The rebirth of a 4DD-5 ptII

24 May

Have finally completed the work on both sides of the main pcb, the cables are still disconnected awaiting the new ‘sub-board’, which i will start working on today.

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Enoch Light – 4 Channel Demonstration

22 May

The fourth and final AM release

Enoch Light – 4 Channel Demonstration

Dynaco 4-Dimensional Stereo Demonstration Disc

18 May

Dynaco 4-Dimensional Stereo Demonstration Disc

Vanguards first demonstration disc, which was later reissued in SQ, although slightly altered

EV-4: The Mystery Solved? – Part II

16 May

Something i should have added in the first part of my investigation is that not all of the ‘QD’ releases are subject to having been released in EV-4 and QS formats. The last EV-4 encoded release appears to have been 5051 (Enoch Light – Big Hit Movie Themes) so it’s fair to say that any album from 5052 onwards marked QD is QS.

Now i will attempt to show how it is ‘possible’ to distinguish an EV-4 encoded album from a QS one, although i must state that when it comes to QS encoded albums the pictures may not be so clear cut, the visual phase response is just a snapshot of a rather complex mathematicalĀ  equation, so if you attempt to try this method yourselves, please take your time! Hopefully you’ll see why.

Unfortunately i don’t have more than one copy of any of the Project 3 quad albums so i’m unable to show how a particular albums visual phase response difference compares between the two, but i’m sure that the two albums chosen will give an adequate picture, so to speak.

We’ll start with one of the demonstration albums that were only released using EV-4. This is the album i released a few days ago, ‘Enoch Light – 4 Channel Stereo’. The first picture shows the standard waveform of the complete album that was used for decoding purposes, and included on the release.

The next view is a snap shot of the waveforms spectral phase. It would be very easy to take too much notice of this as it only shows a visual representation of what the program sees and isn’t truly correct, but for the purpose of this experiment it will be more than adequate.

As you see, there is a large amount of zero phase information on almost every track, surrounded by large amounts of random phase information, including some small amounts of out-of-phase information on a couple of tracks.

This could be considered fairly standard for a stereo album and normal for an Amplitude Matrix system like DY and EV-4. As will be seen later, there is no evidence of any +-90 degree information above or below the zero degree line.

Now for the next album marked QD, which is ‘Tony Mottola – The Best Of’

and its spectral phase

I’m sure that you’d agree the difference is instantly obvious, there being less ‘random’ phase information and a slightly lower level of zero phase information. But more importantly there is evidence of +90 degree information on two of the tracks.

Although it is QS encoded, due to the way the audio is encoded and this being just an overview snap shot, there is no guarantee that there will always be such marked proof as shown here. Closer examination by expanding the view horizontally per track would probably show up smaller groups of ‘information’ on either the -90 or +90 degree line.

Because of this it’s not advisable to go by just one track from an album, but at the bare minimum one half of it, preferably the whole album.

To endĀ  i’d like to re-emphasise that this issue is probably why many state that their ‘previously thought to be EV-4 album’ decodes perfectly well through a QS decoder is because it is QS.

The program i have used is Adobe Audition 3, which was once a paid for programme but has, in the last few years, been officially available as a free download. To save having multiple links i’m making the whole package (including updates) available.

 

EV-4: The Mystery Solved?

15 May

One of the most annoying rumours that has seemingly stuck like glue with the quadraphonic community is that the AM systems DY & EV-4 are compatible with the PAM system QS.

Like a lot of these things that have become ‘accepted general knowledge’ there was a point where it all started and after 48 years, and there having been no obvious sign of anyone looking it the what, where and why’s of it, i felt it was another of the quad ‘myths’ that needed slaying once and for all.

It actually wasn’t hard to find a lead to how it all started, and for those that have a collection of ‘Project 3’ quad albums, i have a question for you.

Have a look at the record labels and you’ll probably find you have one or more where the record number ends with either: QD, SQ OR CD-4. I very much doubt anyone has a copy that actually ends in QS.

But Project 3 did release albums in QS. So what’s the deal?

As we all know, Project 3 were the only label that released many of their quad releases using one or more of the commercially available systems, many being made available in all four. So where does this leave the QS copies.

When originally sold, the system the record was in had a label stuck on the cellophane announcing which it was, but once that was removed the only way to normally tell was via the record label, and as you’ve possibly found, there are no labels with QS on them.

A simple-ish test has proven that a couple of half a dozen albums i tested were in fact QS, even though the label stated QD, the others being EV-4, as you would expect with the label stating QD.

The label originally started releasing quad albums when the EV-4 system was released and included the other systems a year or so later when they were released. It’s obvious now that instead of starting to use the QS prefix for QS encoded albums, they continued using QD, only changing when SQ came onto the scene.

I’m guessing this is where it all started. Whether it was by mistake, or some misguided idea, i believe this is soley responcible for the idea that the two systems are ‘compatible’.

This does leave those with a collection of Project 3 quad albums that are marked QD unsure whether they are EV-4 or QS. Well there is a way of telling, but it’s ever-so slightly technical, so i’ll leave it for another day to show you how to tell them apart.

 

Harmony For Elephants

15 May

Somewhat off the blogs normal course, i’d like to bring this release to the memberships attention

Harmony For Elephants

 

The re-birth of a 4DD-5

13 May

Having previously mentioned that i’ve started to (finally) modify one of my JVC CD-4 demodulators, i find the modification has turned more into something of a redesign, so whilst waiting for even more parts to arrive to allow continuation work on the main board, as well as an additional sub-board, i thought i might do a pbotographic record of how it goes.1526201814030-1128117357

Of course, whether it works or not….. Lol

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