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Gentle Giant – Golders Green 5/1/78

4 Feb


Recorded as part of the BBC’s year long quadraphonic tests in 1977/78 and broadcast as part of the ‘Sight & Sound’ simulcast series on BBC1 & Radio 1.

Release: DS71m

Source: Matrix HJ encoded DVD

Process: ‘Medusa’



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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