Matrix Decoder Demo Disc?

[Disclord]

Hey everyone on QQ,

I've been thinking of making a DTS CD that would be made available to all QQ members - it would be a 'demo disc' of various matrix decoders, both music and film. So it would have the Fosgate Tate II 101A, Sony SQD-2020 - and if someone with the Audionics Space & Image Composer could run the test tracks through it and encode it at the DTS CD rate, we'd be able to compare the Audionics with the Fosgate - my Lafayette SQ-W is in Albuquerque at my parents house so I don't have current access to it, so someone with that decoder could maybe encode its results too - and anyone with a Front/back logic SQ decoder. Or a decoder based on the Motorola Full-Logic chip set. The Fosgate Tate II can be set to have no logic action at all, so the disc would include true non-logic SQ decoding as well.

Plus, while I don't have a Type-A QS decoder, so maybe someone with a QSD-1/2 or the 1000 or a receiver with the Type A Vario-Matrix could run a track for it - Pink Floyd's Money is the track I think I'd use for both SQ and QS tests since its available on the Hi-Fi News Quadrafile test LP. I don't have the LP but and I have Money from it in both QS and SQ versions as well as the position and 'glurg-glurg' logic tests. I have the BMX/UMX versions of Money and position/logic tests too, but no access to a BMX/UMX decoder. Since Money is on that wonderful bootleg DVD-A, I would include that as the "gold standard" for comparison.

Also, a selected stereo track could be processed through the "Surround Synthesis" modes of the various decoders and encoded in DTS for the CD to compare synthesis results.

For films, I'd use my Shure HTS-5300 and HTS-5000, plus Circle Surround, Neural, DTS Neo-6, PL-II and Pro-Logic. I have a Pro-Logic decoder with the original Sanyo chip that Dolby used in their CAT-150E theater decoder cards and I also have an Audiosource Pro-Logic decoder that uses the last Analog Devices SSM-2125 PL chip that was so widely used in consumer equipment as well as the Dolby CP-45 theater processor and SA10 Surround EX theater adapter. I'd also use the Fosgate Tate II's "Movie" mode in the movie comparisons. If anyone has the Aphex ESP-7000, AVM-8000 or the Proton SD-1000, we could include those results - Surround Sound Inc also made some logic-based decoders - their first, the 720 was an Aphex design, but their last was an in-house logic design they called "Movie Logic" - I believe it was a true cancellation design and not a gain-rider.

Since the Dolby MP Matrix encoding and decoding changed in 1979, I think an early Dolby Stereo mixed film, such as Saturday Night Fever, which used the QS matrix only for encoding the mono rear channel (Dolby encoded the fronts separately and 'added' the surround encoded track to the 2 channel mix), should be also decoded through all the film decoders and also ran through the QS Vario-Matrix decoders too. The MCA DiscoVision disc is a direct-from-35mm stereo transfer from an original Dolby Stereo print, so I'd use that since it hasn't been re-encoded with Dolby's modern encoders (like Star Wars and other films have)

I haven't decided which track should be used for the 'main' movie decoding or the surround synthesis tests.

I can't encode DTS DVD's - I'll be using the Creative DTS-610 stand-alone encoder that uses the 1.4mbps, 44.1k CD encoding rate, so it will be a audio-only disc - which is probably good because there's no picture to distract from the decoding.

Are there any ideas for stereo synthesis tracks, movie selections, SQ encoded selections, etc... besides what I've mentioned? I want your thoughts on this. It could be a really cool disc - and if anyone has one of the super rare decoders like the Scheiber 360 Spatial Decoder for SQ or CBS Paramatrix, it could be a really amazing disc to get to compare all the various decoding methods - it's just too bad there was only 1 Shadow-Vector prototype that doesn't exist anymore (it was never really finished anyway) - or that none of the original discrete circuit Tate DES prototype decoders still exist.

Does anyone have that non-logic Audionics "audiophile" SQ decoder? It's shown on the CBS SQ LP inserts - it had precision 6 or 8 pole phase-shifters (I can't remember if it was 6 or 8 pole) and was meant to be connected to the Tate DES when it became available. In fact, it was supplied to Audionics by Tate Audio.

Is this a good idea or just a dumb one all around?

 

[Quad Linda]

Disclord, you are a God!

Linda the donnamatrix

 

[quadsearcher]

This is a very good idea. Tab's 'scope patterns of Chase are very cool and do show some analysis, but I've wanted to hear a decoder "shootout".

 

[Disclord]

Chase is a good quad demo, but it is 'square' quad, just the four corners - and quite simple for even Power Transfer (full wave-matching logic) decoders to decode correctly since, during the opening, there are no other instruments or echos/reverb present in the other channels - simply shutting off the 3 channels not in use will provide correct decoding. I want something (which is why the test tones and "Money" track from the Quadrafile LP are my first choice) more complex, that has phantoms, not only in the center front, but center sides, center back (rare for SQ since CBS discouraged it) and center of the room (the SQ Carpenters recordings might be good for that one since Karen's voice was placed dead center of the room)

The soundtrack to "Annie" - especially "Hard Knock Life" might be good - it was encoded with the CBS Position Encoder from the multitrack masters and not a 4-channel quad mixdown, thus all locations used are correctly encoded. I might have to use snippets of different recordings - such as Funny Girls "You Are Woman..." to get things like Center Back decoding tests - the CBS SQ test LP has Center Back, but again, like the Chase, it's by itself, without other sounds in other channels to challenge the logic and its placement of the predominant sound.

One other thing I thought of for decoders - the various Fosgate models, from the DSM-3601 to the last Citation model with Six-Axis decoding. I had a Fosgate DSM-3606 that I HATED since it didn't remove L/R Front from the surrounds - but their other decoders did - and had various 'surround' modes for music to create a wrap-around effect. I think the full "wrap around" stereo synthesis is the only mode to use on decoders with various synthesis modes - that way, it's a level 'synthesis' playing field, not comparing full surround synthesis to a 'hall' mode.

That's why I'm posting - to find people who have various decoders that I don't have access to and also can do the decoding/dts encoding themselves to be included on the disc, plus to come up with ideas for test tracks and such that will challenge the decoders so that listeners will be able to really hear what each can do.

And to those without a bunch of decoders or DTS CD encoding ability, I want/need your input too on ideas for test tracks, etc... I'd like this to be a QQ community project - I don't want anyone to feel left out or that their favorite decoder wasn't given a fair shot.

I wish someone had a CBS Position Encoder so we could make our own 'torture' tracks - like different voices coming from the 8 cardinal SQ directions, or multiple sounds/voices slowly changing position - like two different voices exchanging places from left to right or diagonally. Unfortunately, I don't think I've ever even known anyone with a Position Encoder. Only CBS made the one model and its the only encoder that can encode every direction, including the 'interior' positions, with no errors or cancellations upon stereo or quadraphonic playback, unlike the standard 4/2 SQ code. Dan Gravereaux, co-inventor of SQ, doesn't even have his anymore. If we had a Position Encoder, think how cool it could be - QQ members could read some predetermined text and record their voice; we'd encode it to SQ with the Position Encoder, and show the encoding "map" on the forum of who's voice went where in the quad soundfield and where it moved to (if it moved). And unlike the days when Quadrafile was made, there would be no problems with phase shifts causing errors - phase errors on the master tapes were a big problem back in the quad days. So the custom SQ test would be perfectly encoded. But, that's all a nice dream because Position Encoders seem to, sadly, not be around anymore. I don't think Gary Reber even has the one he used to encode the David Bowie, Dolly Parton and Buddy Rich LD's anymore. I might write him and ask - I don't know him but he was involved directly with Tate Audio and used to mention SQ a lot in Widescreen Review - does anyone on QQ know him personally?

 

[dgreen]

Great idea. I commend you and commison you to proceed!