Originally posted by GrahamN
Steve,
As you may have seen, Merlin (Michael) is a huge supporter of the TACT 2.2 system and, from what I've seen, his views on room acoustics (including strategies for subwoofer integration) come primarily from them (which in not necessarily a bad thing 
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Graham is quite right that my interest in room acoustics was started by researching the Tact product. Not one to take marketing blurb at face value, I have done research to see just how valid some of the theories are, and have also been able to do some practical experiments that appear to back them up.
As a caveat, I work from a slightly different script, as I have to take less account of room effects than you do, that said I still do need to place the speakers in my room optimally, it's just that I can iron out some of the problems that arise from this positioning, and accept less of a compromise.
The first point comes straight from Peter Lyngdorf's thinking, but is backed up by simple physics. Whilst the directionality of sound increases with frequency, it is accepted that bass notes, due to the long waveform, are omnidirectional, radiating at 360 degrees from the transducer. This, in a typical enclosure generates a backwave, which will rebound off the rear wall, potentially invert phase, and then arrive at the listening position.
The first problem is that the sound of the reflection will arrive later than the direct portion of the sound. If your subs are two feet out from the back wall, the reflection will arrive four ms or so after the direct output, having the effect of blurring the LF energy over a period of time (in this case 4ms). In addition, this backwave can, due to it's inverted phase, act to cancel out the direct sound, paricularly at certain frequencies (this dependent on the distances involved. Hence we have uneven, weakened and time smeared bass response.
The answer is to remove the backwave, this is done (in the case of Tact and Nestorovic) by firing the bass units into the rear wall or corners at very close range. This ensures that the back wave arrives at the same time as the direct sound, and that it is in phase with the direct sound over the operating range. This leads to reinforcement rather than cancellation, and to less smearing in the bass. The result is less colouration, and greater transient attack.
It is widely accepted that the interaction of speaker directivity and your listening room is a key factor in getting good results. I believe that controlled directivity, aimed at suppressing the destructive contribution of the listening room, should be a design priority.
Now going back to point 1, we already have, in your setup, a potential delay for the reflected bass soundwave of 4ms. When we then place the satellites three feet in front of the subs, this delay extends to 7ms, quite considerable. And that assumes that the bass units employed are of sufficiently low moving mass to show a similar rise time to the ultra fast Bandors. I can say that, from my subjective experience, this delay will lead to a percieved increase in ambience and body, at the expense of transient snap and timing. That's not to say your speakers don't subjectively sound excellent, just that it may be possible to improve on them.
You may also be interested to know that I find the least compromised position for the satellites is up against the side wall
This again ensures that the first reflection is in time with the main output, and that it's spectral balance is very similar (assuming you have a hard plain wall).
Of course, both of these optimal solutions can lead to problems elsewhere. In particular, corner mounted subwoofers will excite first and second harmonic room modes and cause uneven bass. This is where I advocate equalisation, to cover the lower frequency decade. It is also, as the above indicates, not a bad idea to delay the signal from the satellites sufficiently to ensure that the wavefronts from both them and the subwoofers launch at the same time.
I hope that helps to clarify my position. I might add that, whilst there is plenty of empirical data to support the above, the proof has been in subjective testing carried out over the past nine months.
"Anxious", that's the most succinct single word description I've aptly heard applied to the "Old Skool" Naim sound. Even makes your adrenalin rush with music that's supposed to be relaxing. 
