acoustics can wreck havok on bass quality. One of the nice things about nearfield placement is that room reflections are reduced, which tends to provide a flatter frequency response over this range. In fact, if you look at many of the frequency response charts floating out there on the internet forums, many people tend to have very rough frequency response in the mid/upper bass range when using their deep bass subwoofer to handle low/mid/upper bass, even though the deep bass subwoofer has a flat or fairly flat anechoic response.
Note that having a flat anechoic response in a true subwoofer doesn't do anything to take away the primary benefits of MBM. The VTF-3 HO Turbo has an amazingly flat response, and yet the addition of an MBM-12 takes system performance to a much higher level. MBM-12 is able to maintain a flat response at much higher SPL levels in the mid-bass, at least 10db higher. Deep bass performance is improved as well when using the MBM, since the true deep bass subwoofer is relieved of mid-bass duties. Intermodulation distortion is vastly reduced since the mid-bass frequencies are no longer modulated by the deep bass frequencies. The end result is much higher headroom, wider dynamic range, and lower distortion that no amount of bass traps can provide or emulate.
