Awesome! Your speaker cables finally broke-in!
I'd venture to guess that most of us are in this hobby for those 'oh wow!' moments. Kinda like golf, or home espresso. You have that one good shot and then spend all your time and $$$ trying to get that shot again.
<Opinion Alert>
IMHO, volume level shouldn't have much to do with transparency. A disapearing soundstage is a function of having good audio equipment that's set up and calibrated correctly, quality speakers that are
positioned properly, room acoustics, and the recording itself.
</Opinion Alert>
I bolded the speaker setup line, because thanks to many tips from other members here, I have found that to be absolutely critical. To get that, 'where'd the speakers go' feeling, your speaker layout has to be just spot on. I have found that properly toe-ing in your mains and playing with seating position and distance is critical to getting that feeling.
Regarding hardware, you will find opinions that amps and speaker wire makes a difference too. Many claim that expensive wires make all the difference, others claim hogwash. Still others say the amp makes a difference, and I'm being dragged behind that wagon. Others will vehemently disagree with me, but I feel that my M80's vanish more readily when powered by my LPA-1 rather than the AVR. You've got an MPS (lucky dog!), and so you might be a believer too!
A good friend has an uber-buck system in which he's spent more on cables and speaker wire than I have on my whole system. From the 'sweet spot' chair, it's mind-blowing: no speakers, no room, no nothing - just you and waves of music. Depth, spaciousness, and precise instrument positioning. It almost borders on too real, as your senses disagree with each other nearly to the point of confusion. Feels very much like your sitting in the perfect seats in a large concert hall. Instruments seemingly being played from somewhere out in the yard, or from the next room - but your eyes clearly tell you that you're sitting in a smaller space. However, as you move away from that sweet spot, the position of the speakers becomes more discernable and the system goes back to just 'amazing'.
But the point is, his system sounds like that during both loud *and* soft passages; it's all a function of room layout, speaker positions, the recording, and equipment.
