Article: MQA: A Review of controversies, concerns, and cautions

[mitchco]

@Archimago awesome job as usual man! What blows me away is that it takes music enthusiasts to bring to light not only technical deficiencies, but what effectively amounts to industry collusion. I for one, don't want yet another closed, proprietary file format, regardless of the technical gobbledegook offered by MQA. The software industry I work in has already been through that nonsense 20 years ago and resolved it with the open source initiative.

 

FLAC is a perfectly fine, proven lossless file format and is FREE. As someone that spent 10 years as a recording/mixing engineer, FLAC can absolutely represent the studio master with no loss whatsoever. 

 

@Samuel T Cogley re: the consumer is always right - perhaps audio enthusiasts need to take a page out of the gamer enthusiasts playbook who used social media to boycott the sales of Battlefront 2. Seemed to be very effective.

 

If folks want accurate sound reproduction from end to end, so that the music arriving at your ears matches as closely as possible to the content on the recording, there currently is only one way to do that and that is by using DSP for loudspeaker and room correction. This allows one to match the music waveforms arriving at ones ears to be as close as possible to the music waveforms encoded on the digital media.

 

Again, great article Arch. I am hopeful that music enthusiasts can see MQA for what it really is.

 

 

[mitchco]

Wrt what is audible or not,  I would love to see more of this type of audibility testing in the consumer audio industry:

 

 

The best I could do is around 12 bits of resolution before auditory masking became too much.  The experiment posted is repeatable if anyone would like to try, plus files can be downloaded and listened to.

 

When Archimago and I attended the Vancouver Audio Show to listen to MQA files, we had an expectation that we would be presented with some AB testing, so we could hear the difference, as the system was certainly resolving enough :-) However, there were no comparisons and instead listened to some gobbledegook from the MQA sales rep, then a few nice sounding recordings, but no AB comparisons.

 

Given @Archimago's article, we now know why there are no audibility tests.

[mitchco]

1 hour ago, The Computer Audiophile said:

I had no clue Sam wasn’t his name until a couple years ago. 

 

Achimago isn’t a mystery to those who’ve met him and know him. It’s a mystery to those who could use his real information in unscrupulous ways. 

 

@mitchco  has met him. 

 

 

 

Yes, Arch and I took in the Vancouver Audio Show, listening to MQA files on a super expensive rig, but no AB comparisons. Ironically, there is even a picture of us listening to MQA files in the article linked - LOL! 

Arch has been over to my place for sushi, beverages and having a fun time listening to my stereo. 

 

I can "authenticate" that @Archimago is a real person  

 

It is rather disappointing that this is even a thing. How about the science? The objective tests Archimago (and @mansr) performed are repeatable. I have not seen any shred of objective evidence to show anything wrong with Arch's test procedures or conclusions. Let's put it to the audiophile industry at large (how about it @John_Atkinson) and especially MQA to prove Arch's tests and conclusions are wrong.  Rather than words, lets see some real science! Because, you know https://xkcd.com/54/

[mitchco]

1 hour ago, John_Atkinson said:

 

In my interviews with Bob Stuart, he has told me that the intention is that the analog signal output by the consumer's D/A converter is identical to that output by the mike preamps (in a purist recording) or the mixing console (in a conventional recording).  That the A/D conversion, transmission, storage and D/A conversion be transparent, other than there being an ultrasonic rolloff equivalent to a signal path of a few feet in air. This has been written about in the magazine.

 

 

It is MQA's time-domain behavior, the claimed 'temporal deblurring," that is fundamental to Stuart's explanation. And as I have said before,  that is what I will be investigating in a future article. Up to now, what we have investigated and written about is MQA's  frequency-domain behavior and MQA's societal and commercial aspects. I don't comprehend why you and other posters to CA don't regard that as journalism, investigative or otherwise. Unless you are confusing Stereophile with another magazine?

 

John Atkinson

Editor, Stereophile

 

 

 

Hi John, as an ex 10 year recording/mixing engineer, DSP aficionado, and software engineer by day, I wonder what is the definition of deblurring or temporal deblurring?

 

In the world of DSP,  deblurring is usually associated with digital image restoration that can sharpen an out of focus image for the eyes. The only time I have seen it applied in the audio world is when using digital loudspeaker and room correction DSP. This is where the digital signal of the music file is convolved with a custom digital correction filter, so the music arriving at ones ears matches as closely as possible to the music encoded in the digital media file. There are several articles written about this here on CA.

 

Technically, we are talking 65,536 filters taps which is 2000 more powerful than MQA's 32 taps. Also, digital loudspeaker and room correction DSP corrects the entire signal path (i.e. playback chain) to ones ears, both in the frequency and time domain. As far as I know, currently today, this is the only way to achieve fully accurate sound reproduction where the frequency response is flat along with flat phase response and group delay to ones ears. Note this also corrects a loudspeakers timing response, as some 95% of loudspeakers are not time aligned. What would be the point of MQA deblurring if it can't deblur the loudspeaker? Makes no sense.

 

John, I am a real fan of your measurements and wanted to personally thank you for this, especially your talks on loudspeaker measurements. This is why I am puzzled, and obviously others, as to why you would even entertain such a thing?

 

Kind regards, Mitch

[mitchco]

52 minutes ago, Archimago said:

 

Agree...

 

And I hope for the sake of all that's good left in music production that they still have high quality, uncompressed tracks in the vaults such that some day this could be properly redone free from being a "loudness war" casualty.

 

 

Unfortunately, for rock, pop, blues and most anything not classical, this will not be the case. As an ex-recording/mixing engineer, I can say that tracks are already compressed before even being recorded. Meaning, most mixing consoles have compressors/limiters on every channel strip. More often than not, compression and limiting is applied on the way to the multitrack recorder (analog or digital). More often than not, during mixdown, not only possible on individual tracks, but absolutely on the stereo master bus before hitting tape or digital. Finally, applied again during the mastering process.

 

Speaking with one of the engineers that did the mass majority of HDTracks transfers, more often than not, receives whatever is provided by the publishing company, and more often than not, it is a "safety" master is provided, which is an already compressed mixdown on tape or digital. The best the engineer can do is eq the master and add some stereo processing, depth, maybe add a bit of reverb...

 

Finally, virtually all music has passed through the device before it even reaches your ears. The simple reality is that we have all heard the sound of this device since 1967 – that’s 50 years ago folks. In fact, if you are listening to mainstream music right now, it is likely that you are also listening to the sound of this device. If you look at how the  Universal Audio 1176LN Peak Limiter works, it can substantially alter the music waveform in a way that there is no coming back, regardless of anything MQA can or cannot do.

 

Not to paint the bleakest picture :), the likelihood of uncompressed tracks being in vaults, is about 0. Given the ubiquity of "studios in a box" and access to everyone, proper professional recording, mixing and mastering is becoming (or has become) a lost art...

 

If the consumer audiophile industry wanted to really do something, demanding better recordings, mixes and masters is where we would see real audible sonic improvements. Sorry Arch, did not mean to single you out, just a PSA.

[mitchco]

1 hour ago, Archimago said:

 

Dang Mitch. That's freaking depressing, man! 

 

 

Sorry Arch, probably revealed a little too much on how the sausage is made... I am illustrating how absolutely pointless MQA is, and for that matter most of HDTracks as well. Check this less than 2 minute video out:

 

 

Even with YouTube compression and over crappy laptop speakers, most folks can hear a clear audible difference with uncompressed versus compressed drums.

 

That's the point - MQA does nothing to solve what is easily the most audible problem and scourge of the consumer audiophile industry for the last 25 years, especially if one listens to anything other than classical or jazz on speciality labels.

 

Now had MQA structured a deal with the 3 majors to actually "remaster" from the original multi-track masters and guaranteed that Master Quality Authenticated meant a DR of 10 or greater then take my money!! I would even pay extra! Instead it is some woo about fixing obscure ADC problems that no-one seems to reliably hear even a perceptible audible difference, so ppfffttttt!!!

 

Oh yeah, wait till folks find out about the additional compression/limiting being applied to their streaming audio... ooops. 

[mitchco]

Arch has a nice write-up here on doing just that:

http://archimago.blogspot.ca/2017/08/musings-increasing-dynamic-range-of.html

 

When I was recording, I did my best not to apply compression going to multi-track tape. A lot depends on the musicians being able to play whatever instrument/vocals consistently throughout a song. If you have even been in a band, even a school band from yesteryear, the dynamics go up and down with the flow of the emotion of the music being played. In a studio environment, most artists/bands are surprised how clear and dynamic they sound over headphones and sometimes have a hard time adjusting as small playing changes yield big dynamic changes in volume. So when going to tape and getting a good signal to noise ratio. some players require compression to be able to either not have enough SNR or too much and distort the tape.

 

Every multi-track tape usually had a track sheet that had notes on fader levels, eq, compression, effects, etc., per track, so one could relatively easily reproduce the mix or get real close. Further, most mixing consoles had automation where a number of these parameters are remembered by the computer.

 

That's what I am talking about with respect to "remastering". Not just taking the already mixed two track tape and messing with it. Rather going back to the original 2" multi-track tape or digital and now with modern DSP, meticulously restoring the sound quality to something that sounds like high fidelity and not having the life squashed out of the music due to too mush dynamic range compression. If that (ever) happened, I would be happy to repurchase my entire catalog...