This is the second "quantum" filter from the mind and hand of Alan Maher I've tried. Since I'm assuming that diminishing returns always apply - my system already includes quite a few of Alan's filters - I was expecting a modest effect. And it was modest when the filter resided on the speaker. It sat there for five weeks breaking in.
On Alan's advice, I switched the filter to the amp and waited a few days. Kaboom! Instant holographic soundstage. In other words, the quantum SC excels at spatial information. But not just the sound of the venue, it also reveals the individual space occupied by different instruments. Along with the filter's benefits to timbre, the filter provides an organic, very natural, fleshed-out view of instruments. Well, not a view, since it is more like just listening to live music.
That said, you do need to feed it a good signal. While my source/preamp was being upgraded (a whole other story - Alex Paychev is a genius), a DVD was the source. Awful stuff. But, feed a good signal and the gains are considerable.
Needless to say, the speaker cable works wonderfully with the Quantum AC filter (now called the studio, I believe). This is really good stuff. Too good to keep to oneself.