Music in the Round #84: Multichannel MQA Multichannel MQA Again

Multichannel MQA again, from April 2018 (Vol.41 No.4):

"Not MQA again!" I'm sure some of you will say, regardless of where you stand on it. The loud debate is often less about how MQA actually sounds and works than about opinions and, to an alarming degree, charges of dishonesty and bias. While Stereophile's John Atkinson and Jim Austin continue to strive to rise above all that, all I want to know is what value MQA might have for my own enjoyment of music.

This is not my first stab at this: In the May 2017 Stereophile I both recounted my long-ago first exposure to MQA, which predated its naming, and wrote of listening to stereo and multichannel MQA recordings, using three Mytek Brooklyn DACs. In the latter, I concluded that MQA "made a real and consistent improvement" but that "the differences weren't blatant; I couldn't hear them without paying close attention."

In his "Measurements" section accompanying Jason Victor Serinus's review, in the January 2018 Stereophile, of Aurender's A10 caching network music player/server, John Atkinson revealed "the A10's misapplication of the MQA reconstruction filter to non-MQA files stored on its internal drive."

In his comments accompanying Jim Austin's review of the Mytek HiFi Brooklyn DAC in November 2016, John stated that "for MQA, the filter is set to a fixed, minimum-phase, slow-rolloff type," and that to select any other, possibly more suitable filter, "MQA playback must be disabled." That information is printed in the Brooklyn's user's manual, but I missed it. I had presumed that the Brooklyn's detection of the MQA flag in the digital data would switch in the MQA filter automatically, and that in the flag's absence the DAC would revert to the standard PCM/DSD reconstruction filter, much as an FM radio's detection of a subcarrier signal in a station's/broadcaster's signal would turn on the stereo decoder. (Yes, that's how old I am.)

Because the Mytek Brooklyn, by design, dismissed my filter selections, I wasn't making the exact comparisons I thought I was making. Armed with this realization, I wanted to revisit those comparisons to hear if my conclusions would stand.

Playing high-resolution multichannel and CD-quality (16-bit/44.1kHz) stereo tracks, I began by again comparing the Brooklyn's three available reconstruction filters: Fast Rolloff (FR), Slow Rolloff (SR), and Minimum Phase (MPH), the last filter the default when MQA is enabled. With most tracks, the differences were apparent, but which filter I preferred was not consistent from track to track. The most telling differences were in the tonality and presence of solo voices and the perceived spatial relationship of the voice, its accompaniment, and the recording venue. But I've done this kind of thing before, and it's never completely satisfying: all the time and effort spent just reinforces my suspicion that there is no perfect choice. Still, my non-statistical preference was most often for the MPH filter, followed by SR and FR. What this means is that, even if I'd done my homework, I would have chosen MPH. This suggests my previous comparisons are still valid.

I decided to reassess my comparison of MQA (FLAC) with hi-rez (DXD) files by adding a third element: DSD files of the same nine multichannel recordings, all from Norwegian label 2L. As I found before, the MQA files sounded consistently smoother in the treble than the DXD. However, the corresponding DSD files had a smoothness that approached what I heard from MQA. On the other hand, the DSD files had the same spectral balance as the DXDs, while MQA sounded just a bit more forward, particularly in the upper strings. I repeated this three-way comparison many times and MQA generally sounded more open, with greater contrast between the players and the ambience of the recording venue, less noise within the ambience, and more detailed and silky trebles.

MQA was delightful, but its sound differed from the sounds of the DXD and DSD file formats—both of which also came direct from 2L, a proponent of MQA—in quite another way. The more I listened, the more I found the overall balance of DXD and DSD more even, more continuous, and more convincing in multichannel through my system with these tracks, all from the same label. The magnitudes of these differences were very similar to those among the reconstruction filters of the Mytek Brooklyn DAC, or among the mind-spinning seven filters of the Oppo UDP-205 universal Blu-ray player. I wonder if the subjective enhancements I heard from MQA might be obtained from the other two simply by careful selection of the filter from a library of same.

However, if I switched in room/speaker equalization with the DXD and DSD files (now downsampled to 24-bit/192kHz PCM for compatibility with the DSP), all niggling about subtle differences went out the window. I can't say that MQA files played through my system would not equally benefit from room EQ—that's not possible at this time—but whatever felicities MQA offers are dwarfed by the benefits of room EQ. The results from DXD and DSD were now superior in all parameters, including detail, smoothness, and balance, especially through the midbass and lower bass.

Today, I am less enthusiastic about MQA than I was. High-resolution streaming and downloads are now readily available, and the compactness of MQA files does speed downloads and conserve storage space. Storage space is cheap, however, and I stream music only for casual listening. MQA requires the purchase of compatible equipment, and holds the potential to eventually control all signal processing, such as room EQ. I don't see a need for it, therefore, and I hope it doesn't force the elimination of high-resolution, non-MQA downloads (footnote 1).—Kalman Rubinson

Footnote 1: See John Atkinson's "As We See It" in February 2018.

Gumbo2000's picture

Niche: Audiophilia
Micro-niche: MQA
Nano-niche: Multichannel MQA

Kal Rubinson's picture

Granted but it's in such obscure niches where one finds the gems. ;-)

Htnut1975's picture

I wasn't sure i understood the problem with room correction DSP and MQA. If the dac converts prior to sending to a processor or sends the unfolded MQA stream digitally to a processor, and suppose the processor is the unit applying room correction, what would be the issue?

Kal Rubinson's picture

But after the DAC, you have analog. So, in order to do any DSP, you would have to redigitize the signals. As a result, yes, you would have MQA but it is probable that any advantage that may be would be negated by any additional analog-to-digital-to-DSP-to-digital machinations.

mcdiamond's picture

All the USB DAC's were synchronized by WCLK in a daisy chain. How did you checked out, that there is no delay between L/R + C/LFE + SL/SR?

Kal Rubinson's picture

I didn't but I imagine that it is the reason for synchronizing the WCLK. If you suspect that there is a problem with this procedure (I have no reason to believe there is), ask Mytek.

FWIW, I erred, once or twice, in setting the CLK for one of the DACs to "Internal" and the sound was not good.

mcdiamond's picture

There is no doubt about the WLCK interconnection, that the DAC are in sync. Normal consumer OS are not able to give out a proper sync.

The question was about a constant shift between the stereo DAC.
E. g. the L/R could be earlier like the C/LFE and SL/SR are somewhere. You won't recognice it so easily, because there will be no extra distortion. Just the soundfield will be somehow different.
Was there any procedure to do?

Kal Rubinson's picture

Understand that point but there is no procedure involved as far as I know. The L/R DAC generates the CLK which is sent to the C/Sub DAC and then relayed to the SL/SR DAC. I doubt that this is a problem considering that the links were very short and any timing differences would be inordinately less than those caused by speaker placement errors on the sub-millimeter level.

Again, if you are concerned about this, ask Mytek as I am not bothered by it.

roeckj's picture

I really appreciated this column on MQA; I plan now to closely follow its commercial development.

I noticed in Manufacturers' Comments in the hard copy of Stereophile in which your column originally appeared that MQA's Bob Stuart observed that it is technically possible to perform EQ and other DSP in MQA, so I'm hoping that when multichannel MQA enabled units are ultimately sold to the public it will integrate DSP.

Multichannel DSD has the same problem. I am particularly concerned with speaker distance adjustments and bass management being only as good as the "fidelity" of the DSD to PCM conversion mechanics. Have you found a way to handle DSP purely in DSD?

Kal Rubinson's picture

I have not found an effective way to do DSP in DSD but I have also not found any significant disadvantage to DSD-to-PCM conversions.

roeckj's picture

I understand the necessity of DSD to PCM conversion when playing a multichannel SACD. But given the large file sizes, isn't more practical to stick to high resolution PCM multichannel downloads in FLAC, given that it is highly likely that the master was in DSD and the PCM conversion has already been made in the mixing process?

P.S. I really enjoy your Stereophile column; it is the first thing I look for when I open my copy of the magazine.

Kal Rubinson's picture

I am not concerned with the file size and I do not see a consistent advantage for PCM or DSD given the wide range of available resolutions.

Generally, I download in the format and resolution in which the recording was made, if that information is available.

Thanks for your comments.

egsp's picture

I have trouble understanding what the resistance to multi-channel is. Its superiority seems so obvious to me--truly glorious when well-implemented! A real advance in recorded music, IMO.

Thank you for your efforts--it seems like MC might disappear without it. I buy many of your recommended recordings, too. The 2L recordings are incredible!

PeterMrozik's picture

I acquired a copy of Reflections based on your review, and I received it yesterday. I noticed that there are a number of versions of the album in different formats, with different resolutions. It looks like the one to focus on is the 5.1 DTS-HD 24/384 copy, but I also wanted to mention that there is a lower resolution copy mastered (encoded? not certain of the appropriate verb here) in ATMOS, which should be fun to compare.
I also found to my delight that you can extract MQA encoded FLAC files, so I now have a great collection of 24/384 MQA titles to listen to on my MQA capable media player.
Interestingly, these are all on a Blu-Ray Audio disc, but they also include a copy on SACD. May I assume that the SACD version will be inferior to the 5.1 DTS-HD version or would I be in error in thinking that?
I'm very much looking forward to listening to this over the weekend. And it all of a sudden occurs to my why I might want full range speaker for my surround channels, since with this recording there is no "front" orientation, you are truly in the center of the action from what I understand.
Thanks for the recommendation. While I tracked down the winner of the Grammy for Surround recording, I also spotted that Dire Straits "Love Over Gold" is also available, one of my very favorite albums, so one of this is UPS'ing it's way to me at this very moment. Have you heard it? What did/do you think of it?


I listened to Reflections several times this weekend, what a wonderful recording! I settled on listening to the 5.1 DTS-HD version for a full listening, but experimented with the Atmos copy too. Overall, I think the Atmos copy did a slightly better job of the surround placement of instruments, but the lower resolution (96k) was a bit of a drawback when compared to the 384k DTS-HD version. I listened to the stereo MQA tracks on my Pioneer PMP and that sounded just outstanding, even on my lesser bedroom system.
There is also a SACD copy - I wonder, are there any advantages that this version may have that the ones on the Blu-Ray do not?

parnelligq's picture

I need a little advice. what are the best usb cables and hub for HIFI to connect a BlueSound vault to a PC and a DROBO? Any help is much appreciated.