sandyk (RIP Alex, 1939 - 2021)
Global Moderator
Posts: 226
About Me: Retired ex Principal Telecommunications Technical Officer with 43 years at Telstra (Australia)
I am also a Moderator in Hi Fi Critic Forum
Electronics hobbyist for >65 years with DIY projects including Loudspeakers, Stereo FM tuner, S/W Regen Receiver, Superhet AM ,
Synchrodyne PLL AM tuner (Phase Lock Loop),Stereo Tape Deck, Amplifiers including I.C. types, Class A, Class AB 100W/Ch. (ETI5000) 240W/Ch. Mosfet (AEM6000) ,several DACs , numerous PSUs including VERY low noise (<4uV) types etc.for myself and friends
Audio Industry Affiliation: NIL
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Post by sandyk (RIP Alex, 1939 - 2021) on Sept 18, 2019 9:32:06 GMT 10
Currently, highly experienced E.E. John Dyson is working on a project to preserve for future generations, quite a few famous CD releases from earlier years where they didn't correctly implement (if at all) the decoding from the Dolby A noise reduction system used at the time. This made many earlier releases sound shrill and even irritating. John is using mainly ABBA for this as it has by far the most problems . Even many earlier releases from other albums including The Cars, Carly Simon, The Carpenters, Nat King Cole and Olivia Newton John suffered from these problems too. John's Software program " DHNRDS" is far more accurate than the original Dolby -A decoders, and is even capable of reducing or eliminating artifacts caused by the original Dolby-A encoding
If anybody is interested in hearing what John is achieving for preservation purposes, please send me a PM and I will send you FYI Only, an example with a complete track. John will appreciate any feedback that we are able to provide.
In fact, the improvements are so good with some of the more difficult Abba material from Polar Records , that it is possible that later down the track the Record Companies may even consider releasing the corrected versions.
Regards Alex
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Post by ROWUK on Sept 18, 2019 14:43:27 GMT 10
This interests me very much! I also have some dbx type 1 and 2 encoded stuff with no proper decoder. I would think that this could be handled in the digital domain by dsp, I have not yet found the right tool.
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sandyk (RIP Alex, 1939 - 2021)
Global Moderator
Posts: 226
About Me: Retired ex Principal Telecommunications Technical Officer with 43 years at Telstra (Australia)
I am also a Moderator in Hi Fi Critic Forum
Electronics hobbyist for >65 years with DIY projects including Loudspeakers, Stereo FM tuner, S/W Regen Receiver, Superhet AM ,
Synchrodyne PLL AM tuner (Phase Lock Loop),Stereo Tape Deck, Amplifiers including I.C. types, Class A, Class AB 100W/Ch. (ETI5000) 240W/Ch. Mosfet (AEM6000) ,several DACs , numerous PSUs including VERY low noise (<4uV) types etc.for myself and friends
Audio Industry Affiliation: NIL
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Post by sandyk (RIP Alex, 1939 - 2021) on Sept 18, 2019 16:02:42 GMT 10
This interests me very much! I also have some dbx type 1 and 2 encoded stuff with no proper decoder. I would think that this could be handled in the digital domain by dsp, I have not yet found the right tool. Hi Robin I will include a copy from the original Swedish 1st release POLCD -242 album to give some idea of the differences, as well as 2 recent versions from John which will not be the final version of this track, but close to it. The POLCD -242 version isn't probably quite as good as the one John has access to, but sounds way better then the compilation album with different mastering that an A.S. forum member has. The differences between the other 2 versions from John are quite small. See if you are able to pick them.
Regards Alex
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sandyk (RIP Alex, 1939 - 2021)
Global Moderator
Posts: 226
About Me: Retired ex Principal Telecommunications Technical Officer with 43 years at Telstra (Australia)
I am also a Moderator in Hi Fi Critic Forum
Electronics hobbyist for >65 years with DIY projects including Loudspeakers, Stereo FM tuner, S/W Regen Receiver, Superhet AM ,
Synchrodyne PLL AM tuner (Phase Lock Loop),Stereo Tape Deck, Amplifiers including I.C. types, Class A, Class AB 100W/Ch. (ETI5000) 240W/Ch. Mosfet (AEM6000) ,several DACs , numerous PSUs including VERY low noise (<4uV) types etc.for myself and friends
Audio Industry Affiliation: NIL
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Post by sandyk (RIP Alex, 1939 - 2021) on Sept 28, 2019 14:34:53 GMT 10
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sandyk (RIP Alex, 1939 - 2021)
Global Moderator
Posts: 226
About Me: Retired ex Principal Telecommunications Technical Officer with 43 years at Telstra (Australia)
I am also a Moderator in Hi Fi Critic Forum
Electronics hobbyist for >65 years with DIY projects including Loudspeakers, Stereo FM tuner, S/W Regen Receiver, Superhet AM ,
Synchrodyne PLL AM tuner (Phase Lock Loop),Stereo Tape Deck, Amplifiers including I.C. types, Class A, Class AB 100W/Ch. (ETI5000) 240W/Ch. Mosfet (AEM6000) ,several DACs , numerous PSUs including VERY low noise (<4uV) types etc.for myself and friends
Audio Industry Affiliation: NIL
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Post by sandyk (RIP Alex, 1939 - 2021) on Oct 3, 2019 13:37:48 GMT 10
John Dyson has given me permission to share, for personal use only, 21 corrected tracks from Abba, The Carpenters, and Olivia Newton John. They have all been passed through the Decoder and saved as 24 /88.2 /flac files. If you would like to hear or save them for personal use, please send me a PM Regards Alex
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Post by ROWUK on Oct 3, 2019 15:00:38 GMT 10
Hi Alex, I have a weekend without a concert and would be VERY interested.
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sandyk (RIP Alex, 1939 - 2021)
Global Moderator
Posts: 226
About Me: Retired ex Principal Telecommunications Technical Officer with 43 years at Telstra (Australia)
I am also a Moderator in Hi Fi Critic Forum
Electronics hobbyist for >65 years with DIY projects including Loudspeakers, Stereo FM tuner, S/W Regen Receiver, Superhet AM ,
Synchrodyne PLL AM tuner (Phase Lock Loop),Stereo Tape Deck, Amplifiers including I.C. types, Class A, Class AB 100W/Ch. (ETI5000) 240W/Ch. Mosfet (AEM6000) ,several DACs , numerous PSUs including VERY low noise (<4uV) types etc.for myself and friends
Audio Industry Affiliation: NIL
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Post by sandyk (RIP Alex, 1939 - 2021) on Oct 3, 2019 18:29:22 GMT 10
John Dyson has given me permission to share, for personal use only, 21 corrected tracks from Abba, The Carpenters, and Olivia Newton John. They have all been passed through the Decoder and saved as 24 /88.2 /flac files. If you would like to hear or save them for personal use, please send me a PM Regards Alex
Hi Robin Bear in mind that although they may sound quite mediocre by today's standard, they are quite a bit improved over the originally released CDs, especially as regards Sibilance and distortion. Kind Regards Alex
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Post by cj66 on Oct 3, 2019 22:16:22 GMT 10
Hi Alex,
That's great and very generous of John to give his blessing.
I'd be particularly interested in The Carpenters material, very deserving of a magic wand IMHO. Mainly curiosity on the others.
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Post by ROWUK on Oct 4, 2019 4:32:49 GMT 10
John Dyson has given me permission to share, for personal use only, 21 corrected tracks from Abba, The Carpenters, and Olivia Newton John. They have all been passed through the Decoder and saved as 24 /88.2 /flac files. If you would like to hear or save them for personal use, please send me a PM Regards Alex
Hi Robin Bear in mind that although they may sound quite mediocre by today's standard, they are quite a bit improved over the originally released CDs, especially as regards Sibilance and distortion. Kind Regards Alex
Hi Alex, I have some Cds and LPs for comparison. I have no doubt that modern mastering can offer considerable advantages - if the engineer has ears and a reasonable budget. Generally pop music suffers from grossly exaggerated effects. A „natural“ soundstage was not the goal. Whether the multitrack masters are still available, is a deciding factor. I will give it all a listen.
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sandyk (RIP Alex, 1939 - 2021)
Global Moderator
Posts: 226
About Me: Retired ex Principal Telecommunications Technical Officer with 43 years at Telstra (Australia)
I am also a Moderator in Hi Fi Critic Forum
Electronics hobbyist for >65 years with DIY projects including Loudspeakers, Stereo FM tuner, S/W Regen Receiver, Superhet AM ,
Synchrodyne PLL AM tuner (Phase Lock Loop),Stereo Tape Deck, Amplifiers including I.C. types, Class A, Class AB 100W/Ch. (ETI5000) 240W/Ch. Mosfet (AEM6000) ,several DACs , numerous PSUs including VERY low noise (<4uV) types etc.for myself and friends
Audio Industry Affiliation: NIL
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Post by sandyk (RIP Alex, 1939 - 2021) on Oct 14, 2019 8:08:10 GMT 10
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Post by cj66 on Oct 14, 2019 13:06:43 GMT 10
I've just had a wee listen to one track in particular, mainly because I know it well and have a supposedly "good" copy of it. The Carpenters "I Won't Last Another Day Without You". Using pretty basic equipment I compared small snippets at a time after setting the volume levels as equallly as I could perceive. On first listen the Dysoned version seemed like a combination of more realistic tone, the piano especially but also a bit closed in. A couple of passes later it was obvious my existing copy was very "hot" in the higher frequencies and posessed an overly live sound, possibly artifacts of the studio enviroment laid bare by the extreme HF content? Once tuned in the new mix was far more pleasant, everything was still there but nothing magnified, Karens voice displayed a warmer, more intimate tone, the piano didn't peel your ears off and the drums had an easy, mellow flow, a very typical studio sound for a drum kit rather than the hard bish, bosh clang that went before. I think I'm so used to the original mixes, that this and several more tracks I've had a quick listen to, are almost culture shock. Abba was very enlightening, so they didn't mean it to sound like an old tin can! Now Mr. Dyson, how about some of those nasty sounding rock albums from the 70's and early 80's ...
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Post by Audiophile Neuroscience on Oct 14, 2019 15:18:39 GMT 10
Now Mr. Dyson, how about some of those nasty sounding rock albums from the 70's and early 80's ...
Yeah , when I want to get 'my rock on' I try to listen to some Stones. Alas it doesn't take long before the paint starts peeling and I wish for the "Dysonizer".
BTW 1995 Stripped is actually not too bad, a mixture of live and "acoustic studio recordings". My fav probably "Love in Vain" inclusive of the "Arthur Peggio" broken chord moment !
David ----------------------------------------------------------------------------------------------------------------------------- "All music is folk music. I ain't never heard no horse sing a song." - - Louis Armstrong
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Post by johndyson on Oct 14, 2019 22:03:55 GMT 10
<abbr>I got these messages about the decoded versions of ABBA and the Carpenters. I have better results coming -- some tonight, more tomorrow.</abbr> <abbr>The problem with some of the 'decoding' is to get the material as supplied on CD (or other means) into the form where DolbyA can decode it. Very often (in fact, most often), the material has been 'meddled with' to make the DolbyA encoded material sound acceptable. Of course, the leftover sound of the 'undecoded', but instead only EQed material is a compressed high end and sometimes even LF distortion!!! (The attack/release time of DolbyA encoding is insanely fast for 50Hz signals, let alone lower frequencies.)</abbr> It wasn't really planned that DolbyA encoded material NOT be decoded, so the lingering distortion and HF compression will persist on undecoded material.
Someone, sometime figured out that in this world of pop/rock, that people will tend to accept the missing DolbyA decoding, and accept it as yet another form of 'compressed sound'. I do have to moderate my comments by the very important fact that R Dolby was a genius and designed his DolbyA hardware with secrets that all but the most perceptive EE reading the schematics, will gloss over. This is probably one reason why an alternative use for DolbyA processors was to do HF enhancement for vocals/etc (if used for that purpose -- seem to work okay.) However, a simple redesign without these stealthly considerations in the compressor designs, they WILL get more distortion than what they would expect. This is probably one reason why people give up and just use a DolbyA for HF enhancement.
If you have heard the true raw output of a DolbyA, it would most likely be deemed unlistenable. Only after at least 3-6dB cut at 3kHz and maybe another 3dB cut at 6kHz or 9kHz does raw DolbyA become listenable. This is the errsatz mastered material that started appearing on CDs back in the 80's, even to today. Probably also a big reason for the unexpected (harsh, digital) sound of CDs in the early days, and often continuing on to today. One side benefit for the industry: vinyl is usually properly decoded, and allows for a layerd 'audiophile' product, yet still damaged enough that it cannot be used for commercial redistribution.
By distributing DolbyA with EQ (and in some cases raw DolbyA on 99 Red Balloons/Nena CD and Sheffeild Labs CD with Thelma Houston -- have RAW DolbyA!!!) -- these distributors are ALMOST selling their 'family jewels' to consumers -- it is just that we consumers didn't realize it!!!
The hard part about decoding the DolbyA material -- UNDOING the errsatz-mastering. That is, doing 'corrective EQ' to bring the material up to the level that it can be properly decoded by a DolbyA compatible decoder... (My decoder IS better than DolbyA HW -- only because DSP can do fancier things).. My challenge, evidenced that most of my decoding attempts are not perfect, is to second guess what EQ was done for the pre-distribution mastering. Then, I have to undo that EQ before running it through the decoder.
There is a double edged sword with my DolbyA compatible decoder (DHNRDS DA) -- that 'sword' is that the DHNRDS is very smart about working with out-of-standard material. So, when a true DolbyA might start producing more IMD or MD because of calibration errors or frequency response problems, instead the DHNRDS is REALLY GOOD at removing errant modulation products. So, for an initial tune-up for proper calibration/EQ, it is a bit more sensitive to use one of the DHNRDS modes that disables the anti-IMD/anti-MD mechanisms.
Tonight, I hope to have a new library of all of the original ABBA albums ready (I have been trying to fine-tune Arrival -- a real mess), and Carpenters/Olivia/etc are forthcoming. The law keeps me from freely distributing all of the results, but I will DEFINITELY supply subsets for demonstration.*
Sincerely and really trying to work for the listeners!!! (Actually trying to make groups like ABBA & Carpenters sound more like their original vinyl -- but better) My DolbyA copies of Olivia NJ already sound pretty good, but my newly decoded versions truly 'knock my socks off'. Alex hasn't even heard the latest version of ONJ yet -- I don't want to waste ANYONES time yet until I am totally happy with results. (Also fighting the variability of my hearing/perception/etc for quality control matters.) I respect Alex's time too much to blast him with iterative releases of many albums :-).
John
* Admittedly, the DHNRDS is always being improved. My recording restoration expert project partner has the attitude that I am guilding the lily. He is truly a WONDERFUL person, but doesn't seem to understand the sensitivities of a lot of people in the audiophile community. Some of the changes that I am making are super carefully considered and for at least the last 3 months, the DHNRDS produces 99.999% better audio quality than a real DolbyA for decoding -- period. The changes and centering of measurement apertures and very good IMD reduction with further MD reduction with very CPU intensive, highly proprietary algorithms, greatly reduces the DolbyA fog sound.
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sandyk (RIP Alex, 1939 - 2021)
Global Moderator
Posts: 226
About Me: Retired ex Principal Telecommunications Technical Officer with 43 years at Telstra (Australia)
I am also a Moderator in Hi Fi Critic Forum
Electronics hobbyist for >65 years with DIY projects including Loudspeakers, Stereo FM tuner, S/W Regen Receiver, Superhet AM ,
Synchrodyne PLL AM tuner (Phase Lock Loop),Stereo Tape Deck, Amplifiers including I.C. types, Class A, Class AB 100W/Ch. (ETI5000) 240W/Ch. Mosfet (AEM6000) ,several DACs , numerous PSUs including VERY low noise (<4uV) types etc.for myself and friends
Audio Industry Affiliation: NIL
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Post by sandyk (RIP Alex, 1939 - 2021) on Oct 15, 2019 11:56:38 GMT 10
Hi John Many thanks for your in-depth reply. It is much appreciated. It's great to know that future generations will be able to hear many of these famous recordings from the 20th Century the way they were intended to be heard, not as they were with many releases due to the lack of due diligence in the preparation of the final CD master. Luckily , we still have people like yourself and Barry who really care about the quality of the material that is provided to the public.
Kind Regards Alex
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Post by johndyson on Oct 31, 2019 13:54:01 GMT 10
Good news -- I have to announce this somewhere because it IS a major breakthrough in the DHNRDS DA decoder.
This is a long background story that no-one wants to hear, but the bottom line, I ended up looking again at the DHNRDS DA decoder for distortion issues. After chasing down some rabbit holes and revisiting the design goals, I had realized that my original goals were 'bug for bug', but better than DolbyA HW. I believe that goal was wrong. I changed the 'goal' temporarily -- I believe it is now a permanent change. NOW -- the goal is 'Better than DolbyA HW... period.'. I stripped out some of the emulation code that supports some of the DolbyA HW bugs. For example, one of the bugs is that the signal attacks have a limited slew rate because the effective drive voltage is limited when running in expander mode. I stripped out the 'drive voltage' limitation in the code (of course, an emulation), and lo-and-behold, the garble that happens on complex/mixed large signals that happens with DolbyA units and also the previous DHNRDS versions is now pretty much GONE.
The previous DHNRDS DA version was pretty good at getting rid of the DolbyA HW decoding fog at low levels, but that doesn't happen nearly as often as the louder mixed chorus and mixed instruments. With this modification, the DHNRDS DA can now track the signal more accurately than previously and more accurately than the DolbyAHW -- thereby reducing the high level garble.
My initial evaluation of the improvement produces results almost as important as the initial versions that were often better better than DolbyA HW. There is a very significant improvement in sound quality.
I will check into a few matters regarding forum message distribution/etc, but if it is small enough, I'll provide a repository for examples in the next few days.
If this was not a major improvement -- I would NOT have bothered posting this message. This upcoming change will make a much more significant improvement in decoding results over previous DHNRDS versiona AND DolbyA versions. I wouldn't be surprised that a lot of material will be heard much more similarly to the original input to the DolbyA/Tape recorder complex.
Some very difficult material, including ABBA (the recordings that I use for my ACID tests), are sounding very errie.... Stuff like 'SuperTrouper' actually sounds almost natural?!?! Bread is really, really, really nice sounding, and the Carpenters recordings are coming out better than I have EVER heard.
Examples will be forthcoming -- next few days. Anyone who has REALLY EVIL DolbyA material that they'd like to resurrect -- I can supply a decoder, or even do a decoding operation gratis (I am very good about keeping private/unpublished/NDA material private, and happily destroy temporary copies.) The DHNRDS can make DolbyA material sound less foggy, have better vocal chorus (less rough mixing), lots of other improvements.
John
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