Fosgate Model 4

[Disclord]

Disclord,

From the patent:

The system is applicable to the decoded signals obtained from a simple matrix decoder using and 4-2-4 quadraphonic matrix encoding and decoding system.

The exact nature and details of the invention can be obtained from the following detailed description of the invention when read in conjunction with the annexed drawing in which:

FIG. 1 is a block diagram showing a preferred embodiment of the invention in a quadraphonic sound system;

FIG. 2 is a detailed showing of a suitable detector of the invention for application in an SQ quadraphonic sound system;

FIG. 3 is a detailed showing of a suitable detector of the invention for application in a QS quadraphonic sound system;

Please site a reference stating where Martin said the Tate DES would not work for QS as well as SQ. He never told me that.

You may speak of the IC's, which both Jim and Martin said had design flaws, but I was speaking of the Tate DES.

Yes, I was misunderstanding you.

And, yeah, the Tate IC's had some major flaws in them - but, sadly, for SQ, there is absolutely nothing else if you want accurate decoding. I, personally, think the best 'modern' decoding system (NOT for SQ) is DTS Neo:6 - Pro*Logic-II doesn't overwhelm me like it seems to everyone else - in fact, when I first heard it, I was kind of disappointed. Fosgate Six-Axis had been really amazing sounding and, to my ears, PL-II was a step backwards. And Circle Surround sounds like the Sony SQD-2020.

 

[Disclord]

I find it works better when splitting the bands, to just pass the bass 40Hz and below without decoding. This trick seemed like a no brainer to me when I was setting it up but I guess that was one of Fosgates inovations. The Fosgate model units use this approach. I think - but I'm not sure - that Digital Sevo Logic was Fosgate's improvement on the pumping artifact that DES had a problem with.

I've actually incorporated calibration in my experiments. You can do simple things like taking an impulse response of your signal chain and making an offset so that the frequency response is perfect. The easiest way I can figure to do it for vinyl playback is to get an audiophile pressing plant to press the phase and frequency test tones onto a piece of vinyl and then have the calibration offset inside the decoder itself.

And there may some faults in your logic about the SQ encoding/decoding. It seems like you base your opinion of the decoding on the differences in the encoding equation. This logic is based on the assumption that the matrix is a perfect inverting matrix. Most all 4:2:4 matrices used in surround sound are not perfectly inverting equations - you don't get out exactly what you put in.

Like what exactly? (and I don't mean that to sound sarcastic or anything - I want to know what you are refering to in what I wrote)

The decoding isn't, and can never be, a perfect inversion of the encoding matrix - it doesn't work that way for any N:2:N matrix and that is why adaptive decoding is required.

The Servo Logic was cool because the detector set the attack speed based on how 'far apart' the newly predominant signal was compared to where the system was at the present moment. Do you have Jim Fosgates interview with Reber in Widescreen Review? He gives lots of good info in that one even though Reber keeps bringing up the Tate.

With Jim Fosgate out of actively developing surround technology, there's no one with ties to the old-days anymore. Hopefully, we will never get new stuff like Circle Surround again!

 

[Quadzilla]

@:@:@:@:

 

[bmoura]

Do you have Jim Fosgates interview with Reber in Widescreen Review? He gives lots of good info in that one even though Reber keeps bringing up the Tate.

That's probably because he was partnered with Wes Ruggles in Ruggles-Reber Productions, back when they were recording music for release in SQ encoded form to promote the Tate chips !

 

[Key]

Disclord. I think I was referring to you saying that *only* an SQ decoder would decode SQ properly. To me that whole idea sort of negates the need for logic in the first place. If an SQ decoder was the only thing that worked on SQ material then you wouldn't need a logic/adaptive system at all. The way I personally think of adaptive/logic matrices is that they are actually variable matrices.

Also with digital you can incorporate a variable phase control that would allow you to change the setting to decode pretty much anything you would want to. If you want SQ just set the phase for SQ, if you want EV-4 then just swap the phase for EV-4 etc...

I agree that CSII is just weak. But I have heard some implementations of Neo 6 that just sound down right horrible - fidelity was ripped to shreds. And just because you don't like CSII I wouldn't go making blanket statements about all new technologies.

 

[Tom 11114056]

I was outbid for the last Model 4! Drats... I will keep plugging away.

I found one at an estate sale today.
Unit has remote but no owners manual.
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