Quadraphonic decoding in virtual

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Would you buy a (good) virtual quad decoder/demodulator for PC or Mac?

  • Could take it or leave it.

    Votes: 0 0.0%

  • Total voters
    23

atomheartquad

New member
Joined
Aug 25, 2003
Messages
4
Location
Australia
Hi Quaddies.

Some time ago I made noises about quad decoding software for PC.
Since there was nothing out there, I thought it a good idea to make one.
And why not?

I'm pleased to say the project is still alive and well.
The reason for the delay has been mainly due to time constraints and finding a programmer who not only understands professional audio, but is available and is actually interested in quad. All of these issues have finally been addressed.
What's more is that we happen to work for the same company www.sound-music.com
We design, build, export and import professional audio gear. How's that?

The first area to be tackled is SQ.

We have access to some wonderful hardware as well for testing, analysis and comparisons. Scheiber (one of 35 ever built, apparently), Fosgate Tate-II 101A , CBS SQL-400A, Audionics (?), Sony, JVC, Pioneer and many others.

However, we need some more information. In particular, schematics, parts lists etc to some of these units. if anyone out there can help, it would speed things up. Obviously the Fosgate 101A Tate-II will be of main interest for SQ.
Wonder if Jim's up for it?

The final product will probably take the form of a Direct-X or VST type plug-in that can run inside a host program, like Nuendo, Pro-Tools, Cubase, Wavelab-5, Logic Audio etc although a "stand-alone" is not out of the question.

We will also look at the QS and CD-4 formats in due course.

The physical inputs and outputs can be handled by most multi-channel i/o soundcards and audio interfaces. For CD-4, however the A/D would need to be 96khz to allow capturing the 30khz carrier. Once in virtual, it should also be possible to compensate for worn or weak carrier signal by using supersonic e.q and noise reduction techniques.

As this project is not subsidised in any way, it’s at this stage really a “labour of love”. However, this may change as things develop.
The end price is impossible to guess at this stage, but we’ll keep the end cost as low as possible. (Just as long as it pays for an Aston Martin V12 Vanquish (with a surround system)).

But jokes aside, we would like to know how much interest there is out there for this kind of “virtual device”.

Let’s see how far we’ll get.
So, who’s up for one?

Do the poll, man.
 
Last edited:
I have put a tick on your poll
I live in Melb.VIC
And would be interested in your quest
I have all of the decoders that you mention
plus others
You can ring after 7 pm
any night
03 97234837
Ron
 
Hi Atomheartquad,

most SQ-decoder schematics with Motorola chipset were built around their application in their datasheet.

Look here:
http://www.datasheetarchive.com/download.php?pi=282229

(The security code is given above the input field, you have to type it in in order to download the datasheet.)

I have other schematics of SQ, mainly hobby electronic projects. One seems to be from a Sony device. But they are German language.

A "project" I'm working on is the service manual for my Grundig standalone CD-4 decoder transfered to pdf-format. Again German, but with schematics. Includes Signetic's CD4-392 (holy grail).

-Kristian
 
I have the Sansui QSD-2 schematics and service manual as a PDF file if you want that, you will then get a head start with QS decoding. The schematics for Tates and Audionics S&IC will be more difficult to obtain, but Ralph (The Quadfather) is in contact with Steve Kennedy regarding the S&IC information (see posts in another thread). It is close enough in design to the Tate 101, so should be fine. The Tate 101 and Audionics S&IC use cancellation techniques, unlike the majority of "normal" decoders using gain riding where image shift and "pumping" is a problem. The Sansui varied the matrix co efficients, with modest gain, could perform very well. See here for a set of matrix decoding equations.

http://www.mtsu.edu/~dsmitche/rim456/Quad/Quad_Formats.html

Cheers

Malcolm
 
Last edited:
rustyandi said:
I have put a tick on your poll
I live in Melb.VIC
And would be interested in your quest
I have all of the decoders that you mention
plus others
You can ring after 7 pm
any night
03 97234837
Ron
Hello again Ron. We hope to do some preliminary testing of the software in the coming weeks and if we may, also use some of your wonderful gear as reference.
By the way, do you have any schematics for any of them?
I look forward to seeing you and your lovely wife Lorraine again soon.
I have also sent the Abbey Road DVD-A to Warren for audition and firmware test.
Keijo.
 
krkier said:
Hi Atomheartquad,

most SQ-decoder schematics with Motorola chipset were built around their application in their datasheet.

Look here:
http://www.datasheetarchive.com/download.php?pi=282229

(The security code is given above the input field, you have to type it in in order to download the datasheet.)

I have other schematics of SQ, mainly hobby electronic projects. One seems to be from a Sony device. But they are German language.

A "project" I'm working on is the service manual for my Grundig standalone CD-4 decoder transfered to pdf-format. Again German, but with schematics. Includes Signetic's CD4-392 (holy grail).

-Kristian
Vielen Dank Kristian

We will sift through the info with a fine tooth comb.
The Grundig CD4 schematic sounds interesting.
I'd love a copy. Ich kann Deutschen lesen.
Let's stay in touch.

Keijo
 
Malcolm2010 said:
I have the Sansui QSD-2 schematics and service manual as a PDF file if you want that, you will then get a head start with QS decoding. The schematics for Tates and Audionics S&IC will be more difficult to obtain, but Ralph (The Quadfather) is in contact with Steve Kennedy regarding the S&IC information (see posts in another thread). It is close enough in design to the Tate 101, so should be fine. The Tate 101 and Audionics S&IC use cancellation techniques, unlike the majority of "normal" decoders using gain riding where image shift and "pumping" is a problem. The Sansui varied the matrix co efficients, with modest gain, could perform very well. See here for a set of matrix decoding equations.

http://www.mtsu.edu/~dsmitche/rim456/Quad/Quad_Formats.html

Cheers

Malcolm
Thanks for the info Malcolm.
The QSD-2 schematic could come in useful. Can you send?
use: [email protected]
I shall also consult the Quadfather re S&IC.
I came across the www.mtsu.edu link in my preliminary searches and is very useful indeed.
 
I'd be more interested in Matrix Encoding software for Mac so I could remaster my music for QS. I'd buy that in a second!
 
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