MQA is Vaporware

[esldude]

1 hour ago, crenca said:

 

I have not seen a physics/scientific reading either.  Anyone have a link?  What he says is correct from the perspective of my limited understanding of (the physics behind) sound.  There is only one waveform, as sound is a single composite, "one waveform to rule them all".

 

If you applied a theoretically perfect brick wall low pass filter to say 1khz to a recording of an instrument with a lot HF (yet still in the audible band) overtones (say, a trumpet), the < 1khz sound would still be "correct" or fidelitous because the < 1khz waveform would already have the intermodulation effects "baked in" so to speak.  So recordings (and the playback thereof) of real instruments in real space at least don't need anything other than the audible band - you don't need "super tweeters" and the like to properly reproduce the audible band.  Studio concoctions I believe would also be correct (i.e the intermodulation effects of ultrasonic overtones are already in the audible band) when they are "mixed" - perhaps @esldudeor someone with firsthand knowledge can confirm or deny this.

I don't know that I'm any authority to confirm this. 

 

But yes if an instrument or other sound caused intermodulation into the audible band, microphones will record it.  They have no way to separate intermodulation produced sound from any other sound.  If someone has done some mixing and processing that altered the sound and the reason is intermodulation, they couldn't hear that unless it was in the below 20 khz sound.  20 khz will record it.

 

And think about this.  Suppose the sound levels of some ultrasonics are so high that the non-linearity of the air causes intermodulation into lower frequencies.   And you record it with wideband microphones and reproduce it with wide band speakers capable of playing it back at levels high enough to intermodulate with the air below 20 khz.  You've just doubled the audible intermodulation generated tones vs were you there to hear it live.  In direct comparisons it may have more air, space, growl or zip than 20 khz reproduction only.  But it actually is a distortion to produce those frequencies.  You could only hear 20 khz if you were there live. 

 

A British company some 15 or so years ago promised to make speakers on the principle.  I think it was going to run ultrasonic emitters at 60 khz and vary them so it would intermodulate thru the air and produce sound in the below 20 khz band.  It apparently had hurdles that couldn't be fully over come.  Dr. Joseph Pompei once of MIT and now of Audio Spotlight has worked on this.  The advantage is you could fire two emitters at a distant location and have the beams intermodulate or demodulate into the audible band at a distant location.  You could make it sound as if the sound were right beside someone at a distance. For such to work at all sound levels have to be above 100 db SPL for the air to be non-linear enough.  

 

https://www.holosonics.com/product-brochure-pdf

 

https://engineering.dartmouth.edu/events/the-audio-spotlight-beams-of-sound-from-ultrasound/

[mansr]

7 hours ago, esldude said:

But yes if an instrument or other sound caused intermodulation into the audible band, microphones will record it.

Unless there is intermodulation occurring within our ears. Anything happening outside our ears will obviously be captured by a microphone.

[Kal Rubinson]

3 hours ago, mansr said:

Unless there is intermodulation occurring within our ears. Anything happening outside our ears will obviously be captured by a microphone.

And that was my original point.  

[mansr]

1 minute ago, Kal Rubinson said:

And that was my original point.  

People have a phenomenal knack for ignoring the point and arguing endlessly against something else entirely.

[Jud]

I do sometimes wonder whether a liking for audio that has spurious ultrasonics, such as MQA, is due to our missing some slight level of ultrasonics in live sound, however we may sense the presence of them (bone conduction, ...?).

 

As I say, it's something I'm occasionally curious about, not anything I'm contending is necessarily significant or real.

[John Dyson]

15 hours ago, sandyk said:

 

 Sorry John, but highly experienced Recording and Mastering Engineers such as Barry Diament who these days only records in 24/192 .aiff with GENUINE musical content to >55kHz do NOT agree with you.

He finds that recording at  24/192 gets him to virtually identical to what his mic feed sounds like.

Recording at 16/44.1 doesn't even get close for Barry.

 

Regards

Alex

But -- when there is music at that frequency (when there is) -- you cannot hear it unless you start getting into the high SPL levels -- then other problems ensue.  It is a ZERO win for distributing material above 20kHz or so.  (I am NOT saying relgiously at 20kHz -- just that the cost/benefit drops rapidly.)

BTW -- it is okay for 'experts'  to be wrong all of the time...  That is okay -- but I am correct about the 20kHz thing.  Also, the 'splat' thing is certainly dependent on the situation...  You are speaking wtih Barry that he is using a pristine internal/professional recording source.  For distribution -- lots of nonsense gets mixed in.  I look at all kinds of distributions that get to the consumers -- The same material/different distributions  have different distortions/ control tones/etc.

 

Geesh -- I can create a test tone just as high in frequency as anyone else, but above about 18kHz (21-22kHz in some very special people), it cannot be heard.  Don't even bring in the idea of transients -- that has nothing to do with it -- unless the SPL is powdering you.

Note that I am a 40yr EE/Computer (EE Analog, all kinds of computer, degree in EE -- not technologist) person from Bell Labs, on the other hand -- a recording technologist knows his world -- that is okay, but what I am telling you is a physical true engineering fact (not only as a technologist -- user of equipment.)

 

You are comparing Barry's (or whoever my daddy is bigger than your daddy expernt) LAB experience with real world material that is sold to consumers -- different things.   The splats are almost IMPOSSIBLE to distinguish from pure material -- and in fact the splats might LOOK nicer, but they are wrong.   (Actually, I do believe that I can seperate some of the splat energy from the signal -- the DHNRDS decoder does that, but it all depends on the circumstance.)

Barry can generate a 100k test tone, then I can generate a 101k test tone -- got the idea? 

 

John

[Rt66indierock]

3 hours ago, Jud said:

I do sometimes wonder whether a liking for audio that has spurious ultrasonics, such as MQA, is due to our missing some slight level of ultrasonics in live sound, however we may sense the presence of them (bone conduction, ...?).

 

As I say, it's something I'm occasionally curious about, not anything I'm contending is necessarily significant or real.

 

I've said more than a few times I can detect ultrasonics from a crash cymbal when I'm hitting it (bone conduction probably). But I can't detect them listening 10 feet away. But then Richard Vandersteen considers my hearing abilities "lucky." 

[John Dyson]

OMG -- sorry about replying to my own post -- but regarding 'splats' which happen *to some degree* on almost any automatic gain control device.   The splat (IMD) characteristics depend on both the gain control mechnaism and the signal.

 

I got some very encouraging results with the DHNRDS decoder WRT 'splats' (haven't checked in a few weeks) - doing ANY DolbyA processing on the old HW, encoding or decoding, will produce IMD splats across the audio spectrum -- even without extreme transients in the audio.  (The effect is paradoxically a softening/fuzzing of the sound.)  

 

My DHNRDS measurement show ZERO measurable splats in the ever so important higher audio frequencies, even where they could happen.  This very nice observation does NOT utilize the absolute IMD avoidance of band splitting... 

Band splitting: the DA decoder splits the audio band up so that the audible below 20kHz doesn't create splats into the super-audio range, and the super-audio range cannot create IMD that drops into the audio range.

 

Additionally on the DHNRDS DA -- recently made some trajectory shaping improvements -- even below 20kHz, on pretty intense material, I can not measure any IMD splats above 14kHz when simply bandlimiting the input audio below 14kHz on the input.  This shows that the IMD control is really good.*

* This means that even without the band splitting, the IMD is very substantially (seems like completely) suppressed.   I know that it isn't really 100% suppressed, but it is created and put in a different -- less audiblle -- place.

 

What is a 'SPLAT'? (my nomenclature, not standardized)  It is a burst of intermodulation energy that often comes from gain control changes being mixed with th audio.   A 'SPLAT' can actually be any kind of intermodulation energy -- sometimes looking just like a cymbal crash encroaching into and beyond 20kHz frequency range.

 

Normally, with the fast/relatively ragged DolbyA attack/release, you'll get splats as strong as any normal audio above 20kHz -- with a slow RMS style compressor, the splats still happen -- but are of lower magnitude.

So, generally, a fast fet-style limiter will tend to produce splats more easily (unless very carefully designed) than a smooth RMS compressor...  The DolbyA technology is almost  a worst case of a fast FET-style compressor that doesn't explicitly clip the audio.  (DolbyA could be worse than it is/was, but R Dolby was a brilliant engineer/researcher, and did an excellent job with the technology that he had.)

[John Dyson]

13 minutes ago, Rt66indierock said:

 

I've said more than a few times I can detect ultrasonics from a crash cymbal when I'm hitting it (bone conduction probably). But I can't detect them listening 10 feet away. But then Richard Vandersteen considers my hearing abilities "lucky." 

Deep in my past memories -- I do seem to remember that bone conduction does have wider HF bandwidth than 'hearing'.  I know nothing about the actual mechanism (one can always guess) -- but your possible implication about bone conduction did wake up that stale/old memory.  It might be proven wrong, but I'd guess that you are actually manifesting the bone conduction that the old papers spoke of (I mean decades-old papers.)

 

John

[Rt66indierock]

1 minute ago, John Dyson said:

Deep in my past memories -- I do seem to remember that bone conduction does have wider HF bandwidth than 'hearing'.  I know nothing about the actual mechanism (one can always guess) -- but your possible implication about bone conduction did wake up that stale/old memory.  It might be proven wrong, but I'd guess that you are actually manifesting the bone conduction that the old papers spoke of (I mean decades-old papers.)

 

John

 

John, I noted it with an all hands on deck situation (a dam breach) which had me welding for a couple days as well. I did not find either case a feeling I wanted to repeat. 

 

Speaking of memory I remember something about needing high sound pressure levels to transmit ultrasonics through the air any distance but I can't seem to remember the source.

[lucretius]

18 minutes ago, John Dyson said:

R Dolby was a brilliant engineer/researcher, and did an excellent job with the technology that he had.

 

Off-topic.

 

I see Dolby had 2 academy awards and a star on the Hollywood Walk of Fame. How many engineers can say that?

[Ralf11]

https://www.ncbi.nlm.nih.gov/pubmed/23384569

[The Computer Audiophile]

6 minutes ago, Ralf11 said:

https://www.ncbi.nlm.nih.gov/pubmed/23384569

I can see it now:

 

"Ultrasound can be perceived"

- Audiophile Press

[pkane2001]

9 minutes ago, The Computer Audiophile said:

I can see it now:

 

"Ultrasound can be perceived"

- Audiophile Press

 

All one needs to do is stick a tweeter inside the ear and sit on a subwoofer

 

[james45974]

46 minutes ago, Ralf11 said:

https://www.ncbi.nlm.nih.gov/pubmed/23384569

I think I get the general gist of the paper but can someone translate the results for post radiation for a non-scientific mind such as my own!  Thanks! ☺️

[Rt66indierock]

43 minutes ago, The Computer Audiophile said:

I can see it now:

 

"Ultrasound can be perceived"

- Audiophile Press

 

Haven't I said this under a couple of conditions? Hitting a crash cymbal and some types of welding but when can't it be perceived? In my case 10 feet away.

[Jud]

1 hour ago, Rt66indierock said:

 

Haven't I said this under a couple of conditions? Hitting a crash cymbal and some types of welding but when can't it be perceived? In my case 10 feet away.

 

When dealing with a close-miked production, I wonder whether we subconsciously feel there ought to be ultrasonics if we're (audio-wise) within a foot or two of the instrument, so that our cues are messed up relative to what we'd be hearing in that situation live. Again, just complete speculation, wondering why at least a portion of the audience apparently likes spurious ultrasonics.

[Jud]

2 hours ago, The Computer Audiophile said:

I can see it now:

 

"Ultrasound can be perceived"

- Audiophile Press

 

On a more serious note, bone conduction, including ultrasonics, is involved in some research regarding assisting the deaf to perceive sound.

[Rt66indierock]

17 minutes ago, Jud said:

 

When dealing with a close-miked production, I wonder whether we subconsciously feel there ought to be ultrasonics if we're (audio-wise) within a foot or two of the instrument, so that our cues are messed up relative to what we'd be hearing in that situation live. Again, just complete speculation, wondering why at least a portion of the audience apparently likes spurious ultrasonics.

 

Jud, I was going to post that some people like the distortion ultrasonics cause. The pro guys have been wondering about this for more than a decade.  I received a thread going back a long time this morning as part of a weekly update. And at t.h.e. Show we talked a bit about the artifacts created by large amounts of empty space in a 24/192 file.

[Ralf11]

mix some in and do a listening test

[mansr]

5 minutes ago, Rt66indierock said:

the artifacts created by large amounts of empty space in a 24/192 file.

What now?

[sandyk]

5 hours ago, John Dyson said:

 

You are comparing Barry's (or whoever my daddy is bigger than your daddy expernt) LAB experience with real world material that is sold to consumers -- different things. 

 

Hi John

Barry's 24/192 material IS sold to consumers.

 I think that we should agree to disagree on the merits of high res LPCM or DSD, as there are a large percentage  of members and people world wide who love those formats and prefer them over RBCD for whatever reasons, including a less abrupt roll off of frequencies above 22kHz.

It seems highly likely that we have yet to discover the definitive reasons why many people have this preference.

There is obviously some reason that they do, and in fact our member Teresa , before Alzheimers afflicted her, found something about RBCD that annoyed her, yet high res material including DSD did not.

I seriously doubt that it came down to the poor design of her source either.

 

Kind Regards

Alex

[sandyk]

8 hours ago, Jud said:

I do sometimes wonder whether a liking for audio that has spurious ultrasonics, such as MQA, is due to our missing some slight level of ultrasonics in live sound, however we may sense the presence of them (bone conduction, ...?).

 Hi Jud

 You forgot to mention SACD along with MQA

 

Kind Regards

Alex

[daverich4]

21 hours ago, sandyk said:

 

 Sorry John, but highly experienced Recording and Mastering Engineers such as Barry Diament 

 

Its been apparent for some time now that you use Barry Diament as some type of shield, waving him around to protect yourself from opinions different from your own. Don’t you know anyone else?

[sandyk]

3 minutes ago, daverich4 said:

 

Its been apparent for some time now that you use Barry Diament as some type of shield, waving him around to protect yourself from opinions different from your own. Don’t you know anyone else?

 

Would you prefer that I kept bringing up Martin Colloms and the increasing number of A.S members that have already verified my main reports ?  There are now several highly respected, and high profile qualified members among them.

It's not my fault if you, and a core group of members, are unwilling to even investigate the proof that I have offered to make available on numerous occasions, as well as the material that is available in My Profile.