The Devil said:
Yet you feel qualified to comment on Active 50s, etc. Oh well.
I know the drivers intimately though and this means how they should and shouldn't be used as well as what's optimum for them. Facts is facts, loudspeaker design is loudspeaker design and physics wasn't bent by ATC's implementation to miraculously avoid these problems.
I've also tried ATC's XO implementation... and passed.
I have lived with active 100s for four years. They exhibit no audible distortion. Three of my chums have bought active ATCs after hearing mine: 50s, 100s, and 150s. I've heard all three systems at length, the 50s in two different rooms. None of them exhibits audible distortion, and they all sound superb.
I've also had a shop demo of both active 50s, and 100s. They sounded mediocre, because of a poor source & setup, but there was no audible distortion. I bought my ATCs from an acquaintance who recommended them strongly, not because David Gilmour uses them. David Gilmour does use them, however, which is pretty remarkable given that he could afford any speakers he wished.
Nothing remarkable about it at all. He made a choice and that's it, its not recommendation or confimation that the speakers are 'remarkable'. We've already seen that the DEQX which I think sounds brilliant and measures close to perfect is said to be lacking, clearly there's elements of personal taste, setup and partenering equipment here the same goes for any choice made on equipment. One thing that can't be arguing against is measurements and data that confirm a speaker to be coloured, whether you like that or not is another matter or indeed if you even realise that what your listening is coloured but quoting big names users doesn't invalidate the measured results, which you seem to be trying to do.
The original program material should be as closely follow as possible, adding flavour(intended or not) may sound nice but its ultimately obvious and isn't in the ideal of what I consider an accurate system. The more accurate the system the more heavily you start to rely on good source material and when its good you realise that a system can simply sound real rather than an involving facsimile that some folks term 'musical'.
There's more to be had from the ATC drivers used in the SCM50, that's all I said. Nothing about ATC making poor speakers, why can't you just accept that?
So please don't try telling me that ATCs have audible distortion, because I know that they don't.
Even with facts and figures you still bury your head in the sand... oh well
Distortion is more than just harmonic's. There's many other kinds including IMD, doppler, phase, amplitude, cabinet resonances/colouration, diffraction etc. etc. Don't fixate on THD because its only a small part of the picture.
Some time ago I used to think the Mackie HR626 had low colouration/distortion... until I broadened my horizons. There's always something better that will redefine what we consider a benchmark, what you consider excellent today quickly becomes merely good or even average tommorow.