Best source material for fake quad? Does it matter?

[gvl_guy]

I know that many stereo recordings can sound pretty fantastic synthesized into quad. I know it's all about the decoder, whatever type it might be, finding out of phase material.

But does it matter what that source is for the music to have stuff that's out of phase? Will a stereo CD played through, for example, the Surround Master sound about the same as if the vinyl version is played? (I'm not talking about anything other than the quad effect.) Same with streaming something stereo vs. playing a recorded file? Will the quad effects be the same or does the medium for playback affect phasing?

Thanks for your help.

 

[kfbkfb]

https://www.radio4all.org/stereo-vs-joint-stereo/
Streaming (or any audio data reduction system - satellite radio, HD radio, DAB radio) may use joint stereo instead of stereo, which could adversely affect synthesized surround sound.

FM (or stereo AM) audio processing (sometimes distorts the phase between L and R) could also adversely affect synthesized surround sound.

Stereo compact cassette, Vinyl, CD, DVD, Blu-ray sources should sound nearly the same in synthesized surround sound.


Kirk Bayne

 

[furui_suterioo]

I know that many stereo recordings can sound pretty fantastic synthesized into quad. I know it's all about the decoder,

I would say it's all about the source rather than the decoder. If you have a good source it will generally sound good any decent decoder.
The S&IC Tate is extremely sensitive to low sound quality often found on YT whereas the Sansui and Involve not quite as sensitive. I have a list of LPs I want to physically buy because the digital versions are don't sound right. It really depends on whether or not the cd/digital version has been mastered better than the original Lp. I usually try out multiple sources of an album on multiple decoders before recording onto tape.

 

[Scott65]

I've had great results with the Surround Master using various sources - CD, FM radio, Internet radio, DAB+. The results in my experience depend on the characteristics of the individual song being played and not the source.

 

[Electric Moo]

+1 on the Surround Master

I've had the same experience playing non-quad encoded stereo material as mentioned above. I've ripped a few LP's just to save wear & tear on them, and I can repeat play albums easier that way. If I have time, it's nice to throw an LP on & bask in the sound from the source though. CD's have been fine too.

 

[par4ken]

I've decoded stereo forever. As furui_suterioo says anomalies show up more on the S&IC than the Sansui (QSD-1). It goes without saying that the better the quality of the signal the better the results. Still I get acceptable results from almost any source, with either decoder.

I have often described the way these super decoders enhance stereo is like "listening through a magnifying glass". The stereo is expanded (pulled apart) across the four speakers, intricacies of the mix are much easier to hear than with plain old stereo.

Sansui used the term "Synthesizer" right from the beginning. That might have been a good descriptive term in the beginning when they were using "phase modulation" to simulate the sound field. It is a term that does the operation of their Vario-matrix decoder a disservice! Nothing is synthesized!

 

[furui_suterioo]

I will add that I haven't really made a thorough comparison of stereo upmixing between Involve and Sansui because I don't have a proper stereo widener to use with the Involve.
I did try a smartphone app widener with the Involve and it was working but was downsampled to 16 bit. Using the Involve with a quality stereo widener might be better than a Sansui in synth since it would be fully adjustable.

 

[MidiMagic]

The mastering software I use contains a wider/narrower and has an oscilloscope display so I can see the results.

.My Phlazex project can be used as a widener/narrower. It is a passive analog device.

 

[barfle]

IIRC, I have a handful of stereo recordings of “wind in the trees” type of sounds, ans with all the basically pink noise in both channels, lots of sound comes from the back when played through SQ decoders. Lots of fun!

 

[Wunlow]

Listing the decoding method helps as it will somewhat determine what goes where.

QS ..*if* I recall correctly (as I no longer have that decoder) tended to do a mild horseshoe type of decoding on hard left or right panned material, while SQ and DPL-1 / DPL-2 keep hard left and right in their correct positions if all goes correctly, and relies much more on phase relationship.

I prefer the SQ and DPL2 formula extractions for fake surround as the material meant to stay in the front does ("meant" being a vague term in this given case when upmixing material that was never intended to be decoded this way) while out of phase information provides surprise material can occasionally pop up in the rears. If one always wants their rear speakers always active then this approach could be disappointing to some. So to each to their own I suppose. If you do like the SQ/DPL approach to upmixing, the DTS Nureal unofficially adheres to the DPL-2 decoding and is multi-band in nature (both good and bad for different reasons) but as it is multi-band it tends to handle material never intended for upmixing quite well.

My 2 cents, and again - everyone's own preferences will vary.