Meridian Explorer2 D/A headphone amplifier Page 2

MQA also uses a clever approach to nondestructive compression (in interviews, Stuart has used the phrase analog-lossless) in which timing-relevant data from the higher sampling frequencies—including the range above the range of human hearing, where music still has energy—are folded back into the first 44,100 samples and reversibly buried below the noise floor. In this way, MQA claims to deliver music with studio-master quality in packages small enough to conveniently download and stream, and in a form its exponents say sounds better than a CD even if you don't have an MQA decoder.

If MQA works as its designers claim, the only apparent casualty is a few low bits in the 24-bit/44.1kHz file, well below real-world noise floors, and some supersonic musical content, which is retained but at lower resolution. There is, perhaps, some legitimate cause for skepticism: MQA compression can seem almost magical, claiming that even DXD files—32/384—can be compressed to 24/44.1 while sounding better than the original high-resolution files. Nevertheless, the literature available so far about MQA—in particular at the MQA website (, in a "Journal of the Audio Engineering Society, and in a paper presented at the 2014 AES Convention—convinces me that MQA is a real and serious technology.

Listening 3: Explorer2 with MQA
Ultimately, though, the proof is in the listening. MQA has been demonstrated at audio shows for a couple of years now, and the audiophile press has been enthusiastic. Several Stereophile writers have attended demos and come away gushing. A few mildly critical perspectives have appeared, a couple from notable experts, but the number of critics is small.

After months of teasing, MQA escaped the laboratory in early February via a firmware update for several Meridian processors, including the Explorer2. I downloaded and installed the update—it was easy and took moments—and hunted up a handful of sample recordings. Bob Stuart and the MQA folks provided a Dropbox full, and I downloaded half a dozen or so interesting but unfamiliar albums from the Norwegian record label 2L, which offers its entire catalog in MQA and a range of other formats, ranging up to DXD (32/384 PCM) and double-rate DSD.

The first recording that made the little light on my Explorer2 turn blue—indicating that an MQA Studio file is playing—was Sally Beamish's Under the Wing of the Rock, with viola soloist Soon-Mi Chung, and Oyvind Bjora conducting the Oslo Camerata (SACD/CD, 2L-119-SACD). Listening through my Sennheiser HD 650 headphones and then my home system, I was struck by a remarkable sense of intimacy, a close connection to the solo instrument. A well-played viola—a rare enough thing—produces a satisfying buzz rich in wood and rosin; on this recording, Chung's viola seemed to be vibrating inside my own brain, and not just when I was using headphones. It was an auspicious debut.

Several weeks later, long after that first impression of MQA, I researched the manner in which Under the Wing of the Rock had been recorded. This proved easy—there's a photo from the recording session on 2L's website, and Morten Lindberg, 2L's recording engineer, is a Facebook friend. Soon-Mi Chung stands on a platform maybe 30" high, her viola tucked under her chin. Fifteen other string players surround her, sitting in chairs on the floor. An array of microphones is centered a few feet in front of Chung, just a little higher than her head. The distance between her instrument and the closest mike looks to be about 6', maybe a bit more. I asked Lindberg to confirm the distance: about 2m from instrument to mike?

"That sounds about right."

I told him that, with MQA, it sounded much closer.

"Yes, that's what the deblur process of MQA does."

For all the discussion of jitter over the last two decades—and all the discussion of minimum-phase and apodizing filters—little has been written about what timing errors sound like and how they affect our perception of music. Here was an expert with wide experience doing exactly that. I kept the conversation going.

"Our perception of time-smear is very similar to how our mind deals with reverb," Lindberg told me. Time smear in digital recordings—the cumulative effect of all those low-pass filters—creates a sort of unintentional reverb, obscuring detail in time and space. This, he emphasized, is more aural analogy than precise technical parallel: "Don't take these analogies too literally, as the converter blur is in the microseconds and early reflections of a reverb is in the milliseconds. But the modeling and effects on our auditory perceptions are comparable."

What about pre-ringing—in which, because of the digital filters used in some converters, some of the ringing comes before the actual sound? What does that sound like?

"In the microseconds, you can't really identify it as an independent component," Lindberg replied. "It just sounds like a bad converter, smearing the image."

At this time scale, then, ringing is ringing—except that, because it's unnatural, the effect of pre-ringing is greater than you'd expect from its time scale of just a few microseconds. All ringing has a reverb-like effect on recorded sound, Lindberg suggested, but pre-ringing has more.

Lindberg's observations corroborated what I'd heard weeks earlier from the Explorer2 and MQA, and have been hearing ever since: That sense of intimacy and closeness—of almost exaggerated texture and timbre (exaggerated because recordings rarely capture it, and we rarely sit close enough to hear it in concert)—is apparently just what one would expect MQA's technical advantages to convey. As it happens, it's precisely those elements of the sound—the buzz, the rosin, the wood—that I most love about music. For me, a well-recorded cello is like a massage.

Okay, maybe the marketing of MQA—those videos of pretty young people in the throes of passionate listening—is a bit over the top (footnote 3). And it's possible that, as I listen more, MQA's appeal will fade. Maybe I'll notice some annoying artifact, or those favorable impressions from my first several weeks of listening won't be borne out over time. I don't expect that, though. For now, MQA has me excited about the future of recorded music.

Oh, right—that component I was reviewing . . .
Leave MQA out of the mix, and the Meridian Explorer2 is a fun, capable audio device at a cost that audiophiles—and anyone else who's accustomed to audiophile prices—will likely find more than fair (although the price per pound, $3189.33, is higher than a piece of high-end Bluefin sashimi, which the Explorer2 somewhat resembles). But when you add MQA into the bargain, the value proposition changes dramatically: Here's an opportunity to get in fairly early on a new and exciting development in high-end audio for not much money. As I write this, the Explorer2 is the only MQA-capable device anywhere near its price point.

As winter passes and the hot season approaches, the question remaining about MQA—and the value of the Explorer2—is how much music will be available in MQA format. Even the best new format isn't worth much if the music you love can't be found in it. (For me, it's worth it just to play around, regardless of how it turns out.)

But things are looking promising. Tidal announced months ago that it will start streaming MQA sometime this year. The CEO of Atlantic Records is enthusiastic about MQA, so hopefully we'll at least soon see MQA versions of those great Charles Mingus records—or Ray Charles, or Coltrane, or Zeppelin, or the Modern Jazz Quartet.

Spencer Chrislu, MQA's director of content services, paints a rosy picture: "Labels and services are excited and they're on board," he told me in an interview. "You'll definitely see things happen very, very soon."

Footnote 3: The MQA folks assure me that those videos are real. Watch singer-songwriter Amy Duncan listening to the MQA version of her new album here.
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Hi-Reality's picture

Dear Jim,

Thank you indeed for this good review of the Meridian Explorer². I was looking forward to read little more about your MQA listening impressions.

Around 3:00 on 2L's 'magnificat 4 et misericordia' the highlight of the track starts with the Nidarosdomens jentekor & TrondheimSolistene to then move on to merge with the voice of the simply beautiful soprano, Lise Granden Berg, (3:34) to be joined by the organic sound of the Magne H. Draagen's organ (3:54).

The entire track is just a pure joy, bringing tears, through the current prototype of the Hi-Reality system and I intend to seek Morten Lindberg's permission and support to demo a purist audiovisual version of this magnificat at the launch event. This is one of my dreams for this project.

Skål, Babak
Hi-Reality Project

Steve Graham's picture

Maybe I'm naïve but I hope this will fulfill the lost promise of HDCD a couple of decades ago and much more as well. Now that WMG is on board hopefully others will follow. Let's hope that on both the hardware manufacturers and music distribution side it doesn't suffer from the NIH syndrome. I'd especially like to see Ayre and PS Audio, whose products I covet, get on board. I hope my location doesn't preclude me from downloads, I'd much rather pay for something than steal it but I'll cross that bridge when I come to it.

A Question for JA: When you say the Green LED lit up to show MQA encoding but not the blue to show Authentication does that mean that the impulse response of you A to D converter was not factored into the file you received?

With regards, Steve

IgAK's picture

"The CEO of Atlantic Records is enthusiastic about MQA, so hopefully we'll at least soon see MQA versions of those great Charles Mingus records—or Ray Charles, or Coltrane, or Zeppelin, or the Modern Jazz Quartet."

Another excuse to re-sell us the same material yet again! Well, if it results in making an improvement a success, I suppose it's for the best, regardless of what their motivation really is.