DY & EV-4/Stereo-4 Reference Decode Series

7 May

As part of the close-down of the blog i’ve been promising to release a small number of the demonstration records from the 1970’s for each of the major Quadraphonic matrix systems, which will include not only a decoded version of the album using the last of my decoding process’s, (the **d series) but also the original encoded stereo file on the DVD-A portion to allow comparisons between different methods of decoding that particular matrix system.

To start the ball rolling i’m starting with one of the two Amplitude Matrix system’s  (namely DY & EV-4/Stereo-4). Unlike the later systems SQ, QS etc, they were developed before the use of 90 degree phase shifting, so were quite basic and limited in what could be expected from them.

Firstly, it is/was impossible to decode the four channels back to their original positions using hardware decoders, instead the decoders were programmed to “create an effect” giving about 1db of rear left and right separation. This meant the encode and decode equations were completely different, something that didn’t happen once 90 degree phase came into use.

There has been much spoken about a QS decoders ability to actually decode the two AM systems, but that normally comes from those whose knowledge of matrix systems is either seriously limited or non-existent.

It does appear that most people are more than happy with some noise coming out of the rears, irrespective of whether it’s right or not. It’s more than likely the major reason why people believe they are hearing it as decoded is down to phase.

I’ve yet to read, or hear, of anyone who has gone near the subject, most probably because they a) have a good reason not to and/or b) they just don’t know.

So what do i mean? QS is, as i’ve previously mentioned, one of the Phase Amplitude Matrices, using +-90 degree phase shifting to enhance the encode/decode process. Of course, like anything matrix encoded, QS encoded material requires the inverse of the encode equation to be used during decoding, a part of which means the rears are shifted back to their original phase.

And here’s the rub. By attempting to decode DY or EV-4/Stereo-4 through a QS decoder, as well as being mathematically incompatible, the resulting rear channels are no longer on phase in releation to the front channels. Those who have heard the effect of out of phase speakers when setting up a stereo system will be well aware of the illusion of increased channel separation and space can becomes apparent, but that’s all it is, an aural illusion.

So, as well as making available these demonstration albums, i’m also making available a small script for those who use Adobe Audition v3 to allow correction to the rear channels to bring them back in phase with the fronts after using a hardware QS decoder.

This script is supplied ‘as is’, it makes no attempt to do any form of decoding, just correction. It is very small and ONLY for use on the rear channels of DY or EV-4/Stereo-4 material after being ‘decoded’ by a hardware QS decoder. I offer no help with this script, or in the use of it with Adobe Audition v3, or anything involved with Adobe Audition.

So, to the first of the three EV-4/Stereo-4 and one DY demonstration albums i plan to release:

Enoch Light – 4 Channel Stereo (EV-4/Stereo-4) New v2

Reference Series Releases contain:

Original EV-4 encoded Stereo file for personal decode evaluation (MLP only)

EVd decoded versions on MLP, DTS,AC-3

 

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9 Responses to “DY & EV-4/Stereo-4 Reference Decode Series”

  1. gjwAudio May 10, 2018 at 22:47 #

    Thanks so much OD for getting off yer ___ !
    Reminiscent of the excitement in the “olde days”, when you would pop up an unexpected release.
    I hope your health is improved and you are enjoying Life these days.

  2. Skrain Dukat May 9, 2018 at 13:00 #

    i think the stereo tracks are empty

    • oxforddickie May 10, 2018 at 06:42 #

      Have just checked and there does appear to be an issue with the stereo track on the DVD-A section.

      I’ve sorted the problem, created a new image and it’s now available using a new torrent available on the post. Sorry about this Boo-Boo

  3. jaypfunk May 8, 2018 at 13:15 #

    Thanks OD!!

  4. forthosewithfourears May 7, 2018 at 21:43 #

    Thanks for this Richard – downloading (BitTorrent) right now.

  5. Owen Smith May 7, 2018 at 18:47 #

    Did you realise you uploaded the .torrent file inside a .rar file? Not the end of the world, but a bit of a pain to deal with given .rar files are one of the less standard packaging techniques. I unpacked it using GoodReader app on my iPad of all things, my only other tools for rar files being Windows command line ones.

    Anyway, thanks for this. About a year after the blog started to shut down, but better late than never :-).

    • oxforddickie May 7, 2018 at 19:21 #

      Yes, it was deliberate, i didn’t want the possibility of multiple downloads of a torrent file being flagged up somewhere. Sorry for the problems, will try to remember to zip it next time.

      As to the delay, yes it has taken a very long time to actually start on this, the files were done late last year but the issue was actually creating a disc iso, doing such things have been very low on the ‘things to do’ list, the only reason i got off my arse was to help fill the gap whilst The Captain is recuperating.

      One positive of me finally finding the get-up-and-go is that the CD-4 demodulator is now ‘almost’ upgraded, just waiting for more parts for another modification i thought of to arrive in the next day or two. If it all works as i planned who knows what could appear as a one off………

  6. avpig May 7, 2018 at 17:06 #

    Yay! Thanks!

  7. oxforddickie May 7, 2018 at 15:31 #

    Although this release uses a torrent to enable download, it does not use a tracker so it is essential that, at the bare minimum, DHT is enabled in your client.

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