If you've been reading Harman papers then you should know that high resolution measurements (REW = 1/24 octave, although 1/16 is probably sufficient) across the listening positions as well as defining a grid across the room with measurements, as well as performing the axial mode calculations will guide you to find the best possible woofer positions.
Remember, below 200 hz, the room is in control. No super sub is going to change that, so you have to deal with it. 'Tight' and 'fast' are descriptions of the time domain, and often the failure of a sub being located in a position where multiple height/width/length mode resonances stack up.
Many people have been jumping on the miniDSP bandwagon, for the wrong reasons. Incomplete measurements lead to applying filters below the resonance frequency of the woofer, and blind boosting of low frequencies which result in the degradation of bass quality. Sure you'll hear more boom, but it will not sound accurate. With the correct measurements, miniDSP allows you to counter resonances when placement options are exhausted. You match the measured peak in frequency, amplitude, and bandwidth (Q, in this instance) and create a filter with to lower the amplitude of a resonance, or, boost a null.
And thats the short version.... it's a lot of work, but it's the only way to do it right!
