Floor Loudspeaker Reviews

The crossover between the tweeter and midrange horn is set to 5kHz; that between the midrange and woofers is 800Hz. Electrical connection to the speaker is via a pair of five-way binding posts on top of the internal shelf behind the tweeter module. Flying leads emerging from the woofer enclosure connect to binding posts on the bottom surface of the midrange module; another pair of leads terminated in an RCA plug connects the tweeter in parallel with the main drive.

The Acapella High Violoncello II is superbly finished. The woofer cabinet is finished in piano-gloss black or white, and the midrange horn is available in high-gloss automotive paints. Assembled, each speaker weighs over 300 lbs.

Setup
Brian Ackerman of Aaudio Imports, Acapella's US distributor, helped unpack the High Violoncello IIs from their three crates and assemble them in my listening room. He started off with the speakers equidistant from my listening chair; then, using recordings with which he was familiar, he methodically adjusted their positions to optimize the low-frequency balance. Once the transition between the upper bass and lower midrange sounded optimal, Ackerman experimented with toe-in to get the sharpest stereo imaging and the best blend of the midrange and tweeter outputs. The tweeter control of each speaker was left at its factory setting (8:00), and the two switches per speaker that adjust the midrange sensitivity were left at their "0" positions. Once everything was sounding as he had expected, the final step was to screw the small carpet-piercing spikes into the four feet of each plinth. This added even more definition to the stereo imaging, as well as a final polish to the midbass region. Having declared himself satisfied, Ackerman left me to spend the next six weeks with the speakers.

Sonics
I left the High Violoncello IIs in automatic mode, in which the tweeters turn themselves off after about 20 minutes of inactivity. When you next play music, there is at first no high treble. There is then a click and a shushing sound, followed by another click and an even louder noise as the combustion chamber heats up and any dust particles are burned away. A third click signals that the chamber is at its operating temperature, the level of the arc power supply is reduced to its normal value, and the noise stops, leaving me with perhaps the purest-sounding high frequencies I have experienced.

For those whose memories of ionic tweeters from other companies were colored by the unmistakable smell of ozone: I could detect no trace of that destructive gas coming from the brass horn. And throughout my auditioning, I kept returning to the Acapella tweeter's complete lack of grain, its seemingly endless HF extension. However, I had started my auditioning with the Classé CTM-600 monoblocks, which were resident in my system during Brian Ackerman's visit. The 600W on tap were incongruous, given the Acapella's very high sensitivity, but the fact that the Classé is deathly quiet made it a good match for this speaker. (High sensitivity in a speaker ruthlessly reveals any noise problems that an amplifier might be suffering from.) And though I loved the iron control the Classés exerted on the woofers and the effortless dynamics, I couldn't escape the feeling that, in the treble, I was getting too much of a good thing. The high frequencies floated a bit forward in the soundstage. For example, the sibilance of Jennifer Warnes' voice on her Famous Blue Raincoat (CD, Private Music PVT2092) sounded a little disconnected from the rest of her voice. The sizzle of the cymbals in the first of Britten's Four Sea Interludes, with the Kansas City SO under Michael Stern (SACD, Reference RR-120 SACD), was a little detached from the body of the instrument's sound.

Some of this lack of integration was simply that the tweeters were too high in level—analog tape hiss on older recordings was very audible, for example. I backed off the tweeter controls, but could make only a slight adjustment before the tweeters were completely muted. I changed from the Classés to the Simaudio Moon Evolution W-7, but the treble discontinuity remained, while the sense of effortless dynamic capability was a little reduced. Brian Ackerman had recommended I try tubes, so I borrowed the sample of the Balanced Audio Technology VK-55SE that Wes Phillips reviewed last April.

That was more like it. There was still a bit too much top-octave energy in absolute terms, but the treble receded a little in the soundstage, falling into better balance with the upper midrange. I continued my auditioning with the BAT amp, but didn't really feel I was getting the best of the High Violoncello IIs until I set up the Audio Research VSi60, which Bob Reina reviews elsewhere in this issue. This tubed integrated amplifier, fed directly from the dCS Puccini, got the balance between the high and low treble regions correct. The chiff of Carol Wincenc's flute in the Allegro of the Mozart Flute Quartet, K.285, on Editor's Choice (CD, Stereophile STPH016-2), for example, was now properly integrated with the body of the instrument's tone. The Audio Research also usefully fleshed out the Acapella's low frequencies. In fact, I think it was this change in bass character that changed my perception of the high treble rather than any actual reduction in tweeter output with the tube amp.

The Acapella excelled in its presentation of recorded detail. It's a reviewer cliché to say that you heard new things in familiar recordings, but this was true with the High Violoncello II. As familiar as I am with Van Morrison's Live at the Belfast Opera House (CD, Mercury 422 818 336-2), I had never before been able to grasp what he was mumbling ("yeah, yeah . . .") before he starts the verse in "Rave On John Donne." Differences in the acoustics surrounding individually miked instruments and voices on the 2009 Beatles remasterings (USB edition, 24-bit FLAC files, converted to ALAC) were made more audible than the mixing engineers had possibly anticipated—as were the early reflections of the piano's sound from the walls of the small recital hall in my 2000 recording of Robert Silverman performing the complete Beethoven Piano Sonatas (24-bit/88.2kHz master files, released on CD as OrpheumMasters KSP-830).