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MQA, Bowie & headphones

  • “As they pulled you out of the oxygen tent you asked for the latest party.” – David Bowie, Diamond Dogs

    If the oxygen tent is the audiophile bubble then the latest party is that thrown by MQA. Bob Stuart (of Meridian) and Peter Craven’s audio encapsulation system not only folds hi-res content down to 24bit/48kHz source files, making them streaming-ready, but also applies a filter to the original file as created by an ADC and to the DAC during playback, promising to remove the “time-smearing” effects of pre-ringing from both. In short, MQA offers: 1) hi-res audio origami; 2) ADC correction; 3) DAC correction.

    Zooming out, we see MQA as an end-to-end transmission system – studio to listener – where a 24bit/48kHz MQA master file can be authenticated by an MQA-certified DAC. The A in MQA is Authenticated. The M, Master.

    A certified DAC’s display or LED lets the listener know that what they are hearing is the same that left the studio, after which any hi-res content is unpacked and the file returned to its original 96kHz or 192kHz (but sometimes higher) sample rate. In MQA parlance, that’s file decoding. Also residing in an MQA DAC is the filter code that optimises the downstream DAC chip’s performance – according to MQA, their apodising filter reduces pre-ringing. MQA refers to this as rendering.

    MQA has also made the partial leap to software. Master file authentication and the first unfold can also now be executed by select software apps: in Tidal’s desktop app, Audirvana+ and – soon – Amarra. Clearly, the MQA ship is gaining momentum. Perhaps why some commentators have turned up the critical heat: Douglas Whales of Glasgow’s retail outlet The Music Room MQA as a ‘codec’ needed by no-one. Linn’s critique centres on MQA’s alleged money grab. On the lossy nature of MQA’s file encapsulation method, the debate continues.

    One thing’s for sure, prior to numerous MQA albums landing on Tidal’s Hifi Tier in January, opinions were more numerous than first-hand experiences i.e. listening. Bob Stuart might feel that, at the time of writing, this imbalance remains.

    This publication has hitherto covered both sides of the MQA coin: 1) What MQA technology promises but also 2) the need for a much broader catalogue; 3) How MQA sounds compared to standard hi-res but also 4) DAC manufacturer objections; 5) Licensing deals signed with major labels but 6) the potential pitfalls of a closed digital audio ecosystem; 7) MQA’s arrival on Tidal but also 8) calls for a deeper technical analysis of what’s going on under the hood.

    Today’s post returns us to that process. A year ago I A/B-d MQA and standard hi-res content via a loudspeaker system: Spatial Audio Hologram M4, fronted by the MQA-certified Mytek Brooklyn DAC. Those listening sessions were conducted with content privately provided by Bob Stuart and co. In other words, audiophile music.

    However, with more mainstream music now available in MQA via Tidal Hifi, streamed via Audirvana+ for maximum sound quality, and a different, more affordable MQA-certified DAC to hand – the Meridian Explorer2 (€249/US$299) – it’s time to listen again.

    I wear them like a second skin: David Bowie’s gritty Diamond Dogs and plastic-souled Young Americans. The recent (2016) remasters are, to these ears at least, the finest sounding reissues to date. And they’re on Tidal. In MQA.

    When either album is streamed to the Explorer2 via Audirvana+, the software confirms its validity but leaves it well alone. Audirvana+ is only licensed to carry out the first unfold (decode). For these 24bit/192kHz Bowie reissues, that limits us to 24bit/96kHz with none of the MQA-certified DAC’s filtering (rendering). Per Audirvana+’s settings panel, we tell it to forward our Bowie untouched on to the Meridian DAC – it will handle full decoding and rendering.

    The Meridian tube’s blue LED confirms the stream’s ‘Studio Master’ authenticity – that it has seen zero alteration – and the twin white LEDs both illuminated tell us that the stream has been unfolded (decoded) twice, first to 24bit/96kHz and then again to 24bit/192kHz. The stream is also rendered by code residing on the Explorer2’s XMOS DSP chip. This is the full MQA monty: hi-res files filtered at source by the MQA algorithm, folded up to 24bit/48kHz for internet streaming, then unfolded and filtered again by the D/A converter.

    At one end of the Explorer 2, a single mini-USB input. At the other, two 3.5mm outputs: one variable, with 0.47 Ohm output impedance, for headphones; and one fixed at 2Vrms for listeners doing the volume attenuation downstream e.g.amplifier.

    The playback chain was set as follows: Macbook Air 11” w/ Audirvana+ v3.0 → Meridian Explorer2 → iFi micro iDSD Black Label → AudioQuest NightOwl Carbon / Audeze Sine.

    BUT! We’re not concerned here with how the Meridian DAC’s full handling of MQA compares to that of Audirvana+ 3.0’s partial handling…yet. Nor are we concerned with how the Explorer2 compares to other DACs – hence the addition of the recently reviewed iFi micro iDSD Black Label as headphone amplifier to the Explorer2’s line-level output.

    These same 2016 David Bowie remasters sit on my hard drive, in 24bit/192kHz PCM, sourced from HDTracks and untouched by MQA.

    My question was simple: how would MQA-d Bowie compare to the vanilla, non-MQA hi-res version?
    Let’s cut to the end – in a word, it’s a bit better. Echoing the findings of my 2016, Australian-based loudspeaker listening tests, the horn section of “1984” sounded wetter with more abundant blat. The guitar grind of Diamond Dogs’ title cut comes off as less hard-shelled, less rigid and the drumline more dynamically supple.

    Listening to “Fame”, Young Americans’ closer, I took note of a more expressive midrange, most evident on the acoustic guitar strum that precedes the track’s full swagger. Back to drums again: in MQA form, Dennis Davis sounds more alive and from Carlos Alomar’s guitar licks I heard finer gradations of tonal shading.

    Also on Young Americans, “Fascination” uses additional instrumental and vocal layers to build its inner intensity. From the MQA version, I was more easily able to mentally visualise the pop-up book illusion of player outlines and their positioning.

    MQA makes these two Bowie albums, through this hardware combination, sound a little more believable. However, it doesn’t render HDTracks’ hi-res versions unlistenable. Bringing this Starman test back to earth, the audible deltas are anything but night and day.

    Neither does one version ‘destroy’ the other. Such untethered hyperbole is for forum dwellers. On a daily basis, away from the review job, I’d be more than content with the Redbook CD version of these recent remasters. My absolute preference, even over MQA, is to spin the vinyl copies; not because they sound better but because savouring music is more than just a game of optimising sound quality.

    One could argue that only the most anal-retentive listener will want to make the switch from standard hi-res to MQA; and there’s no denying there might be a little gold waiting for him should he do so. That’s assuming all things remain equal. Which they don’t. Least of all in an audiophile’s system which is more often than not in a constant state of hardware flux.

    Removing the Meridian DAC from my headphone system, connecting the iFi micro iDSD Black Label to the Macbook directly via USB and having Audirvana+ handle the first unfold and without MQA DAC correction still sounded better, fuller, richer than anything heard from the previous A/B, MQA or not.

    Perhaps iFi’s DAC implementation is better than Meridian’s. Or maybe, now sitting on a more proximate board, a shorter signal path between DAC and amplifier comes into play. Or maybe it’s the dispensing of the iFi supplied 3.5mm-to-3.55m flylead that did the trick. Likely that all are contributing factors. Whatever it is, piling on better hardware brings forth more satisfying audible gains than the move from vanilla hi-res to MQA alone.

    The wo/man in the street using basic earbuds probably wouldn’t hear the afore-detailed differences between MQA and standard digital audio. Besides, s/he’s better off first making the jump 1) to a nicer sounding pair of headphones, 2) to a better DAC/headphone amplifier and 3) from lossy to lossless streams. Only then might MQA enter the picture.

    One final wrinkle to trip us up: with Aurdirvana+ 3.0 handling the first unfold and pouring the MQA’d remasters as 24bit/96kHz into the iFi DAC/amp, Diamond Dogs and Young Americans still sound marginally better – more supple, better separated – than HDTracks’ 24bit/192kHz versions. The delta isn’t as wide as with an MQA-certified DAC but it’s there.

    Does the iFi DAC intrinsically sound better with 96kHz than 192kHz or is it Bob Stuart’s studio-level sauce – ADC time smearing correction – that has MQA sounding better even without an MQA DAC in play? Performing a similar A/B with an AudioQuest DragonFly Red tells us it’s more likely the latter; that MQA’s de-blurring filter applied to the studio master before it leaves the label/distribution house affords the listener more audible benefits than an uptick in sample rate alone.

    This brings us to an unexpected MQA sweet spot for this website’s readers, one that pulls from numerous directions: 1) let the digital audio hardware do the heavy SQ lifting in choosing the subjectively best DAC, MQA-certified or not, and 2) use that DAC to stream MQA content from Tidal but 3) through software that can carry out the first unfold.

    In other words, your next DAC purchase should be the best sounding to your ears, irrespective of its ability to fully decode or render MQA. Reframe the latter as a bonus and not a prerequisite. Those dismissing a DAC because of its lack of MQA support are allowing the tail to wag their (diamond) dog. They’ll catch their death in the fog.

    Further information: MQA | Meridian

    Written by John

    John currently lives in Berlin where he creates videos and podcasts for Darko.Audio. He has previously contributed to 6moons, TONEAudio, AudioStream and Stereophile.

    Darko.Audio is a member of EISA.

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