Digital Processor Reviews

Listening through the two HiFiMan headphones with both the HFM EQ curve and XSpace turned on, live music was brought (back) to life. Kicking off with some post-bop that swings hard, I dug into Lee Morgan, The Complete Live at the Lighthouse, Hermosa Beach, California (24/192 FLAC, Blue Note/Qobuz), which was recorded in the summer of 1970, less than two years before Morgan's death at age 33. Morgan's off-the-cuff introduction felt alive and immediate, breath hot on the mike, casual demeanor tangible. A cash register dings near the end of this two-minute segment. I was transported to the venue.

The ZEN duo conveyed those microdynamic details that evoke artists' unique styles and techniques. On "I Remember Britt [Set 2 – Friday...]," during Bennie Maupin's solo about 2:40 in, the flute's notes emerged spacious and light as air. Clear articulation; no shrillness. I could hear the breath behind the music and the variations of embouchure and air pressure. As the sounds of a güiro emerged from the right background about halfway through the track, I could feel the stick scraping across its wooden ridges.

I was craving more live and lively music. Philadelphia natives Low Cut Connie give off a rollicking good-time vibe, led by singer/pianist Adam Weiner's raw, frisky energy and full-on–ham stage presence. He's especially a hoot to watch live. I put on the band's Tough Cookies: Best of the Quarantine Broadcasts (16/44.1 FLAC Contender Records/Tidal). These are stripped-down recordings made during lockdown livecasts. On their spare rendition of Bowie and Eno's "Heroes," piano and tambourine details came through cleanly. The iFi setup conveyed the drama and earnestness of Weiner's delivery on his rendition of "Ain't No Sunshine." Ditto for the snippet of The Good, the Bad and the Ugly theme he bangs out on an upright piano.

The differences with or without the HFM (or HD 6XX) EQ and/or XSpace on were subtle, but usually I listened with both on. When I turned off the HFM EQ, some image edges became less clear and showed less separation. The sound was perhaps a little less smooth and a touch drier. Turning off XSpace resulted in less aural breathing space between headphones and my eardrums: As claimed, the space was more inside my head.

Ready for some familiar fare, I cued up the Bill Evans Trio's Sunday at the Village Vanguard (16/44.1 FLAC, Riverside/Qobuz), widely considered to be among the best live jazz recordings. On "Solar," Scott LaFaro's solo emerges from Evans's comping at around 3:50—vivid and full of body and texture. With XSpace on, it seemed to come from behind me, left of center amid some quiet audience chatter and Paul Motian's crisp cymbal taps. Turning off XSpace rendered this placement more like what I'm used to hearing with loudspeakers. With XSpace off, the instruments seemed closer, as if my ear were leaning in toward the double bass. XSpace did its job here—it created a more immersive, spacious experience—but in this case I preferred the experience better without it.

I did some passive listening with XSpace on, to Miles Davis's "Human Nature" from his late album Merci Miles! Live at Vienne (24/48 MQA, Warner Records/Tidal). That is, I was listening passively until the music yanked me out of my concentration on my task—like, whoa, what just happened? The music sounded so far outside the headphones that, for a moment, I wondered where it was coming from.

Electronic music was rendered with punch and clarity. Bass gave the impression of having more extension than it should have, especially through/with the HiFiMan headphones, which (subjectively) are less extended than the Prymas but also more detailed.

Switching musical gears, I put on LCD Soundsystem's This Is Happening (Deluxe Edition) (16/44.1 MQA EMI/Tidal). Filled with soft-to-loud dynamic contrasts, this album should be a wild ride. The ZEN's quiet backgrounds (with both the HE4XX and HE400S) allowed these dynamic shifts to emerge on tracks like "Dance Yrself Clean," especially its long, steady-build intro and the final wind-down. Attacks on bongos, congas, and cowbell were sharp and clean. "Pow Pow" was presented with plenty of, well, pow pow, and a satisfying low end. The bassline hit extra deep and funky, a bit thicker through the Prymas, which isn't a bad thing with this music. (Even with the iEMatch inline, I had to toggle the gain button back to the 0dB setting for those more sensitive 'phones.)

Tonal balance with the ZEN set seemed extended and neutral, with rare hints of brightness. It's hard to sit still listening to the Delvon Lamarr Organ Trio's Live at KEXP! (16/44.1 FLAC, Colemine Records/Tidal). Their instrumental rendition of Curtis Mayfield's "Move on Up" came through the ZEN Signature Set (HFM) with great pace and energy. If you aren't tapping your toes or nodding your head in time to tracks like this, check your pulse. Lamarr's Hammond B3 possesses voicelike qualities and, through the ZEN set, plenty of air. Turning on HFM EQ improved organ tone, but the guitar edged toward brightness on "Memphis," especially through the Prymas. On the other hand, the ZEN duo served the hard-hitting percussion on that track well.

The Beastie Boys' sample-laden classic Paul's Boutique, which I normally listen to on vinyl, translated well to headphones (16/44.1 FLAC, Capitol Records/Tidal) with the higher-impedance Sennheisers and their matching amplifier. On "Shadrach," the samples integrated better, sounding more like actual music than samples patchworked in.

There are priceless lyrical rhymes in this music, like, "I'm long distance from my girl and I'm talking on the cellular/She said that she was sorry and I said, 'Yeah, the hell you were.'" Listening to the trio trade vocals on tracks like "High Plains Drifter," it was easy to visualize them popping in and out of mike range, in and out of the frame. This sense of live action captured made these tracks even more fun than they already are.

Changing vocal styles completely, Over the Rhine singer Karen Bergquist's nuances can be subtle—as on "Trouble" from The Trumpet Child (16/44.1 FLAC, Great Speckled Dog/Qobuz). Here, her expression lies somewhere between vampy and campy, sultry and playful. Not all systems can convey this. Through the HE4XX with the iEMatch, volume set at 11:00 or 12:00, gain set to 12dB, her voice sounded natural, as she sounded when I've heard her live. Instruments sounded as they should, too: Linford Detweiler's sparkling piano; strings; what I think is bass clarinet in the left channel along with gently thumping low brass—all rendered in full.

On the Breeders' Pod (16/44.1 FLAC, 4AD/Tidal), Steve Albini's production struts, stomps, and swings. Percussion attacks rocked my world, snapped me out of autopilot. Kickdrum sounded full and expansive on the "When I Was a Painter" intro and on intermittent breaks. Perhaps the HFM EQ curve's upper/ midrange bumps bolstered those leading-edge transients. It's a kick to hear things you hadn't noticed before on familiar tracks. I detected more raspiness in Kim Deal's voice, screeching to near-straining at times.

Comparisons
I was curious how the AudioQuest DragonFly Cobalt USB headphone DAC would compare to the ZEN DAC/CAN separates. Both delivered detail and a sense of the recording space. A listen to the Andrew Bird/Fiona Apple folksy duet "Left Handed Kisses" (24/96 FLAC, Concord Loma Vista/Qobuz) through the ZEN DAC and CAN amp (and the 4XX and HD 650 'phones) sounded full, up-close, and substantial. Apple's warm vibrato stood out. The chimes struck cleanly, sustained clearly, and decayed slowly. With HFM EQ on, these seemed a bit more amped up, with detail slightly heightened.

I swapped in the DragonFly Cobalt, matching volume. With slightly less separation between elements, the same track sounded more blended, more of a piece. Attacks might have been a hair less razor-sharp, but nothing stuck out or seemed out of place or exaggerated. Apple's and Bird's voices were distinct and pleasing. The presentation was well-balanced, with perhaps fewer peaks and valleys in the sonic landscape. Things seemed less fortified. Less dynamic perhaps, but it seemed more natural in some aspects.

Finally, for fun, I tried the ZEN DAC Signature V2 in my main system, using a Pentaconn-to-XLR adapter I'd ordered online to connect the ZEN DAC's output, balanced to the MBL N51 integrated amplifier's XLR inputs. I matched SPL as best I could, bypassing the N51's volume control and using the ZEN DAC's. The sound into the MBL 120 Radialstrahler speakers exceeded my expectations. Detail was maintained and the sound was robust, full, and clear. Backgrounds remained quiet.

Conclusion
I was surprised that these ZEN Signature sets, used as directed, produced too much volume with the recommended headphones. Once that was fixed, with the iFi iEMatch attenuator, the ZEN Signature sets delivered highly resolved, clean, pristine, dynamic sound. The amplifiers are powerful. Backgrounds black as a new-moon nighttime sky brought musical details to the foreground. These two components sounded more expensive than they are and offer impressive sound quality—and a bit of style—for not a lot of money.