How does Dolby Pro Logic material sound when processed by Sansui QS?

[Kreshna]

You have an old DVD player playing a Dolby Pro Logic (Dolby Surround) source material, channeled through the player's L and R analog output (Dolby Pro Logic signal is always matrixed into stereo). You then connect the player's L/R output into a Sansui QS' L/R stereo input. This way, the Dolby Pro Logic matrixed signal is processed using Sansui QS instead of a proper Dolby Pro Logic pre/pro.

How would it sound? Will it better? Will it worse? Will it basically the same? I'm talking about early Sansui QS here, like Sansui QS-1 and Sansui QS-100, instead of the more sophisticated Sansui QR or QRX (vario-matrix).

 

[Grenadeslio]

Don't know about the Sui, but my Lafayette LA-975 in discrete mode really works great, much more out of the rear channels. Much closer to more modern discrete surround only no center channel. Only tried it for shits and giggles though, never really ran it that way.

 

[Duane]

You have an old DVD player playing a Dolby Pro Logic (Dolby Surround) source material, channeled through the player's L and R analog output (Dolby Pro Logic signal is always matrixed into stereo). You then connect the player's L/R output into a Sansui QS' L/R stereo input. This way, the Dolby Pro Logic matrixed signal is processed using Sansui QS instead of a proper Dolby Pro Logic pre/pro.

How would it sound? Will it better? Will it worse? Will it basically the same? I'm talking about early Sansui QS here, like Sansui QS-1 and Sansui QS-100, instead of the more sophisticated Sansui QR or QRX (vario-matrix).

Do you have the Sansui?

 

[Kreshna]

Do you have the Sansui?

I do not, that's why I asked.

It's kinda long story. I'm also a retro computer enthusiast; building DOS-based and Windows 98-based retro computers to play old games. Most PC sound cards from the era were quadraphonic sound cards, like Diamond MonsterSound MX300 (Aureal 3D) and SoundBlaster Live! I'm using a Diamond MX300 on my Pentium III system, by the way. The sound card has quadraphonic output instead of 5.1, and I'm controlling the volume using a Technics SH-AC500D, which acts as passive volume control for the quadraphonic sound card. I only use four of the SH-AC500D's 5.1 analog inputs.

I imagine a Sansui QS processor would make better "passive volume control" for my quadraphonic Diamond MX300 sound card. Not only a Sansui QS has quadraphonic input, but it also has stereo input, where it would upmix stereo sources into quadraphonic using the QS matrix. The SH-AC500D, on the other hand, cannot upmix analog stereo sources using its Dolby ProLogic; it could only apply Dolby ProLogic into its S/PDIF input.

So, a Sansui QS could be an ideal preamp for my retro computers. It would act as volume control for my quadraphonic sound cards (like Diamond MX300), and it would also upmix my stereo sound cards (like Sound Blaster AWE64) into quadraphonic sound.

However, certain computer games were mixed with Dolby Pro Logic. Examples are WarCraft III and Assault Rigs. I wonder how such natively Dolby Pro Logic games would sound when processed by Sansui QS instead of a Dolby Pro Logic processor.

 

[Duane]

It's hard to believe that the decoder in the Sansui would be able to decode the Pro-Logic encoded matrix, especially the center channel information. This is important because with Pro-Logic decoders, you can deselect the center channel and that information is channeled to the front left and right. But I don't think this is capable with the Sansui's decoding. So you'd not be getting center channel info and it would not sound right.

 

[sKiZo]

Maybe I'm confused here, but ... the dolby has already been decoded when it hits any of the outputs of the player. That (now standard) stereo output would be handled by the QS decoder exactly the same way as any other stereo source, decoding true QS encoded material into four channels, and winging it with any stereo input that isn't encoded. Running unencoded material through the QS decoder will certainly give you four channels of output, but the results will vary - mostly decent but some weirdness possible as it won't have the control signals it requires to track and rearrange the output as the Sui Gods intended. Typical problems might include motorboating, ping ponging, and inconsistent volume.

 

[Duane]

Maybe I'm confused here, but ... the dolby has already been decoded when it hits any of the outputs of the player. That (now standard) stereo output would be handled by the QS decoder exactly the same way as any other stereo source, decoding true QS encoded material into four channels, and winging it with any stereo input that isn't encoded. Running unencoded material through the QS decoder will certainly give you four channels of output, but the results will vary - mostly decent but some weirdness possible as it won't have the control signals it requires to track and rearrange the output as the Sui Gods intended. Typical problems might include motorboating, ping ponging, and inconsistent volume.

Where did you get that information that Dolby Surround or Pro-Logic is decoded in players that have just a stereo analog out or a digital out? Dolby Surround and Pro-Logic is decoded in the receiver or processor from the analog stereo outputs or digital outputs from whatever source that has it encoded.

On the other hand, players that have multi channel outputs, then the player can do the decoding (if it's set up to do so) and send it over the analog outs.

 

[Grenadeslio]

Exactly right, the discrete quad is decoding from the stereo signal just as the surround processor is. But here's the rub, because multi-channel exists in the recording the quad systems of the day are able to extract the separate signals In a way that's actually (more?) discrete than actual surround. Bullets definitely fly during gunfights, planes roaring overhead, very realistic but to the point of being distracting from the video, it's actually tooooooooo much, at least for my taste.

 

[Kreshna]

Exactly right, the discrete quad is decoding from the stereo signal just as the surround processor is. But here's the rub, because multi-channel exists in the recording the quad systems of the day are able to extract the separate signals In a way that's actually (more?) discrete than actual surround. Bullets definitely fly during gunfights, planes roaring overhead, very realistic but to the point of being distracting from the video, it's actually tooooooooo much, at least for my taste.

As expected. It seems a quad system would do a better job of extrapolating rear channels from plain stereo. But how about specifically-encoded Dolby Pro Logic source materials?

It's hard to believe that the decoder in the Sansui would be able to decode the Pro-Logic encoded matrix, especially the center channel information. This is important because with Pro-Logic decoders, you can deselect the center channel and that information is channeled to the front left and right. But I don't think this is capable with the Sansui's decoding. So you'd not be getting center channel info and it would not sound right.

Indeed. Dolby Pro Logic has different matrix than that of Sansui QS. I wonder how the sound would be like.

 

[Grenadeslio]

As expected. It seems a quad system would do a better job of extrapolating rear channels from plain stereo. But how about specifically-encoded Dolby Pro Logic source materials?



Indeed. Dolby Pro Logic has different matrix than that of Sansui QS. I wonder how the sound would be like.

Exactly right, the discrete quad is decoding from the stereo signal just as the surround processor is. But here's the rub, because multi-channel exists in the recording the quad systems of the day are able to extract the separate signals In a way that's actually (more?) discrete than actual surround. Bullets definitely fly during gunfights, planes roaring overhead, very realistic but to the point of being distracting from the video, it's actually tooooooooo much, at least for my taste.

I'm talking about multi channel movie soundtracks, either from the two RCA outputs on the cable box etc, or the RCA outputs on a DAC. If you have something else in mind please enlighten me.

 

[the skipper]

Dolby Stereo/Dolby Surround/Dolby Pro Logic is a matrixed tech that starts with a two channel signal and them extracts a right, left, center, and one surround channel, which was sent to two speakers. While SQ/QS might result in some "interesting" effects,I doubt it would work well for a reasonable cinematic experience.

That's my take in a nutshell. If you want the fine print, here ya go.

https://en.wikipedia.org/wiki/Dolby_Pro_Logic

 

[Kreshna]

I'm talking about multi channel movie soundtracks, either from the two RCA outputs on the cable box etc, or the RCA outputs on a DAC. If you have something else in mind please enlighten me.

That's matrixed multi-channel, where you "piggyback" surround channels into two-channel stereo. When you play it without decoder, ie, using stereo amplifier, then you'll hear normal stereo.

Dolby Stereo/Dolby Surround/Dolby Pro Logic is a matrixed tech that starts with a two channel signal and them extracts a right, left, center, and one surround channel, which was sent to two speakers. While SQ/QS might result in some "interesting" effects,I doubt it would work well for a reasonable cinematic experience.

That's my take in a nutshell. If you want the fine print, here ya go.

https://en.wikipedia.org/wiki/Dolby_Pro_Logic

So, anyone ever tried processing Dolby Pro Logic source using Sansui QS? What interesting effects did you hear? How good is Sansui QS in processing Dolby Pro Logic material?

 

[Grenadeslio]

That's matrixed multi-channel, where you "piggyback" surround channels into two-channel stereo. When you play it without decoder, ie, using stereo amplifier, then you'll hear normal stereo.


So, anyone ever tried processing Dolby Pro Logic source using Sansui QS? What interesting effects did you hear? How good is Sansui QS in processing Dolby Pro Logic material?

Explain how you intend to connect if not using the two RCA outputs.

Oh, and believe me, it's not stereo when connected as I described into a quad amplifier, it's definitely decoding the surround from the signal and making four discrete channels.

If you haven't tried it, go ahead and see for yourself.

 

[JoeESP9]

I for one am not surprised. They are both matrix based systems. However, I wouldn't call the output signals discrete, because they're not. IMO they should be called derived signals. To be discrete the original signal would have to consist of discrete channels. This is not the case with any two channel stereo signal. Any other channels derived from the original two channel signal can't be discrete as they are matrix based.