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  • esldude
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Meridian Audio's new... sub-format called MQA.
Reply #25
I also wonder does this new format do anything high sample rate Ogg Vorbis wouldn't accomplish?  It will give somewhere around a 4 to 1 reduction in file size while maintaining bandwidth at highest quality settings.  If you used your own filter at something like 30 khz just to be sure you can knock down the file size by another factor of two or three.  Not that I believe we need the extra bandwidth myself.
  • Last Edit: 05 December, 2014, 04:46:23 PM by esldude

  • mzil
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Meridian Audio's new... sub-format called MQA.
Reply #26
According to this Meridian graph I should stick to my Studer tape recorder, if I can live with its low convenience level. 
The most startling one to me is LPs being said to be better than CD. Since CD is better in terms of rotational wow, warp wow, flutter, speed accuracy, hiss, dynamic range, hum, crackle, skips, pops/ticks, frequency response deviation, distortion, groove wear, inner groove distortion, channel separation, etc., I wonder what specific audio parameter they deem more important than all of these so as to give LP the edge by >2 "units" of quality?
  • Last Edit: 05 December, 2014, 06:08:40 PM by mzil

  • greynol
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Meridian Audio's new... sub-format called MQA.
Reply #27
Maybe if they don't say vinyl is better than CD they'll lose cred with their intended customer base.
Is 24-bit/192kHz good enough for your lo-fi vinyl, or do you need 32/384?

  • MLXXX
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Meridian Audio's new... sub-format called MQA.
Reply #28
When I saw that quality/convenience graph I nearly wept.

I felt a wave of nausea, and then sadness. To see such a bizarre graph being published in 2014 is quite saddening.

The most startling one to me is LPs being said to be better than CD. Since CD is better in terms of rotational wow, warp wow, flutter, speed accuracy, hiss, dynamic range, hum, crackle, skips, pops/ticks, frequency response deviation, distortion, groove wear, inner groove distortion, channel separation, etc., I wonder what specific audio parameter they deem more important than all of these so as to give LP the edge by >2 "units" of quality?

Well, CDs involve sampled audio, don't you know, rather than recording the wave continuously in a "proper analogue way". Not convinced? Ok, here's a specific: vinyl can be operated further into the ultrasonic realm than CDs, theoretically. (That's of highly questionable value of course.) I think it boils down to greynol's point immediately above.

There's a certain percentage of audiophiles who have been "educated" to believe that the standard CD format is inferior, and who are accordingly looking for an improvement over CD sound.

Maybe if they don't say vinyl is better than CD they'll lose cred with their intended customer base.

Ah yes, good point.

  • greynol
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Meridian Audio's new... sub-format called MQA.
Reply #29
...and to your point, it doesn't help to push something as just an incremental improvement over 30 year old technology;

an incremental improvement that requires going to extraordinary and dubious lengths just to show a tepidly noticeable difference.
  • Last Edit: 05 December, 2014, 10:43:29 PM by greynol
Is 24-bit/192kHz good enough for your lo-fi vinyl, or do you need 32/384?

Meridian Audio's new... sub-format called MQA.
Reply #30
Depressing.
FLAC -> JDS Labs ODAC/O2 -> Sennheiser HD 650 (equalized)

Meridian Audio's new... sub-format called MQA.
Reply #31
Maybe if they don't say vinyl is better than CD they'll lose cred with their intended customer base.
Don't forget that Meridian has to explain why it's safe to use digital speakers, even when listening to vinyl or reel to reel.

  • Porcus
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Meridian Audio's new... sub-format called MQA.
Reply #32
Yeah, Meridian did early go digital-only - I use their speakers BTW, with a cheap USB-to-SPDIF between them and fb2k.
I do not understand why they want to present this mumbojumbo, it just doesn't fit someone who used to promote a fully digital reproduction line.

That reel-to-reel is "better" is in some sense justifiable from the point of view that most likely that is the original source. It is of course grossly inconvenient to remaster the album every time you need to listen to it, but it is not unlikely better than the DR = 3 CD

  • Porcus
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Meridian Audio's new... sub-format called MQA.
Reply #33
I wonder:

- would a "Dirac" - which, I figure, must be an energy discontinuity, i.e. an infinitely loud infinitely short spike or something practically very close - be anything you wanted to feed into your playback equipment?

- assuming it would be reproduced: would you want to feed it into your ears?

  • adamdea
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Meridian Audio's new... sub-format called MQA.
Reply #34
I wonder:

- would a "Dirac" - which, I figure, must be an energy discontinuity, i.e. an infinitely loud infinitely short spike or something practically very close - be anything you wanted to feed into your playback equipment?

- assuming it would be reproduced: would you want to feed it into your ears?

Very good point. Even ignoring the idea that it requires all of the energy in the universe (which is how it was explained to me) I'm not sure I understand what it means in sound terms though. After all we are supposed to be talking about recorded sound here not x rays

Surely in order to be a dirac, the air molecules would have to move to one side and then stay there. If they do any compressing and uncompressing then the event would not be a dirac any longer. Is there not an inevitably finite rise time for a sound wave. No idea what is might be though. Any ideas? My intuitive instinct was that it might have something to do with the speed of sound. (don't hit me)

Meridian Audio's new... sub-format called MQA.
Reply #35

This may be based on the ideas revealed in a recent AES paper...
http://www.hydrogenaud.io/forums/index.php...mp;#entry882550

When I saw that quality/convenience graph I nearly wept. I assume it means studio quality reel-to-reel machines running at 15 or 30ips with professional tape stock, not the 7.5ips rubbish sold to consumers in the 1960s, but even so...

Cheers,
David.


Do you mean this paper.
http://www.aes.org/e-lib/browse.cfm?elib=17501

I stumped uo the $20 and downloaded it. I have to confess that I found it very confusing.  I have only an enthusiasitc amateur understanding of sampling based on the standard  undergraduate texts, but I have to say I found bits of it very difficult to follow, especailly the stuff about time blur. Also the explanantion of the limitation of time resolution using inter sample diracs seemed very odd. Obviously Staurt and Craven are clever and expert, and the paper was peer reviewed.


Conference paper, not a journal paper.

Quote
But somehow talking about trasnients which start and finish between samples (as opposed to locatign the peak of an event) seemed a bit dubious to me.


In general there is nothing special about an event starting on sample boundaries. 

Quote
Do these exist in music, or in the world?(assuming 44khz sample rate)


In general they don't exist.

(1) Everything in the real world that we interact with has been subject to any number of low pass filters.

(2) In the world of audio the rule of low pass filtering is especially relevant to musical instruments and microphones. But most real world audio gear has builtin low pass filters starting as low as 15 KHz (FM Stereo) 22 KHz (44 KHz sampled audio) 50 -100 KHz - (most analog gear).

Quote
Isn't an analysis of sampling a dirac "against the law" as it is of course not band-limited?


One might think...

Quote
"Can a sampled system convey time differences that are
shorter than the periods between successive samples? An
intuitive answer might be ‘no’ [60], but we note that even
when convolved with a sinc function, an arbitrarily small
displacement of an impulse can be detecof waveform comparison, assuming one has sufficient
signal-to-noise ratio.
Instantaneous sampling without any filtering is not
recommended, for the sampling would then be vulnerable
to high-frequency noise (even to the megahertz region).

Further, a Dirac impulse would not be registered at all if
it happened to occur between the sampling instants.
Intuitively one would at least integrate over one sample
period, as illustrated in Figure 11 (upper). Here a
transient falling entirely within the sample period
corresponding to Sample 0 will be integrated and the
value of Sample 0 will represent the area of the transient

If the transient moves to the right, there will be no change
in the sample values until the transient crosses into the
adjacent territory of Sample 1. Positional information
has been lost, indeed quantized, so the above ‘intuitive’
answer was correct for this case.

The information loss can be avoided by using an
integration kernel in the form of a triangle or dual ramp
that spans two sample periods, as shown in Figure 11
(lower). By comparing the values of Sample 0 and
Sample 1, both the area and the position of the transient
can now be unambiguously determined."

Can someone explain to me where they are going with this?


Out of the known world. ;-)

  • knucklehead
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Meridian Audio's new... sub-format called MQA.
Reply #36
This may be based on the ideas revealed in a recent AES paper...
http://www.hydrogenaud.io/forums/index.php...mp;#entry882550


When I saw that quality/convenience graph I nearly wept. I assume it means studio quality reel-to-reel machines running at 15 or 30ips with professional tape stock, not the 7.5ips rubbish sold to consumers in the 1960s, but even so...

Cheers,
David.
Do you mean this paper.
http://www.aes.org/e-lib/browse.cfm?elib=17501

I stumped uo the $20 and downloaded it. I have to confess that I found it very confusing.  I have only an enthusiasitc amateur understanding of sampling based on the standard  undergraduate texts, but I have to say I found bits of it very difficult to follow, especailly the stuff about time blur. Also the explanantion of the limitation of time resolution using inter sample diracs seemed very odd. Obviously Staurt and Craven are clever and expert, and the paper was peer reviewed. But somehow talking about trasnients which start and finish between samples (as opposed to locatign the peak of an event) seemed a bit dubious to me. Do these exist in music, or in the world?(assuming 44khz sample rate) Isn't an analysis of sampling a dirac "against the law" as it is of course not band-limited?

"Can a sampled system convey time differences that are
shorter than the periods between successive samples? An
intuitive answer might be ‘no’ [60], but we note that even
when convolved with a sinc function, an arbitrarily small
displacement of an impulse can be detecof waveform comparison, assuming one has sufficient
signal-to-noise ratio.
Instantaneous sampling without any filtering is not
recommended, for the sampling would then be vulnerable
to high-frequency noise (even to the megahertz region).

Further, a Dirac impulse would not be registered at all if
it happened to occur between the sampling instants.
Intuitively one would at least integrate over one sample
period, as illustrated in Figure 11 (upper). Here a
transient falling entirely within the sample period
corresponding to Sample 0 will be integrated and the
value of Sample 0 will represent the area of the transient

If the transient moves to the right, there will be no change
in the sample values until the transient crosses into the
adjacent territory of Sample 1. Positional information
has been lost, indeed quantized, so the above ‘intuitive’
answer was correct for this case.

The information loss can be avoided by using an
integration kernel in the form of a triangle or dual ramp
that spans two sample periods, as shown in Figure 11
(lower). By comparing the values of Sample 0 and
Sample 1, both the area and the position of the transient
can now be unambiguously determined."

Can someone explain to me where they are going with this?


I'll take a guess. 

This is how they will market this as the first digital music that doesn't "sound digital".

Alongside the nice Convenience/Quality graph will be another stair step digital waveform graph.

"See" how digital sounds?
I mean .... just look at the graph!
MQA has the ability to measure between the digital steps and capture that missing emotion.
Finally you can have all the convenience of digital files with all the quality of reel to reel.

... or something like that  ...

  • Porcus
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Meridian Audio's new... sub-format called MQA.
Reply #37
I wonder:

- would a "Dirac" - which, I figure, must be an energy discontinuity, i.e. an infinitely loud infinitely short spike or something practically very close - be anything you wanted to feed into your playback equipment?

- assuming it would be reproduced: would you want to feed it into your ears?

Very good point. Even ignoring the idea that it requires all of the energy in the universe (which is how it was explained to me)


I have not seen the definitions, but I think they mean it only requires infinite power - over zero time. That is, if an amp delivers 1 watt continuously - meaning 1 J per second - this signal added would mean that e.g. precisely at 30.000004 seconds , the total energy dissipated since the start, jumps abruptly from 30.000004 to 30.000104 and then goes on 1 J / second so that at 31 seconds it has delivered 31.0001 joules. This jump would correspond to "infinite" frequency and would therefore not be captured adequately by an ADC nor digital formats. I would be surprised though, if it could be played back on any music equipment (could air actually take such a waveform?).

Now. What if this discontinuity occurs once every 1/100 second? Is it then a 100 Hz tone? Is it sampleable? Is it possible to reproduce with amps and speakers? Will the human ear detect it? Does it even exist?


(My gut feeling says that someone was first and foremost looking for a signal that won't be encoded to a digital format by an ADC, and any question regarding usefulness of the example (like e.g. "does such one even exist on planet Earth?" was of secondary importance.)

  • krabapple
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Meridian Audio's new... sub-format called MQA.
Reply #38
http://hiddenwires.co.uk/2014/meridian-aud...technology-mqa/


Quote
Meridian Audio Launches New Audio Technology: MQA
09/12/2014
Bob Stuart, founder of Meridian Audio, recently launched MQA (Master Quality Authenticated), a new British technology, which the company says “is poised to change the way people enjoy music all over the world”. The launch, hosted in The Shard, was attended by key music industry executives, artists and commentators.

Developed by Meridian as a way of combating what the company sees as the trend of sacrificing sound quality for convenience, MQA is said to capture and preserve nuances and vital information that current music files obscure or discard, but in a file that is small and convenient to download or stream.

“Music lovers need no longer be shortchanged; finally we can all hear exactly what the musicians recorded,” says Bob Stuart, the pioneer behind MQA technology. “MQA gives a clear, accurate and authentic path from the recording studio all the way to any listening environment—at home, in the car or on the go. And we didn’t sacrifice convenience.”

Stuart also advises that “the announcement of MQA is really about the future of recorded music. Music is important to us all. When the sound is authentic it is more involving, we understand it better and enjoy it longer. MQA is already receiving broad support from the music industry, artists, recording and mastering engineers and record labels.

MQA will be available early 2015.
  • Last Edit: 09 December, 2014, 02:58:30 PM by krabapple

  • Woodinville
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Meridian Audio's new... sub-format called MQA.
Reply #39
I have to confess that I found it very confusing.

From reading your quote of the paper I'm also confused.

If you properly lowpass a signal which contains an "inter sample dirac", wouldn't this dirac ripple out into the neighboring samples in the form of a sinc? No need for any other magic. Correct?



Correct.

Manners requires that I do not speak plainly of what I see elsewhere in this thread.
-----
J. D. (jj) Johnston

  • Woodinville
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Meridian Audio's new... sub-format called MQA.
Reply #40
That is my understanding- at least that it would spread out -after all a band limited signal cannot be time limited- but the shape of the remaining signal would I suppose depend on the filter. Then again I am not an expert.


While that's true, one can assure that the spectral content outside of the passband can be reduced to any arbitrary level, in particular one can assure that the contributions from outside the passband are smaller than the quanitzation noise.
-----
J. D. (jj) Johnston

  • Woodinville
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Meridian Audio's new... sub-format called MQA.
Reply #41
Well, CDs involve sampled audio, don't you know, rather than recording the wave continuously in a "proper analogue way". Not convinced? Ok, here's a specific: vinyl can be operated further into the ultrasonic realm than CDs, theoretically. (That's of highly questionable value of course.) I think it boils down to greynol's point immediately above.


CD's also fail to have a variety of euphonic distortion mechanisms. 'nuff said?
-----
J. D. (jj) Johnston

  • krabapple
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Meridian Audio's new... sub-format called MQA.
Reply #42
And right on schedule, lookit what the hi-rez cheerleaders are claiming (or claiming that Meridian claims).  Another *vast improvement*!:

Quote
When an MQA-encoded recording is played back through a consumer-audio product with MQA decoding, the result is, according to Meridian, a vast improvement in sound quality over even the highest-resolution formats extant.
  - Robert Harley, TAS


http://www.theabsolutesound.com/articles/r...o-meridian-mqa/

  • Last Edit: 10 December, 2014, 11:39:52 AM by krabapple

  • lithopsian
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Meridian Audio's new... sub-format called MQA.
Reply #43
Of course you know Robert Hartley is just full of it when he writes stuff like this:
Quote
The treble was totally unlike any other digital I’d heard, completely free from the metallic hardness and artifacts we assume are part-and-parcel of digital audio.

Hard to take anything in the article seriously, but it does give hints at what MQA actually is, although really much more about Meridian's marketing slant.

  • Porcus
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Meridian Audio's new... sub-format called MQA.
Reply #44
You should have put the emph on according to Meridian ... journalism schmournalism.

According to me your happiness in life will increase if you transfer big bucks to my account.

  • adamdea
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Meridian Audio's new... sub-format called MQA.
Reply #45


If you properly lowpass a signal which contains an "inter sample dirac", wouldn't this dirac ripple out into the neighboring samples in the form of a sinc? No need for any other magic. Correct?



Correct.

Manners requires that I do not speak plainly of what I see elsewhere in this thread.

Thanks. Could you help with the question of whether there is a minimum period of a sonic event (at a particular place) in air. I simply can't get my mind round how a dirac (or anything like a dirac) could be produced by the propagation of sound in air. Or am I wrong in imagining that air must vibrate for a while when a pressure wave passes through it.

My anxiety on this subject is caused by the idea that we might for some reason need to be able to locate the leading edge of  a sonic event with greater precision than 16/44 or even 24/96 (conventionally filtered) will allow. I understand that 16/44 allows something like 60 ps of resolution in terms of locating an intersample peak of an  event extending across sampling instants but Stuart and Craven seem to know this and yet for some reason still insist that we migth need to be able to locate an event which rises to a peak from nothing imbetween samples. This sounds suspiciously like something you can't hear to me, but I'm just trying to understand what this might mean in relation to a real world transient

I have been trying to find a recording of a short sound event. I think Bob Stuart mentions twigs snapping somewhere.
I managed to find this recording but I think its only at 32000 khz 
http://soundbible.com/48-Branch-Break.html
Still snapping seems to take a long time to form -at least 2 ms for the main hump (if that's the right way to describe it) and ignoring the  longer build up from scratch. I can see though that this seems to be band limited to about 11 and a bit Khz, but even then it doesn't seem to me that this event could have slipped through the net if it weren't band limited. Nevertheless it would be useful to see a higher sample rate recording to understand how the time domain representation of this event would have differed. I'm simply trying to understand why according to Stuart and Craven my perception of the timing of the event would be different

Perhaps the castanets here would be a better example as they seem to have been sampled at 44.1Khz
http://www.scalatech.co.uk/bsac.htm
Even here though I can't see how the sound could have fitted imbetween two samples if it had not been low pass filtered. 

I find it frustrating that  in Stuart's paper supposedly explaining the time domain requirement for >44khz sampling and the problems of a conventional anti alias filter at 48khz or so he nevr shows a real world time domain illustration of the "time blur" on a real world sonic event explaining the different times at which we will (according to the theory) perceive the sonic event at 44.1 , 96khz with an ordinary filter and 96Khz with the magic filter.
  • Last Edit: 10 December, 2014, 01:44:39 PM by adamdea

  • 2Bdecided
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Meridian Audio's new... sub-format called MQA.
Reply #46
Stuart is proposing a theory. It could be proven or disproven in a rigorous psychoacoustic experiment, but to my knowledge no such experiment has been performed. His recent paper is not proof. It contains too many other variables.

In showing the impulse response of the filter, the paper is pretty much showing you what will happen at the leading edge of any wide bandwidth sharp transient. The waveform changes significantly, but all that horrible looking stuff is at 22kHz.

Cheers,
David.

  • greynol
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Meridian Audio's new... sub-format called MQA.
Reply #47
the paper is pretty much showing you what will happen at the leading edge of any wide bandwidth sharp transient. The waveform changes significantly, but all that horrible looking stuff is at 22kHz.

http://www.hydrogenaud.io/forums/index.php...st&p=880450
Is 24-bit/192kHz good enough for your lo-fi vinyl, or do you need 32/384?

  • krabapple
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Meridian Audio's new... sub-format called MQA.
Reply #48
Of course you know Robert Hartley is just full of it when he writes stuff like this:
Quote
The treble was totally unlike any other digital I’d heard, completely free from the metallic hardness and artifacts we assume are part-and-parcel of digital audio.

Hard to take anything in the article seriously, but it does give hints at what MQA actually is, although really much more about Meridian's marketing slant.


the technical aspects are described in the other AES convention paper, "A Hierarchical Approach to Archiving and Distribution"

http://www.aes.org/e-lib/browse.cfm?elib=17501


NB there are a lot of 'could bes' and 'can bes' and even a 'we imagine' in that paper.
  • Last Edit: 10 December, 2014, 08:31:41 PM by krabapple

  • krabapple
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Meridian Audio's new... sub-format called MQA.
Reply #49
You should have put the emph on according to Meridian ... journalism schmournalism.

According to me your happiness in life will increase if you transfer big bucks to my account.



To be fair, I have not seen any quotes so far directly from Meridian or Stuart that use that phrase 'vast improvement'.  I've only seen it in Harley's article.


But I haven't looked very hard either.