Hi FranzSchubert, old Gustav does sound magnificent on my Mahlers with subwoofers firing outward + 312 + Capri. the extension is phenomenal. . . but it is not bloated at the bottom, nor it ever becomes tizzy at the top. . . and harmonic exposure is tops. Macro and micro dynamics is to die for. . . but it never sounds 'artificially pumped'Good idea to remove speaker grills for critical listening. . . . lowest level detail excels with grilles off. Oh yes, did I mention bass drum is stigean? I still have some relatively weak links in the system: Cardas Golden Ref speaker wires and a Cardas Golden Ref PC currently on Capri. PC on 312 is Shunyata Anaconda Helix Alpha, which is excellent for this particular application. my AudioQuest Sky ICs work beautifully from X-01 LE to Capri to 312. I will try some new Synergistic wires soon and will see how they behave/compare. Guido