Dragged back to mathematical work….Screaming

2 Feb

After adapting the EV-4 decoding process to include H.O.P. i felt that i’d had enough of working on these matrix systems and decided that enough was enough.

That was until a conversation with a pal over the pond with regards the BBC’s second quad matrix system got me trying out its possible compatibility with the early Ambisonic system 45j, which actually proved not to be the case.

The problem with stating it’s not compatible is you need to prove it, so i created a basic decode process to check, which actually ended up becoming a full-blown process.

Like it’s slightly older brother, Matrix HJ has proven to be the nightmare it promised to be, but it’s finally done, and it includes H.O.P. That means there will be no upgraded version in the future as it’s the first decode process to be the best decode from the start.

To ask a question before it’s asked, what of Matrix H and any chance of an upgraded process?

The answer is a tentative ‘yes’.

Recently some information has been received that the Matrix H test broadcasts were complicated by the encode process being altered during the test phase, which was actually only until September 1977, which was when work on Matrix H was stopped in favour of its replacment, Matrix HJ. Although the difference is small, it’s enough to complicate the process of accurately decoding it, therefore needing two different versions of the process depending on which of the encoders was used on what material.

To further complicate matters, there is no list of which was encoded by which version, so it’s going to mean a method of deciding which version of Matrix H was used needs to be created.

Another issue that has arisen with both H & HJ is that most of the available recordings are ‘off air’, normally done on cassette decks. This further complicates things as both systems H & HJ are intolerant of phase/azimuth errors, making a decode almost impossible.

So, in an effort to ‘rescue’ these recordings it’s also going to need a process to enable the possible repair of these recordings, plus it may need reduced versions of the decoding process’ to enable a clean enough decode to be made.

That’s quite a bit of work still to be done to get the BBC’s two matrix systems from their year-long test transmissions in 1977/78 to a point where we are with the other systems.

This will be undertaken ‘as and when’ time allows, there is another project that is long over due and needs to be done, all i’m waiting for is some new hardware to arrive any day now, then its going to be full steam ahead.

What is it? I’m afraid you’ll have to wait and see. A couple of people know what it’s to do with, but at this moment in time the whole project is in my head, theoretically it should work… and we all know what happened to theory!!!

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17 Responses to “Dragged back to mathematical work….Screaming”

  1. beukenoot February 9, 2017 at 19:37 #

    Does the BBC have the originals in their archive, or was it all live?

  2. beukenoot February 9, 2017 at 19:36 #

    How did people listen to this BBC stuff, when they fiddled all time with the matrix?
    Well, in stereo but I meant those who had equipment for quad :)..

    • oxforddickie February 4, 2017 at 14:24 #

      Indeed, but there may be many who little to nothing of the battle between the systemsm and it did get heated!

  3. Owen Smith February 3, 2017 at 09:41 #

    I think it’s clear from these decode processes that Matrix H and HJ could never have been commercial successes. They’re too complicated to decode, late 1970s hardware would never have managed it. And this was all driven by a desire for a mono compatible quad matrix for radio broadcasting. SQ was great for broadcasting on FM stereo, except when the listener had a mono radio.

    • oxforddickie February 3, 2017 at 09:55 #

      I agree. It’s probably best to think of those broadcasts, and the Beeb’s extensive research into quadraphonic broadcasting, as being as being an essential part of what became UHJ, perhaps the ideal broadcast surround system.

      But as a matrix system meant for broadcasting and media use? No way!

  4. zaphod2359 February 2, 2017 at 23:40 #

    Wow. I’m always amazed at the complexity of these processes. I’m reminded of the saying that genius is the capacity to take infinite pains. Certainly makes my brain hurt! Sounds like you relish the challenge! I hope it comes out to your liking!

    Dave

  5. Owen Smith February 2, 2017 at 21:39 #

    I just wish I knew as much about audio and decoding as you do OD. Look on the bright side, you may be screaming but at least it shows the little grey cells are still working.

    So are we likely to see an HJ release soon? It sounds like it’s ready to go for phase/azimuth stable sources ie. CD and maybe LP.

    And have a well earned cup of tea, sounds like a break is in order.

    • oxforddickie February 2, 2017 at 21:43 #

      That is true, although in the great scheme of things it doesn’t help on a personal level… Sigh

      Oddly there are a few more ‘HJ’ items available that there are ‘H’. I’ve been using a couple of albums during the testing/listening period, one for each blog, and they are decoded and just need the iso’s and art work to be done.

  6. bayards February 2, 2017 at 21:08 #

    OD….great news. I lnow you have a few of my cassettes i sent you a few years back (Genesis, Richard III play etc). Be great to hear them one day. Fingers crossed

    • oxforddickie February 2, 2017 at 21:49 #

      Indeed, have not forgotten, the box is in the room, safe. Of course, being cassettes it’s a case of possible/maybe, and that’s once/if i can do something to over-come the errors using cassettes.

  7. sacdtodvda February 2, 2017 at 21:03 #

    Congratulations on the breakthrough, OD!

    Now more than ever I wish I had a good contact at the British Library Sound Archive to liberate the Genesis Knebworth 78 show they hold.

    • bayards February 3, 2017 at 14:59 #

      I think that is one of the cassettes i sent to OD.

      • oxforddickie February 3, 2017 at 15:08 #

        Yes. Both Carl and myself are well versed in the issues of attemptiung decodes with the likes of SQ & QS, which is often not possible to do, so with the some what horrendous phase issues that H/HJ have it’s hard, at this moment in time, to imagine quite how successful a decode will be is going to down to whether i can figure a way of actually creating a method of performing azimuth correction well enough to make any form of decode feasable.

  8. ceplaster February 2, 2017 at 20:30 #

    Best of luck! From my own experience, it can be a pretty painful rabbit hole to dive into.

    • oxforddickie February 2, 2017 at 20:46 #

      I’m about to send to a track to listen too, a bit tardy on my part, sorry

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