I have 4 subs with an SMS-1 processor and I would totally agree location and acoustics are the most important elements in getting the smoothest bass response. I would, however, submit that the SPL meter drops off significantly in accuracy below 50hz so you won't get an accurate reading of that REAL DEEP bass. This was confirmed in Ian Colquhoun's tutorial on the subject plus a number of other manuals. The advantage of the SMS-1 in this particular case, to my hearing anyway, is it enables you to pump up that deep bass(provided your subs can handle it) and in turn, turn the overall volume down slightly to compensate. Although sirquack's graph is showing generally a balanced response, especially with room treatments applied, the deepest bass(25-40hz) will be masked by the upper bass frequencies since the ear still can't hear these lowest of frequencies as well especially at lower volumes. A similar principle was applied to receivers in the recent past that had a "loudness" control. This is strictly my opinion and in the end, it's all about personal preference anyway.
