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'FeralA' decoder -- free-to-use


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On 2/11/2021 at 6:35 PM, John Dyson said:

There are still some delays...   But I want to warn about expectations -- because the result will definitely sound different than the original consumer messed up garbage.

 

1)  The normally available consumer material has an artificially boosted lower midrange, which comes from both EQ and LF distortion.   The EQ is corrected by decoding, which then removes that tubby FA sound.   It takes a while to get used to the missing tubby sound.   Even expert audiophiles have gotten used to it.  I regularly listen to copies of actual masters -- never being touched by the distribution damage.

 

2) The decoder should be relat ively flat, but I have been fighting against a 3dB peak at 9kHz.   That artificially brightens vocals, and creates an edge.    The peak is relatively narrow, and that is why I didn't notice.   The current code has the peak removed.   I am still working on other aspects of the EQ -- the EQ needs to be spread amongst each decoding layer vs. the single input/output.   If the combination is correct (the previous version was correct except for the peak) so maintianed consistent frequency response vs. # of layers of decoding.

 

3)  A recent complaint about certain sounds disappearing is a valid comment, but respectfully invalid complaint.   Low level, esp high frequency sounds on FA recordings are artifically boosted, and the listener might have gotten used to the 'boosted' version.   Sometimes, the decoder will push the near-noise level signal into near oblivion.   That is how noise reduction works.

 

When the new decoder comes out, PLEASE don't be disappointed by the screwed up midrange from consumer recordings being missing.

 

The result is sometimes a 'thin' sound, sometimes sounding low too-strong vocal midrange when compared with lower midrange.  The fact is -- the lower midrange SHOULD be diminished.

 

There is a total refactoring of the EQ to get rid of the 9kHz boost.   This refactoring is producing very similar results -- missing 9kHz peak.

 

I'd expect a few more weeks delay.

 

HI John,

 

I have been following your work online over the last few days since I had reason to investigate DolbyA in depth, and I 100% agree with you on the leaking of DolbyA into the consumer world.

 

I have no direct examples myself but from my work and experience within the record industry I can 100% see how this can happen easily.

 

I have a rather unique view of the industry in that I was brought up within the world or recording and also manufacturing and sales. I have literally experienced everything from recording in pro studios to home recording and from Vinyl cutting and pressing, cassette manufacture and CD production (not directly CD pressing) on a professional level.

 

I am also a self taught developer and whilst I have never really worked on anything as low level as you do I love code and how things work. On top of this I am also a qualified electrician and have some minor qualifications in electronics engineering also. The whole problem and your solution really fit my interests like a glove.

 

Masters get passed between various different companies or departments for various releases and licences and it would not be common for the original master to be sent for obvious reasons. I feel that there is a large margin of error to be attributed to copy masters. A simple labelling error could easily cause DolbyA to be leaked into a manufactured product. It is unfortunate and I can 100% guarantee that in all but a few isolated cases this would not have been done deliberately. It would simply have been a case that the engineer who mastered the release for the final format would likely not have been the engineer who originally made the final mix master or production master. In fact the original engineer would likely not have heard the music again until after it was released to the public unless there was reason to do so.

 

eg. In the case of cassette, a master would be sent for production and the master would have then been transferred to a "loop bin" master (before the days of digital bins) by the factory engineer. If the incoming master (form the original mixing/mastering engineer) was not labelled the then the transfer to the, likely 1", loop bin master would not have been passed through Dolby. This of course could happen in reverse also where a master was incorrectly labelled as being DolbyA but was actually not and decoded inadvertently.

 

Of course the same principal also applies to Vinyl and CD and every other format, consumer or not (DAT copies, multitrack masters (where some tracks have DolbyA and some over dubs do not)). The whole thing is a minefield but one that needs highlighting at both a professional and consumer level.

 

I actually found your work as I felt I had a master, transferred from tape, that was not right at all. I was altering the EQ to some hellish levels to make it sound anywhere near reasonable. I decided that the master had been incorrectly DolbyA decoded and as a rough test passed the master through the recording stage of some DolbyA hardware to see if it made the master sound more like I expected it should (ie. I applied DolbyA to the muddy compressed audio). The difference although not right at all was like night and day.

Now I have not managed to get into this any further and I need to get the original tape (which is labelled DolbyA and has Dolby tones) transferred again, this time making sure it is without any Dolby processing so I can compare the sound. I highly suspect that the Dolby unit was either left in bypass after the tones were recorded or that the tape master in question is a copy master and was decoded when copied but with the tones remaining. Both of these possibilities could have resulted in the master not being DolbyA but then being decoded on digital transfer due the the tones and labelling, giving me this muddy mess to work with.

 

After finding your posts and software and reading the comments it also became apparent that this could have happened before on some items that have been released that I am associated with (not directly). I have seen comments from consumers in relation to items that are now under my control but were released in the 90's- early 2000s where the releases are slated for sounding thin and not at all like the vinyl. Now we both know that vinyl does have a unique sound and it was always the opinion that we only had what we had to work with and that the transfers from tape were what they were, so we had previously all but dismissed these comments as we felt that they had no merit, many of the releases were worked on by professional engineers but, of course they were not the original engineers and in may cases the recording artists were not involved in the re-release for various reasons. But.... leaked DolbyA would make sense so I am going to be investigating this is due course.

 

I am also open to that idea that some masters may be a mixture of DolbyA and non DolbyA tracks as this could easily happen when compiling a production master in the correct track order etc.

 

I am really interested in working with you in anyway I can on your decoder and I am also interested in how I may be able to obtain a copy of the "professional" version that is licensed to use all the command line switches etc. so I can really evaluate the added benefits vs DolbyA HW. Whilst my electronics knowledge is not at a level where I understand the technicalities in detail I do understand the basic principals of capacitance, inductance, reactance and impedance etc and I can at a very high level begin to imagine that a software solution will produce a cleaner and more accurate result than analogue processing ever could.

This got me thinking not only about degradation of electronic components in existing units but also how aspects such as operating temperature could alter the response of some components (especially older ones).

 

In conclusion I am 100% with you all the way and have a grounded knowledge of the inner workings of the record industry behind me at all levels. I would love to discuss things with you directly and would like to discuss the options relating to your "professional" version of the product.

 

I am not sure of the best way to contact you directly but I have found your profile on linked-in and sent you a message on there also, so maybe we could exchange details through the linked-in messaging system?

 

Regards

 

Calum

 

 

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I have just had a listen (only on an average set of headphones) and they do sound really clean. I will have another listen in the morning on some propper speakers and give you some feedback. 

 

Is there any chance you could add the FeralA source material prior to decoding so that it is possible to compare the source to the result?

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