Such a solid foundation is properly built upon and the rest of the tonal structure quickly described. It continued balanced/neutral through the mids and into the treble which was just an iota mild. The sum total was very even to show just a subtly sonorous gait. It reminded me of the €26'000 Dynaudio Confidence 50 though the Dane wouldn't have matched the bass reach to manage equivalent bandwidth. It did however exhibit a similarly gentler top end. Acapella offer jumper settings but with ±0.5dB steps, those don't turn whole worlds. I favored the zero position.
Coherent tonality is important but doesn't explain—or at best only partly—the special touch or magic of Acapella's High BassoNobile MkII. After all, even-handedness with just a skoch of warmth plus very broad bandwidth can be had elsewhere, too. The special magic in the mid and high registers was due to the exceptional resolution of the horn whose five octaves emerged seamlessly from a single 1" dot in space. And to avoid any losses in translation, resolution was so high that it never felt paraded on the proverbial silver tablet. That'd be hifi artifice and diluted not uncut stuff. The latter includes all of music's attendant noises like finger-on-string changes, inhalations between sung sections, a chair squeak or score turn but presents as casual asides, never nerdy highlights.
Hence sundry player noises seemed rather less important and this extreme magnification power far more significant for truth of timbre and venue atmospherics. Those aspects became vital reasons why classical music in particular sounded so utterly terrific. To realistically render stringed instruments is a black art of sorts. It relies on a fully elucidated overtone spectrum. It's not about coarse quantities but capturing the spectral very subdued harmonics cleanly and in the right proportions to sum to the correct tonal colors.
Perhaps a nearly full-range horn with compression tweeter wouldn't be ideal but one can't generalize. Blumenhofer's Grand Gioia 2×10 does far too well on classical. Nonetheless, this proud owner of them must confess that the hyper-spherical horn of Acapella still performed in another league. Violins and cellos felt less pale and porous, their timbres more wholly retrieved. That massed string groups also modeled in more tactile fashion was a related gain. Once more this recalled Dynaudio's Confidence 50 albeit at not quite this extreme level of easeful resolution.