My experience has been that the. larger and more full range the speakers, the more that system benefits from more Mana. For instance I used to have a second system to play with which consisted of a Naim Nait2 and Royd Edens (LS35a/Kan size}. That system just clicked at phase 2 Mana, with the Kan stands, which supported the Edens, on a soundbase each. More levels for that setup over egged the pudding and IMO tried to squeeze too much bass out of the Edens, which stressed both the amp and the little drive unit.
This would suggest to me that Mana works largely at bass frequencies, you know how when you clean up the bass, the mid and top sound clearer too, with each level cleaning up the bass a degree more than the level below. The more bass capability a speaker has. the more it benefits from large stacks of Mana, which may go some way to explain why so many of the very large rigs use Linn Isobariks. Love em or hate em, I don't think anyone would deny that those Briks have serious bass.
My own system of compact Dynaudios driven by a Densen DM10 seems to optimise nicely at around phase 4, or so, any more seems to put a bit more work on the Densen than I feel it really likes. Thus those of us with smaller rooms and speakers can have great sound and spend less money on kit. A very wise man once told me that clean deep bass costs a fortune. By the time you have forked out on the large speakers required, the powerful electronics required to drive them, the levels of Mana to keep things clean and finally the large structurally sound room required to sustain all this he wasn't wrong.
