MQA Core vs. Hi-Res Blind Test Part II: Core Results

As you know, Part I - Procedure is now published. Within it, I laid out in detail the test, how it was constructed, and how data was collected. Today, we'll embark on the exploration of the data itself. While I will try to conclude with some general points by the end of this post, I will not have had time to analyze everything quite yet. I'm currently anticipating at least another couple of posts to fully flesh out the data set including posting some of the subjective comments made by listeners. I feel this is the only way to properly thank those who took their time and provide as much information as possible to answer any lingering questions.

Let's start... Today, let's focus on the "core" or "headline" results I think most of us are interested in. Who are the people who tested and submitted results? What overall were their preferences? What was the result for each specific track? How confident were the respondents about their choice? And how significant were these findings ultimately?

MQA Core vs. Hi-Res Blind Test Part I: Procedure

Introduction:

As you are probably aware, through the last 2 months on this blog, I've been collecting data to determine the audibility of decoded MQA versus the same piece of music originating from the "master" high resolution source. Please refer to the Test Invite article from mid July 2017.

Over the last couple of years, I have been curious about the MQA technique and followed the evolution of the "technology" as it has been touted as being the next step in digital music playback. Throughout the last 2 years, I have tried to develop an understanding of what it's doing beyond simply the superficial talk around being "revolutionary", "fundamentally changing the way we all enjoy music", nebulous claimed links to "neuroscience", or talk of bringing the "studio sound" to the consumer. If you look back, I have written articles looking at:

- Initial musings... 

- The undecoded MQA file. 

- Decoded vs. undecoded Explorer2 output. 

- Dicussions of MQA's partially lossy nature. 

- Comparison of TIDAL / MQA Decoding with "studio master" tracks. 

- Mytek Brooklyn hardware MQA decoding. 

- Discussion of digital filters and relevance to MQA. 

- Comparison between Meridian Explorer2 vs. Mytek Brooklyn ("Authentication?"). 

- Dragonfly Black MQA "Rendering" and filter. 

- Mytek Brooklyn MQA filters. 

- The "full monty" of MQA filters from the Dragonfly Black MQA-enabled DAC.

MUSINGS: Evidence of digital player jitter with asynchronous USB DACs? Melco N1ZS20/2 review in HFN&RR...

The UK magazine Hi-Fi News & Record Review is interesting. Like Stereophile here in N. America, it includes objective measurements. Over the years, I've seen times when they have criticized questionable "hi-res" downloads showing nothing more than upsampled music. But they also seem to like "showing" rather meaningless measurements such as a few years ago with their USB cable roundup.

Recently, I believe in the May 2017 issue, they reviewed the very expensive "cost-no-object" digital server - the Melco N1ZS20/2. This device is the "mk2" of their top-of-the-line music server/player with the capability for data output through ethernet or USB connection to one's DAC.

MUSINGS: How much amplifier power do you really "need"? Why not test for yourself?

Much has been discussed about amplifier power over the years; here for a short primer, here for a contemporary take with advice from Crown, and here for an oldskool audiophile take on the matter when dinosaurs and tube amps ruled the land (notice the positive sentiment towards even low power transistor amps compared to the low-wattage tube jobs in this article!).

We often hear the question: "How much power do I need?" A very reasonable query of course when we're thinking of buying a new amplifier.

The answer to that question of course really depends on your needs. The bottom line is that it really is about your context and preferences, the quantity and quality of the amplifier you need can vary based on all kinds of factors. When it comes to quantity, it will of course depend on the efficiency of the speakers you listen to along with size of your room, distance to the listening position, placement of the speakers, and absorptive/reflective surfaces in the space.

MUSINGS: Increasing the Dynamic Range of compressed audio with DSP... (And is this why vinyl DR is higher!?)

Sadly, the good doctor's diagnosis applies to too many of the recordings we listen to these days.

I mentioned last week a recommendation for July Talk's Touch album at the end of that post. There are a number of catchy and enjoyable tracks on there... However, if we put this album through the foobar DR Meter, unfortunately, we see an album with really nasty dynamic range compression - DR4. Yuck.

Hmmm... Is there any way to change that?

MUSINGS: The 3 Main Home Computers 2017 (Workstation, Server, Gaming) & Thoughts on Gaming Consoles (like the upcoming Xbox One X)...

In the heat of summer, it is nice to get some time off to fix up around the house and do something that I typically take no pleasure in - rebuilding computers and reinstalling the OS & software! It requires a level of "Zen and the Art of Computer Maintenance" that I can only muster up every few years :-).

If you're like me, at home, you might have a little cadre of computers for work and personal purposes. As painful as it is, every few years, I'll update the OS, maybe tweak the hardware here and there (everything from cleaning up cables, vacuuming out dust, updating motherboard firmware and drivers, and the occasional refreshing of the heatsink compound). Updating a less "mission critical" machine like a HTPC or game machine (such as previously discussed) is not a big deal because in my view, that won't affect the others. However when I update the powerful main Workstation, I try to reuse the parts for some of my "lesser" machines; can't let perfectly good high speed CPU, RAM, and motherboard go to waste.

MEASUREMENTS: SMSL A6 as DAC (Part II)

SMSL A6 Integrated Amp - playing through USB 24/352.8kHz signal. Notice the matte/satin finish of the aluminum case. Probably need to wipe it down once awhile if dusty.

As I mentioned last week with the initial review of the SMSL A6 integrated amp, this is a versatile device. It features an AK4452 DAC first released in 2015 which though not "top of the line", does perform very well with a potential 115dB SNR and is part of the "Velvet Sound Architecture" range of "Premium" DACs. For those keeping track, currently, the flagship DAC from AKM is the AK4497, capable of 5-channels and rated at 128dB SNR; they call this series the "Verita" which competes with the best of the ESS DACs like the ES9038Pro previously discussed in the Oppo Sonica DAC measurements and review. By the way, another claim to fame of the AK4497 is that it has a "volume bypass" mode which allows the DSD data to bypass the internal delta-sigma modulator; a more direct processing path... As usual with new features in otherwise mature technologies, whether this is audibly better is probably up for debate.

Today, what I wanted to test out with the SMSL A6 are the RCA and headphone outputs from this device. As usual, along the way we'll have a peek at jitter results, the antialiasing filter being used, and check out the various inputs - USB compared to the S/PDIF variants of TosLink and coaxial.

REVIEW: SMSL A6 integrated amplifier - Part I: Overview and Subjective Listening (and briefly about USB cables)

SMSL A6 at home in my living room system with Tannoy Mercury Mx2 speakers. Doug MacLeod's Break The Chain (2017, Reference Recordings 24/176.4 downsampled to 88.2kHz, DR16) playing over Logitech Media Server.

For many years, my father's audio system consisted of various CD players, a Sony turntable and vintage pre-amplifiers. This then fed a tube pre-amp which then sent the signal to either a tube-based Onyx SP3 Melody amplifier or vintage solid state Pioneer amplifier to feed his Klipsch Forte speakers which have been cleaned and refurbished with new crossover parts over the years.

In the last 5 years, I've supplemented his system with various DACs for the CD player, and most recently got him a streaming connection with my Logitech Media Server based out of my home server using a Logitech/Squeezebox Touch.

This set-up sounds very good. The classic Klipsch speakers really do throw up a fantastic soundstage, have quite a smooth sonic signature (though a little mellow for my taste), is extremely sensitive, thus easily powered by low-wattage amps.

He has gradually transitioned to almost exclusively digital streaming, finding the convenience indispensable compared to spinning disks (whether of the polycarbonate or vinyl variety). As much as the tube and large integrated amps sound great, over time some of those components have needed maintenance and I figured it would be nice for him to try out something much simpler than manually turning on/off multiple devices every time he wants to hear good sounding audio. Thus, the purchase of the SMSL A6 integrated DAC/amp.

MEASUREMENTS: The AudioQuest Dragonfly Black MQA filter set...

Good movie from the 90's!

Just a quick note while we're doing the MQA blind test!

A few weeks ago I posted on the Dragonfly Black and the MQA filter impulse responses. I noted that based on Måns Rullgård's work, although there are potentially 32 filters available when "Rendering" with upsampling to 192+kHz, I only showed 0-8 in that previous post.

Well, using the same kind of impulse response diagram previously (captured using my Focusrite Forte 24/192 ADC), here's the AudioQuest Dragonfly Black "full monty" of impulses...

INTERNET BLIND TEST: MQA Core Decoding vs. Standard Hi-Res Audio

Introduction:

Well my friends, the time has come... Yes, it's another Internet Blind Test!

As a "more objective" hobbyist blog, within these pages I try to demonstrate facts, figures, and opinions as best I can with the hopes that it educates the typical "audiophile" out there who loves music and wants to at the same time understand the hardware and technologies used in the world of high-fidelity. I do this for fun with the hopes that in time, as a group we can be "more rational", each of us better able to adjudicate what makes sense, what works, and what ultimately has either very little worth or should even be considered worthless "voodoo".

Over the last few years, as you've no doubt noticed, a number of my posts have been looking at MQA and the claims made. I'm not going to rehash much of that here (feel free to start on this page and check out the links at the bottom accumulated over time). As we've come closer to understanding details like the filters used and how the "Rendering" works, there is one very important piece that remains rather nebulous.

This last piece has to do with claims of time domain "de-blurring". The idea that some kind of DSP has been used to affect the sound quality, ultimately "improving the analogue-to-analogue performance" from the studio to one's own DAC output (ostensibly using various techniques including measuring and aligning impulse responses of the devices used in production and playback). How this works is of course proprietary and hidden in the encoding system which we as end-users have no access to.

MEASUREMENTS: MQA Filters on Mytek Brooklyn & Thoughts on USB Doohickeys

Hey folks... It's summer and I'm in and out of town doing a bit of R&R mixed with the day job.

I sent my friend with the Mytek Brooklyn and Fireface ADC a package of the MQA "Render" tagged files for testing. As you can see above, that's what the MQA filters look like with the Mytek Brooklyn serving as "Renderer" for the impulse responses. If you look at the top row, we see that the Brooklyn's standard digital filter at 24/96 is the same as what MQA uses for playing back 96kHz "original" unfolded PCM. This is different from the Dragonfly Black DAC presented a couple weeks back where the standard filter at 24/96 is a much sharper one and would shift to the weaker MQA filter only when it detects the MQA Render tagged data.

MEASUREMENTS: AudioQuest Dragonfly Black 1.5 - PART 2 (On "MQA Rendering")

AudioQuest Dragonfly Black - "rendering" MQA playback. Dragonfly logo turns purplish...

For those keeping track, the story of MQA has slowly evolved over the last few years. Initially, it was supposed to be just a technology incorporated into DACs that would take an encoded file (typically 24/44 or 24/48) and almost "magically" transform this data into the "original" high resolution (equivalent to 24/192+) sound while maintaining standard PCM playback compatibility. This was the case with the first products like the Meridian Explorer 2. Over the years, it appears that concessions have been made. Software decoding rather suddenly was introduced in early 2017 with TIDAL's support for MQA; branded as "MQA Core". At around the same time, DACs were classified as either "MQA Decoders" for components that can handle these 24/44 or 24/48 files start to finish (Meridian, Mytek DACs), and "MQA Renderers" which require the computer software perform initial "unfolding" to high-res samplerates (88 or 96kHz) followed by some kind of final processing to the sound performed by the DAC presumably to allow the sound to be more "accurate" to the studio production, or "authentic" (whatever that means).

With the recent firmware upgrade to version 1.06, the Dragonfly Black DAC now belongs to this latter category of "Renderer". As far as I am aware, it is the first of these kinds of devices to be released without "Decoding" capability.