Krell Reference 64 digital processor Page 4

This dynamic quality heard in the bass extended to the rest of the spectrum. The Reference 64 was particularly adept at portraying microdynamics—the small-scale transient aspect of music such as percussion, and the quickness of a drumstick hitting the drum head. The sound was the antithesis of slow, blurred, or fat. Macrodynamics—the sheer sense of slam and power—were also superb through the Reference 64. Orchestral climaxes were startling in their impact, a quality attributable to both the Reference 64's tremendous dynamics and lack of strain or congestion on peaks.

The Reference 64 had a terrific sense of pace and rhythm, in part because of the characteristics described above. The music had a power and drive heard only from a handful of products. Moreover, the tempo seemed faster and more upbeat through the Reference 64, further adding to the sense of the music's forward propulsion. I greatly enjoyed this aspect of the Reference 64.

The Reference 64's treble purity wasn't up to the standards set by the No.30 and SFD-2, tending to have a slightly grainy and untidy upper treble. This was manifested as an increase in sibilance and a slight "whitening" of sax and other brass instruments. The vocals on Michael Ruff's Speaking in Melodies (Sheffield Lab CD-35) and the previously mentioned Robben Ford discs were good examples of how sibilance became more noticeable through the Reference 64. Similarly, violins had a bit of edge and bite rather than a liquid texture. Use of the AES/EBU connection and the Time Sync function tended to ameliorate this characteristic.

Nevertheless, in comparison with the SFD-2 and No.30, cymbals had a slightly metallic character and a fine layer of grain overlaying them. The No.30 had a more delicate, subtle, and filigreed presentation of treble detail. Similarly, instrumental textures were slightly hard rather than lush and liquid. This didn't affect all instruments, only those with significant energy in the upper registers. I don't mean to imply the Reference 64 was hard or glassy; the Steinway on the Robert Silverman recording was never edgy or brittle. Instead, instruments such as saxophones took on slightly harder timbres. I stress that this characteristic—and thus my criticism—are minor: I enjoyed music to the fullest extent through the Reference 64.

In three-way comparisons between the Reference 64, No.30, and SFD-2, I had the unusual experience of liking the Reference 64 best on some music, the No.30 best on other selections, and the SFD-2 best on yet other discs. For example, on the very upbeat and rhythmically driving Michael Ruff disc, the SFD-2 was the clear winner. Its clean treble, immediacy, and driving bass best suited this music. The Reference 64 came in third with this disc; although it had the best sense of pace, the slightly untidy treble emphasized sibilance (especially on the background vocals). With the Robert Lucas CD Usin' Man Blues, I liked the No.30, followed by the Reference 64, with the SFD-2 finishing third. The SFD-2's forwardness made the harmonica too aggressive and in-your-face, while the No.30 had a sense of ease and a lack of hardness that made it the first choice on this music.

Finally, the Reference 64 clearly excelled in reproducing full-scale orchestral music such as Trittico (Reference Recordings RR-52CD). The Krell processor had more immediacy, palpability, and bite than the No.30, yet didn't go over the edge to becoming aggressive. Moreover, the Reference 64's precise image focus, depth, and finely resolved spatial perspective provided the most satisfying perspective on the orchestra. I also greatly enjoyed the Reference 64 on rock and electric blues—the terrific Robben Ford disc is a good example—for its outstanding sense of pace and rhythm.

In short, the Krell Reference 64 processor is among the best in digital processors. It had some qualities—rhythmic drive and soundstaging, for example—that set it apart from the competition. It didn't, however, have the treble smoothness or purity of the No.30 or SFD-2. Although these impressions were primarily from listening to the balanced outputs, the Reference 64 had all the qualities described from the single-ended outputs.

The Krell Reference 64 digital processor is among a handful of processors that can truly be called the state of the art. The 64x-oversampling digital filter, in particular, is an impressive technical achievement. Many of the Reference 64's unique musical qualities are perhaps the result of this sophisticated custom filter. Moreover, the Reference 64's cosmetics, build quality, and features (lots of inputs and outputs, and the Time Sync port) establish it as a real contender for the top echelon of digital processors.

Musically, the Reference 64's performance was clearly Class A. Its sonic strengths and weaknesses, however, lay in different areas of musical reproduction in relation to the other Class A processors. The Reference 64 was unequaled in its soundstage focus and ability to reveal a recording's spatial information. I also found its bass dynamics, sense of power, and rhythmic drive extraordinarily compelling musically. Potential purchasers should be warned, however, that the Reference 64's upper midrange and treble are less clean than those of the Mark Levinson No.30 and Sonic Frontiers SFD-2. Careful system matching is therefore essential in order to minimize the Reference 64's few shortcomings.

If forced to choose between the identically priced Reference 64 and the No.30, I would choose the No.30 for my particular system and tastes. In another system, or with a different listener, the comparison could go the other way. We all value different things in music reproduction; choosing one product over another is a matter of weighing the musical significance of each product's sonic strengths and weaknesses. The Reference 64 was clearly better at soundstaging and pace; the No.30 had a greater sense of ease and a more refined midrange and treble. It's best for you to decide which presentation you prefer. But if you're looking for the best digital playback money can buy, the Krell Reference 64 digital processor should be on your short list of products to audition.

Krell Industries
45 Connair Road
Orange, CT 06477-3650
(203) 298-4010