DolbyA decoding feedback -- 'feral' examples (yes/no)

[sandyk]

Quote

So you've got a good handle on what Michael Tretow was after, then?  fas42

 

We could safely bet that what he heard through his monitors when reviewing the session didn't sound remotely like what you hear through restricted frequency range laptop speakers.

 I don't agree with the wording of the image, but many Laptop speakers are no netter than this, with some even worse, and most not even matched as a pair.

[John Dyson]

3 hours ago, fas42 said:

'Fraid I like "crummy", "foggy" sound, John  - the qualities that make ABBA special are significantly reduced in the nofog versions, and especially the lilt in the voices has been lost to an unacceptable degree - I won't be a customer, sorry.

Well, you are indicating that you like 'modulation distortion', which is a bit different from 'intermodulation distortion'.   Perhaps that difference shows an inferiority of the listening equipement, because the 'modulation distortion' does support more opportunities for the 'intermodulation distortion' to occur in poor quality equipment.  IMD is much uglier.   MD can sometimes sound like compression, but is an unintended side defect of DolbyA compression/expansion.  It happens in DolbyA because of the delays in the feedback loop for the inverse compression (expansion) mechanism.

 

I cannot really comment on a preference for an apparent lack of detail -- maybe too complex for the equipment (either wetware or electromechanical, or both?)

 

John

 

[John Dyson]

2 hours ago, sandyk said:

 

We could safely bet that what he heard through his monitors when reviewing the session didn't sound remotely like what you hear through restricted frequency range laptop speakers.

 I don't agree with the wording of the image, but many Laptop speakers are no netter than this, with some even worse, and most not even matched as a pair.

That very limited response (looks like about 6kHz on the high side) with associate temporal distortions don't really allow for any kind of temporal precision in the transmission of the audio.  Also, with the cut at about 200Hz-300Hz (assuming the log scale), the lower MF ambiance will be materially affected.

 

Even worse, lots of MD (where MD temporally fogs the signal), perhaps even smoothing it out a bit -- will mitgate some of the IMD in cheap/poor quality equiment.   Oddly, even though the DHNRDS has greater temporal detail, it produces fewer errant peaks than a true DolbyA*, thereby allowing a louder (fewer of the evil peaks that mastering likes to clip), more pure signal to reach the distribution mechanism.   So, with the DHNRDS you get more detail (less MD), which might produce more IMD on poor speakers, but also DHNRDS produces fewer errant peaks, thereby allowing a louder CLEAN signal (producing more IMD on cheap equipment) to result from normalization.   Maybe it IS better to listen to a poorer quality signal on a junk system?

* Fewer HF peaks due to use of linear phase filters -- no random peaks because of phase problems.  The LF filter is a normal IIR filter, but must be so because of a 100Hz freq response bump in DolbyA behavior.

 

Some people LIKE the sound of AM radio, apparently Frank is one of those people?

 

John

 

[John Dyson]

3 hours ago, fas42 said:

So you've got a good handle on what Michael Tretow was after, then?

It doens't have anything to do with the intentions of the ABBA engineer, but the general application of FOG everywhere (not just ABBA.)  The ABBA examples are easy because they come with a vocal chorus on many of their recordings -- easy to demo, and I happened to be cleaning up all of the original ABBA albums.   BTW -- I'll be you that Tretow wasn't necessarily listening to mix tape playback when mixing the audio -- he might have been, but it would have been more of a double-check.   The multi-track DolbyA per-track material is not nearly as damaged as a complex mix.   Even two raw vocals together won't be as badly damaged by DolbyA encode/decode as when added to the rest of the mix.

 

ABBA sounds 'great' when properly decoded (well, better than what ABBA sounds on their CDs and vinyl.)

 

BTW, the fog problem happens on more formal/'high brow' choral recordings just as much as ABBA.  The 'fog' also happens on orchestral material, vocals, almost any time that there is a mix of multiple sources (most of that kind of stuff I cannot distribute in ANY form -- even snippets.)   A single vocal -- not so bad.  Two vocals mixed together on a single track -- some damage (fog).  Lots of stuff -- esp with vocals -- fog city.

 

Any kind of live recording would not have considered DolbyA fog at all, and it is unlikely, but possible that DolbyA fog was considered in other, complex mix-down situations.

 

John

[John Dyson]

It is pretty clear that some people still misunderstand the purpose of my project (even though there is great benefit using the DHNRDS in production) -- the purpose is for ACCURATE historical playback.  It isn't intended to be optimized for playback on lower quality equipment.  The cool thing about the output of the DHNRDS -- one can add one's own choice of distortion after getting a clean signal to begin with.

Maybe some of ABBA was optimized for AM radio (The Visitors album does appear to be of higher quality though), but also the most accurate possible representation of their (or anyones) recordings are my goal.  (The output of the DHNRDS is able to clearly discern the gradiations in recording quality.)   For ABBA that is really poor audio quality - listen to the Arrival album.  You can hear the progression in quality over time -- up to the The Visitors album.   SuperTrouper is an interesting case -- I am still confounded by the first cut (SuperTrouper) on that album.  I cannot imagine what anyone was thinking about when mixing that mess (yes, the DHNRDS can even decode SuperTrouper very cleanly.)

 

Most interesting is the general clarity and performance of the DHNRDS on other material -- ABBA is my basket-case test vehicle.  My nerves grate when listening to ABBA right now, but it is a perfect test case for many forms of DolbyA distortion.

 

I am NOT interested in what happens when someone prefers inf:1 compression, horrible amounts of bass boost (or thin bass), or mono vs. 5.1 or whatever like that.  The goal is for accurate playback of original material -- the ultimate in Hi Res type quality, not the same old junk that people are sometimes stuck with.

 

192/24 without being decoded (or decoded poorly) is absurd, but there are some individuals who don't think that to be true. So be it -- if not interested in accuracy, and with speakers limited to 6kHz, why not be satisfied by 20.05kHz sample rate or mp3 at 96k?

 

John

[fas42]

15 hours ago, sandyk said:

 

We could safely bet that what he heard through his monitors when reviewing the session didn't sound remotely like what you hear through restricted frequency range laptop speakers.

 

 

 

So when other things fail, we fall back to the notorious, absolutely necessary, ruler flat FR ... hmmm? Quick question, will perfect FR, riddled with distortion, sound better than a craggy response curve, with excellent tonality qualities - or vice versa?

 

My preference, as will be obvious, is the latter - in fact, that's typical of very expensive headphones, .

 

Everyone wishes to miss the point that a simple playback setup should project the essence of what makes a recording special - and if that essence is poorly projected, then worrying about peripheral aspects is merely hunting for excuses ...

[fas42]

Note, the "fog" is the result of playback that is lacking - by simplifying what the playback chain has to handle then the subjective result is a lot more pleasant - give a car with lousy suspension a road with the bumps smoothed out, and your journey is a lot more comfortable.

 

It's recordings with 'intense', rich levels of mixing that become the most pleasurable to listen to when a rig is fully sorted - cheap brandy doesn't cut it any more, once you've experienced a well crafted, aged cognac.

 

I have an original mastering ABBA CD which is a fabulous journey of sound, gives me tremendous pleasure every time I listen to it - I have no desire to kill the glory of that experience, in the name of some audiophile rabbit hole ...

[John Dyson]

39 minutes ago, fas42 said:

Note, the "fog" is the result of playback that is lacking - by simplifying what the playback chain has to handle then the subjective result is a lot more pleasant - give a car with lousy suspension a road with the bumps smoothed out, and your journey is a lot more comfortable.

 

It's recordings with 'intense', rich levels of mixing that become the most pleasurable to listen to when a rig is fully sorted - cheap brandy doesn't cut it any more, once you've experienced a well crafted, aged cognac.

 

I have an original mastering ABBA CD which is a fabulous journey of sound, gives me tremendous pleasure every time I listen to it - I have no desire to kill the glory of that experience, in the name of some audiophile rabbit hole ...

I have by far MOST of the ABBA releases (including some ripped original vinyl) -- most are slightly mis mastered.  If you like them -- it is okay, it is up to you to enjoy.  (Actually, *every* one that I have checked has defects.)

 

It is good to enjoy -- because there is no perfection, including audiophile editions.  (Refer to the DolbyA leaks there also.)

 

I quit listening for enjoyment a lot time ago -- I am working on providing a BETTER experience, and making the original version of the music (as going into the encoding/tape deck in the actual recording session) available for future researchers.

 

John

[fas42]

5 minutes ago, John Dyson said:

 

I quit listening for enjoyment a lot time ago -- I am working on providing a BETTER experience, and making the original version of the music (as going into the encoding/tape deck in the actual recording session) available for future researchers.

 

John

 

John, I appreciate you are putting a lot of effort into what you're doing, and hence will listen in a "different way". Where I'm coming from is doing what's necessary for the playback chain to get out of the way completely - which I have found is necessary for listening "my way" ... I want to be completely unaware of the playback doing anything wrong, because hearing that occurring is too disturbing.

 

We're both about allowing a better experience - but doing it using different methods ...

[sandyk]

1 hour ago, fas42 said:

So when other things fail, we fall back to the notorious, absolutely necessary, ruler flat FR

 

You at least need to get the main VF range of 300 HZ to 3kHZ as flat as possible . This is the fundamental frequency  range for Telecommunications. Many Laptop speakers can't even do that well !

[John Dyson]

11 minutes ago, fas42 said:

 

John, I appreciate you are putting a lot of effort into what you're doing, and hence will listen in a "different way". Where I'm coming from is doing what's necessary for the playback chain to get out of the way completely - which I have found is necessary for listening "my way" ... I want to be completely unaware of the playback doing anything wrong, because hearing that occurring is too disturbing.

 

We're both about allowing a better experience - but doing it using different methods ...

 

I think that we have two totally different goals -- my goal is to improve OTHERs experience.   My own experience had been frustrated decades ago when the CDs sounded 'wrong'.  I got disgusted -- moved on totally focused with my engineering career, writing operating systems for a hobby, etc.  (My engineering career was crazy -- I mean, the lead systems engineer for first AT&T project for satellite TV, early HDTV research for consumer products, riding around on trains/trucks for vehicle location before GPS.)  The hobby was somewhat related to AT&T Bell Labs (where I worked) to also work on/develop the FreeBSD OS kernel.  I have had LOTS of fun -- and lets not even get into my 'Forrest Gump' emuation history - with my crazy 1 degree of separation.  I never got the major accomplishment of people in my midst (or nearby.)

 

Eventually, I had the time to research/discover/fix the old 'CD' problem -- and it turned into a roller coaster, then a nice landing for a  solution to the terrible old (and continuing) severe problem with the quality of digital audio as distributed to consumers.  See -- I knew that there was a problem with the sound of CDs back in the 80s -- but I kept hearing about the harsh/terrible stereo image digital sound.  I KNEW that the problem was NOT digital per-se, but was very suprised to find the real problem -- poor 'preparation' for digital distribution (not calling it 'mastering'), and lack of DolbyA decoding back in the day.

 

Too bad, I don't listen recreationally -- and my computer is busy doing test decodes all night when I am asleep.  

 

So -- some people might think that this problem with 'digital audio' is new -- nope, it has been continuing ---  and like the 'frog' in the boiling water, the sound has gotten worse and worse.  The initial 'start of the boil' was the DolbyA leaks back in the 80s'.  Now, we have almost 0dB dynamic range!!!

 

It would have been nice if there was a true scientific review to find the old 'harsh digital sound' in the 1980s, maybe with more open minds, we might not have quite the loudness wars today?  (Maybe -- maybe not.)  The distributors figured out that the consumer will purchase cr*p.

 

 

John

[fas42]

1 hour ago, John Dyson said:

 

I think that we have two totally different goals -- my goal is to improve OTHERs experience.   My own experience had been frustrated decades ago when the CDs sounded 'wrong'.  I got disgusted -- moved on totally focused with my engineering career, writing operating systems for a hobby, etc.  (My engineering career was crazy -- I mean, the lead systems engineer for first AT&T project for satellite TV, early HDTV research for consumer products, riding around on trains/trucks for vehicle location before GPS.)  The hobby was somewhat related to AT&T Bell Labs (where I worked) to also work on/develop the FreeBSD OS kernel.  I have had LOTS of fun -- and lets not even get into my 'Forrest Gump' emuation history - with my crazy 1 degree of separation.  I never got the major accomplishment of people in my midst (or nearby.)

 

 

My own journey was very different, of course, in the audio world ... was excited by the introduction of CDs, bought pretty well the best of the best for the time, in the electronics area; created a extremely simple system - immediately started tweaking. Premium digital sound, from CDs , popped out, as it always will if you get the integrity of the rig good enough - and I was set. Yes, everything else out there was making a mess of trying to reproduce CDs - I was just shaking my head every time I heard other rigs .

 

People couldn't get away with the sloppiness that was OK in the vinyl world - if you want digital playback to 'work', you must be fussy - and it's taken decades for people to slowly get the message - still not fully there yet.

 

Other people can get premium listening from digital, from recordings of the "bad ol' days" - but it's not trivial to do ... you still can't roll up to a store, and buy a bunch of cartons of stuff which will automatically make it happen ... this could still take decades to sort out - we'll see how it goes ...

[John Dyson]

1 minute ago, fas42 said:

 

My own journey was very different, of course, in the audio world ... was excited by the introduction of CDs, bought pretty well the best of the best for the time, in the electronics area; created a extremely simple system - immediately started tweaking. Premium digital sound, from CDs , popped out, as it always will if you get the integrity of the rig good enough - and I was set. Yes, everything else out was making a mess of trying to reproduce CDs - I was just shaking my head every time I heard other rigs .

 

People couldn't get away with the sloppiness that was OK in the vinyl world - if you want digital playback to 'work', you must be fussy - and it's taken decades for people to slowly get the message - still not fully there yet.

 

Other people can get premium listening from digital, from recordings of the "bad ol days" - but it's not trivial to do ... you still can't roll up to a store, and buy a bunch of cartons of stuff which will automatically make it happen ... this could still take decades to sort out - we'll see how it goes ...

I think that you misunderstand my point -- digital can be much better, but is voluntarily bad by poor 'preparation' for distribution.  Vinyl couldn't help but be not-so-good, but sometimes better than digital.  That SHOULD never be true.

We had a chance of getting 'really good' quality in our homes with CDs (or better), but instead we got a substitution for the poor vinyl quality -- that is ANOTHER kind of nonsense -- undecoded DolbyA and other such problems.  There was no need for that partial beginning of the 'loudness wars'.

 

An example in hand -- the Sheffield Labs disk with 'I got the music in me'...  Just so happens a current-forum correspondent hit on this -- my final irritation with CDs -- the CD was MUCH worse than the original direct to disk..  I never knew why -- but it was  MUCH worse.  In fact, it was worse than a lot of other 1980s CDs that were just bad.   My current-correspondent-friend from this forum sent me a copy of the 'I have a music in me', a raw version of the cut directly from the CD.   10 seconds with the knowledge that I have now --  IMMEDIATELY detected the pure undecoded DolbyA.  This is on exactly the CD that made me so disgusted to walk away back in the late 1980s (if Sheffield labs is bad, then it will always be bad) -- the darned CD is a pure -- UNEQed -- DolbyA copy!!!   If I get permission from my friend, I can demo it for you -- it makes me totally sick...*

 

* what makes me ever more sad nowadays, is even the audiophile 'ear' is distorted by the un-mastered material that has been prominent over these years.  This was probably the ongoing excuse for being a vinyl lover even today -- the digital downloads and CDs are really sub-par.

 

Sure, an average system with a CD will sound better than normal vinyl (back in the 1980's), but  there is ZERO ZERO ZERO excuse for the travesty of billions of CDs being produced with improper preparation ('mastering'.)   Much of that improper preparation is most likely due to the inconvenience of doing a DolbyA decode.  (My decoder being generally superior does remove that inconvenience in the digital realm -- but now, the previously intolerable, bad DolbyA sound is now acceptable to the audiphile ear.)  Even more sadly, people spend many $10ks on hardware that can never fix the terrible problem of mismastering.

 

John

 

[fas42]

1 hour ago, John Dyson said:

I think that you misunderstand my point -- digital can be much better, but is voluntarily bad by poor 'preparation' for distribution.  Vinyl couldn't help but be not-so-good, but sometimes better than digital.  That SHOULD never be true.

 

And you misunderstand mine, . Which is, that's there's nothing particularly wrong with what's mastered on the CD, but plenty wrong with the playback chain used for reproducing such - much of the time. Audiophiles have a magical  belief that their rigs are so good that they're telling them what's wrong with the recording - actually, it's the other way around. Which is mighty good news - anyone who gets a system working well enough to retrieve the musical event properly, gets to enjoy all this marvellous sound making - the archives of music are sitting there, waiting patiently to be finally recognised as the treasures they are ...

[fas42]

19 hours ago, sandyk said:

 

We could safely bet that what he heard through his monitors when reviewing the session didn't sound remotely like what you hear through restricted frequency range laptop speakers.

 

 

Alex, when a recording has been made to sound impressive, like this one I have never heard before, pointed to in the RMAF thread,

 

 

, it's trivially easy to hear, on the laptop, how a decent rig should impress playing this, with all the playing with spatial elements, and good capture of transients. It's when the mix is far murkier, more complex, that everything gets harder - but that's what a playback should do, bring out what matters, every time.

[lucretius]

3 hours ago, John Dyson said:

The hobby was somewhat related to AT&T Bell Labs (where I worked) to also work on/develop the FreeBSD OS kernel.  I have had LOTS of fun -- and lets not even get into my 'Forrest Gump' emuation history - with my crazy 1 degree of separation.  I never got the major accomplishment of people in my midst (or nearby.)

 

Did you know Ken Thompson, Dennis Ritchie and/or Brian Kernighan?

[sandyk]

Frank

 You are taking this WAY off topic. 

 Listening to John's files via a laptop's speakers does not give John the kind of feedback (good or bad) that he requires for his project.

[fas42]

Just started looking at some of the samples John posted, using DeltaWave; this is the  [Olivia Newton-John] Have You Never Been Mellow track,

 

 

Blue is the RAWundecoded, Red is the V0.9.7K1 version - the gains are perfectly matched, below 2K, and you're looking here at the above 2kHz content - the spectrum shows the decoding starting to cut treble at 2k, and it reaches a 14dB cut by 20kHz - which is reflected in the above. Also, the transients are severely smoothed out, note the failure of the K1 to follow the RAW at 6.18 secs - 0.005 secs later the K1 signal has finally reached the peaks, approximately, of the RAW.

 

If people believe this is showing them more of what's in the recording, that's fine - but I don't accept it.

[sandyk]

From Wiki :

Quote

Dolby A

Dolby A was the company's first noise reduction system, presented in 1965.^[1] It was intended for use in professional recording studios, where it became commonplace, gaining widespread acceptance at the same time that multitrack recording became standard. The input signal is split into frequency bands by four filters with 12 dB per octave slopes, with cutoff frequencies (3 dB down points) as follows: high–pass at 80 Hz; band–pass from 80 Hz to 3 kHz; a low–pass from 3 kHz; and another low–pass at 9 kHz. (The stacking of contributions from the two low-pass bands allows greater noise reduction in the upper frequencies.) The compander circuit has a threshold of -40 dB, with a ratio of 2:1 for a compression/expansion of 10 dB. This provides about 10 dB of noise reduction increasing to a possible 15 dB at 15 kHz, according to articles written by Ray Dolby in JAES (October 1967) and Audio (June/July 1968).

As with the "B" system, correct matching of the compression and expansion processes is important. The calibration of the expansion (decoding) unit for magnetic tape uses a flux level of 185 nWb/m, which is the level used on industry calibration tapes such as those from Ampex; this is set to 0 VU on the tape recorder playback and to Dolby Level on the noise reduction unit. In the record (compression or encoding) mode a characteristic tone (Dolby Tone) generated inside the noise reduction unit is set to 0 VU on the tape recorder and to 185 nWb/m on the tape.

Dolby A also saw some use as the method of noise reduction in optical sound for motion pictures.

 

[John Dyson]

2 hours ago, lucretius said:

 

Did you know Ken Thompson, Dennis Ritchie and/or Brian Kernighan?

Those guys were pretty much legacy when I was working on OS stuff -- I did deal with Linus a lot (mostly in a negative way.)   One of my current (active) friends/co-workers did write the original 'AS' command and the never-used-today 'xref/cref' command (I'm not 100% sure).  But the 'as' command thing doesn't count :-).

 

At Bell Labs, I mostly wrote small OS type stuff, ran projects (ran a group for a short time), wrote/optimized a lot of C/ASM code, worked on forward looking projects that no-one knew how to do (I am an EE/software engineer -- back then, I still did digital EE also, now I just do analog -- totally interdisciplinary in the EE/computer, which was needed on complex & impossible-to-do projects.  Even then, there werne't many totally competent analog EE & computer people at the same time.)

 

I knew a few internet pioneers at the start -- one started a service that is still be used (sort of.)   My guess off the top, would be about 10 items.   Perhaps the FIRST item:   first boss knew/worked for T A Edison and Edison knew him (there is a skip cheat there -- Edison IS a special case.)   I won't ask for credit about TAE knowing JPM though :-).   At the same place (doesnt count in the list), Kurward Derby (or Durward Kirby's mic was sitting in the next room (is very minor issue), when I was 17yrs old -- only US oldsters would know that reference -- partially from Rocky & Bullwinkle -- Durward Kirby old radio guy & side-kick like McMahon 20yrs earlier, but that place was a 'museum' on an obscure side-street in Indy, was still broadcasting in 1972.)   I cannot remember all of my near-misses of knowing greatness or knowing it very indirectly as an observer --  off the top but the Edison thing was the first -- but it seems like I would have a close 0th or 1st degree encounter like that every 1-2 yrs.

 

A few months ago, I came up with over 10 of those kinds of things for a friend (some  more substantial than the indirect Edison thing.)  Several of them were computer related, one group of three invented a MAJOR important piece of military technology still very relevent (possible that a classification mistake made me a LEGAL leak of one of the secrets.)

 

So, I could only come up with one significant item above right now, but I know that there are lots more -- I cannot remember them all (they weren't important to me at the time, then I get reminded by those who were around when I was really active.  Alas, people are fading away -- that first boss guy left us back in about middle 1970s  (he was old, even older than I am now.)  My co-workers who invented the cruise missile guidance (patents) are probably all gone now -- lots of things/people are drifting away.  Those guys probably knew some people who developed the Norden bomb sight.

 

Bell labs gave me a few connections/or saw nearby greatness, a few contacts in my FreeBSD project, a few in my younger years (like Edison).  Geesh, it doesn't count, but a current friend/correspondent did the audio for a major US TV network years ago.  He is now a pretty good friend, but the DA project has developed interest from people like Grammy winners.  THAT does NOT count yet.

 

*  My memory of time-sequential things is SO bad that my 85yr old dad many years ago had to remind me about the Edison connection -- I simply forgot stuff like that, even though I knew it happened.  It usually takes me a few days to remember stuff like that.  The connections were NEVER in my reality when I was younger.  I'd meet/work with people, not knowing what they had done in the past.

 

*The one time that I was recognized outside of my immediate context weirded me out that it was probably the start of me pulling back into total obscurity.  I was at a Speedway station, purchasing gas in Indianapolis -- TOTALLY AWAY from my context of working & visibility WRT Si Valley doing the FreeBSD kernel...  On using my credit card, I was asked if I was *that* John Dyson -- I asked *what* John Dyson, he said the one who did the FreeBSD kernel.  A few years later, after a few more weird things, I pulled back and hid.  I squandered a lot because of my aversion to certain kinds of public things.

 

I HAVE NEVER DONE ANYTHING SUBSTANTIAL, but I had always been a 'go-to' person to solve problems (esp at Bell Labs consumer products.)  I was always given the super-forward-looking projects, and even though we got things done, it never amounted to much.  I should have contributed more REAL things.  There were lots of 'almosts' (I mean, really almost), like spending $100Ms getting a satellite launched.   Lots of potential, not ending up with much.  (I think most of the problem was my lack of communication skills, and always getting the SUPER impossible projects  -- but now, because of a physical hit, I cannot even speak more than a few words without losing my voice.)

 

John

 

[John Dyson]

2 hours ago, fas42 said:

Just started looking at some of the samples John posted, using DeltaWave; this is the  [Olivia Newton-John] Have You Never Been Mellow track,

 

 

Blue is the RAWundecoded, Red is the V0.9.7K1 version - the gains are perfectly matched, below 2K, and you're looking here at the above 2kHz content - the spectrum shows the decoding starting to cut treble at 2k, and it reaches a 14dB cut by 20kHz - which is reflected in the above. Also, the transients are severely smoothed out, note the failure of the K1 to follow the RAW at 6.18 secs - 0.005 secs later the K1 signal has finally reached the peaks, approximately, of the RAW.

 

If people believe this is showing them more of what's in the recording, that's fine - but I don't accept it.

 

Actually, YOU misunderstand what DolbyA does then.  Its intent is to 'bunch up' the signal above the noise in a tape recorder.  Then, it 'expands'  the signal back to the original dynamics.  The difference between DolbyA HW and DHNRDS DA is that the DHNRDS avoids creating some side effect distortion mechanisms.

 

Listening to DolbyA encoded material (you ARE doing so) without decoding is a lot like listening to MQA without fully unfolding.

 

DolbyA is NOT intended to be a sound effect -- as it does it poorly, but you seem to enjoy the lousy, unintended sound of undecoded material?  Does that lousy sound call into question the taste of those who like undecoded DolbyA?

 

The unintended sound of undecoded DolbyA is tantamount to distortion.  Normally, I try to avoid distortion, not embrace it.

 

All the DHNRDS does is to recover the original sound as recorded into the DolbyA/tape recorder complex.  It does nothing more/nothing less.  It is NOT a sound effect.  The DHNRDS does the signal recovery either approx equivalent to the DolbyA HW (in one mode), or in one of the super modes, ferrets out almost every little bit of modulation distortion that a normal DolbyA would cause.

 

Currently, listening to much of the available digital material, YOU ARE HEARING DISTORTED SOUND -- per the DolbyA encoding process.  In some ways, the distorted sound that you likely listen to is not a lot different than MQA, but better intentioned.

 

The DolbyA/DHNRDS DA decoding process removes most of the DolbyA encoding distortion, where the DHNRDS does it better.

 

 

 

John

[fas42]

Can't reply properly at the moment - tech issues and jobs to do... back later... 

[sandyk]

16 hours ago, John Dyson said:

Listening to DolbyA encoded material (you ARE doing so) without decoding is a lot like listening to MQA without fully unfolding.

 

 Or like playing a vinyl record with a high output moving coil cartridge into a low noise op amp with a gain of around 100

without an RIAA compensation network ! 

[fas42]

21 hours ago, John Dyson said:

 

Actually, YOU misunderstand what DolbyA does then.  Its intent is to 'bunch up' the signal above the noise in a tape recorder.  Then, it 'expands'  the signal back to the original dynamics.  The difference between DolbyA HW and DHNRDS DA is that the DHNRDS avoids creating some side effect distortion mechanisms.

 

I had a, decent, cassette tape deck over 40 years ago - I know what Dolby is doing, .

 

Quote

Listening to DolbyA encoded material (you ARE doing so) without decoding is a lot like listening to MQA without fully unfolding.

 

The Big Point is whether this "Dolby A encoded" material is a Big Mistake by the studios - or precisely what was intended when they released it. So, have we had generations of completely incompetent people in the business, and no-one's picked it, ?

 

Quote

 

DolbyA is NOT intended to be a sound effect -- as it does it poorly, but you seem to enjoy the lousy, unintended sound of undecoded material?  Does that lousy sound call into question the taste of those who like undecoded DolbyA?

 

Lousy subjective sound  is a function of flaws in the playback chain - and digital can sound pretty 'orrible when the rig is not working properly. Dolby A "infested" sound will come across as intense and driving, but it requires the reproduction to be done right.

 

Quote

The unintended sound of undecoded DolbyA is tantamount to distortion.  Normally, I try to avoid distortion, not embrace it.

 

I don't hear distortion in CDs played on a system that's working correctly. But I've heard oodles of poorly sorted, ambitious setups make a complete mess of CDs I know well - do you understand what the key issue in all this is?

 

Quote

 

All the DHNRDS does is to recover the original sound as recorded into the DolbyA/tape recorder complex.  It does nothing more/nothing less.  It is NOT a sound effect.  The DHNRDS does the signal recovery either approx equivalent to the DolbyA HW (in one mode), or in one of the super modes, ferrets out almost every little bit of modulation distortion that a normal DolbyA would cause.

 

Currently, listening to much of the available digital material, YOU ARE HEARING DISTORTED SOUND -- per the DolbyA encoding process.  In some ways, the distorted sound that you likely listen to is not a lot different than MQA, but better intentioned.

 

The DolbyA/DHNRDS DA decoding process removes most of the DolbyA encoding distortion, where the DHNRDS does it better.

 

 

 

John

 

You say the recordings are distorted ... I say the playback chain is what's distorting - if you have never heard how spectacular those "poor" recordings can sound when reproduced well, then that's a pity - but don't make the mistake of putting the proverbial cart before the horse, .

[John Dyson]

7 hours ago, fas42 said:

 

I had a, decent, cassette tape deck over 40 years ago - I know what Dolby is doing, .

 

 

The Big Point is whether this "Dolby A encoded" material is a Big Mistake by the studios - or precisely what was intended when they released it. So, have we had generations of completely incompetent people in the business, and no-one's picked it, ?

 

 

Lousy subjective sound  is a function of flaws in the playback chain - and digital can sound pretty 'orrible when the rig is not working properly. Dolby A "infested" sound will come across as intense and driving, but it requires the reproduction to be done right.

 

 

I don't hear distortion in CDs played on a system that's working correctly. But I've heard oodles of poorly sorted, ambitious setups make a complete mess of CDs I know well - do you understand what the key issue in all this is?

 

 

You say the recordings are distorted ... I say the playback chain is what's distorting - if you have never heard how spectacular those "poor" recordings can sound when reproduced well, then that's a pity - but don't make the mistake of putting the proverbial cart before the horse, .

The  DolbyA deocoding (unfolding in MQA parlance) is what is missing...  The unintended dynamic range compression reaching the consumer is a fault, and tantamount to a form of distortion.

 

The fault is not with the studios -- I am sure that Hoffman didn't intend that the Nat King Cole stuff would reach the consumer with DolbyA encoding intact (or whomever did it at AP), it was someone missed the step of decoding. 

This lack of decoding (unfolding in MQA paralance) is a fact, and is attested to by someone actual doing album compilations in the Gearslutz forum (and I have private commentary elsewhere from pro recording engineers.)

 

The DolbyA decoding of some of the digitally finalized material is a real pain in the b*tt because it requires a realtime D/A->DolbyA->A/D transfer.  Not so with the DHNRDS -- it is all digital, and can run faster in realtime when doing DolbyA HW quality decodes.  The super quality decodes that remove the DolbyA fog are only realtime -- but that could be remedied.

 

If you cannot hear the difference, or prefer the dynamic range compressed sound -- that is for you to enjoy, but it is a technical flaw.

 

Below, I am showing (again) an undecoded and DHNRDS version of The Carpenters singles album, cut 12 as sold by HDtracks.  The better HF balance and hiss reduction are simple results of the demoed DolbyA decoding.  If being around for 40yrs or more, sometimes we loose HF hearing, and so might not hear much difference.  Even with my 63yr old hearing, the improvement is obvious (still not perfect, I didn't tune the decoding as carefully as normal -- this was a quick decode-- should be within 0.1dB or so.)  There is all kinds of evidence that this material is DolbyA encoded (not 'unfolded' as in MQA parlance.)   This kind of things is so very common, even in 'audiophile' recordings.

 

* With the 'Superstar' example, the undecoded is 'brighter', but the cymbals/percussion all the same level on the undecoded (wrong).  This is due to dynamic range compression.  The decoded version has both softer and louder cymbals, which is correct.

 

Not decoded - gritty, grainy, hissy -- dynamic HF boost WRT input the DolbyA/tape recorder complex

DHNRDS - less gritty, less grainy, less hissy -- flat WRT input into the DolbyA/tape recorder complex

(DHNRDS version had to be re-uploaded -- I forgot the correct calibration -- corrected.)

(Usually, not always, a quick check with sox will show a bit wider dynamic range upon decoding, but sox only measures the high level dynamic range, not the hiss reduction and regularization of the middle/lower dynamics)

 

Full through and through 96k/24 flac available on request for comparison. * all above 20kHz HF signals and original encoding splats still included :-).

 

John

 

12-Hurting Each Other [1991 Remix]-notdecoded.mp3

 

03-Superstar-notdecoded.mp3

03-Superstar-DHNRDS.mp3

12-Hurting Each Other [1991 Remix]-DHNRDS.mp3