Penteo "Panorama Slicing" vs. Sansui VarioMatrix in "Sythesizer" mode

[jsrstereo]

Here's probably a dumb question from a certified non-technoid:

Just how does Penteo's panorama slicing differ from Sansui's Synthsizer mode?

Thanks, John R

 

[zeerround]

I'm sure there are many here that can speak with authority about the Sansui but google/Wikipedia says it's a form of matrix decoder, so is looking for phase differences in left and right.

Panorama slicing would describe splitting the stereo mix into zones or slices, and routing those to the different 5.0 channels.

SpecWeb and Penteo could both be described that way. SpecWeb is (mostly) based on the magnitude (vs. phase) in the left and right channels (for SpecWeb, in the frequency domain). I don't claim to understand the math in Penteo, but I believe it is based on both magnitude and phase (also in the frequency domain).

Matrix decoding is going to depend on the stereo being intentionally matrix encoded, else all you get is sort of ambient sounds, that are out of phase with the dominant instruments being put in the rears.

SpecWeb and Penteo work from stereo panning, which is a part of every (modern) stereo recording (vs. early stereo where things were only in one channel or the other - see early Beatles etc.)

Also they make separate channel assignments on a frequency basis, vs. in the time domain like a matric decoder. Imaging a graphic equalizer with 8192 faders. At any given moment an independent channel assignment is made based on a L R comparison for each of those 8192 channels.

Does that help?

 

[jsrstereo]

I'm sure there are many here that can speak with authority about the Sansui but google/Wikipedia says it's a form of matrix decoder, so is looking for phase differences in left and right.

Panorama slicing would describe splitting the stereo mix into zones or slices, and routing those to the different 5.0 channels.

SpecWeb and Penteo could both be described that way. SpecWeb is (mostly) based on the magnitude (vs. phase) in the left and right channels (for SpecWeb, in the frequency domain). I don't claim to understand the math in Penteo, but I believe it is based on both magnitude and phase (also in the frequency domain).

Matrix decoding is going to depend on the stereo being intentionally matrix encoded, else all you get is sort of ambient sounds, that are out of phase with the dominant instruments being put in the rears.

SpecWeb and Penteo work from stereo panning, which is a part of every (modern) stereo recording (vs. early stereo where things were only in one channel or the other - see early Beatles etc.)

Also they make separate channel assignments on a frequency basis, vs. in the time domain like a matric decoder. Imaging a graphic equalizer with 8192 faders. At any given moment an independent channel assignment is made based on a L R comparison for each of those 8192 channels.

Does that help?

Greetings Zeerround and thanks for your reply. The reason for my question is that I understand (?) that Sansui's VM Synthesizer mode is different from its QS and Hall modes (matrix based) in that it places the extreme left-hand portion of the stereo signal in the left-rear channel, while steering the remaining portion to the left-front channel, with same effect for the right-hand signal. This seems to me to be a kind of "panorama slicing" - so I wonder if that is similar (or not) to Penteo's Panorama Slicing?

So is Sansui's Synthesizer really a kind of "panorama slicer"?

Thanks, John R

 

[zeerround]

https://manualzz.com/doc/6337128/sansui-qs-tech-manual
So "I guess" yeah, a panorama slicer. "directionality of the loudest sound via phase discrimination" (i.e. analog time domain). This model did that for three separate frequency bands.

SpecWeb, typically, uses 8192 bands. I imagine Penteo uses at least 1024. It's been a while since I looked at any published details.

 

[zeerround]

Just for grins I went into my Plogue Bidule archive to see if I had any layouts simulating this. I see lots of QS and SQ decoders, and a Shadow Vector decoder (along with the patent), but didn't find (by guessing partial file names) a Vario Matrix layout.

(Most of) these were not made by me, and you may have seen them in various early Plogue Bidule stereo to 5.1 layouts.

 

[par4ken]

Greetings Zeerround and thanks for your reply. The reason for my question is that I understand (?) that Sansui's VM Synthesizer mode is different from its QS and Hall modes (matrix based) in that it places the extreme left-hand portion of the stereo signal in the left-rear channel, while steering the remaining portion to the left-front channel, with same effect for the right-hand signal. This seems to me to be a kind of "panorama slicing" - so I wonder if that is similar (or not) to Penteo's Panorama Slicing?

So is Sansui's Synthesizer really a kind of "panorama slicer"?

Thanks, John R

Yes it does exactly that. Sounds panned left to right are expanded (or magnified in my books) to decode from left back through the fronts and around to right back. Any out of phase or deliberately encoded rear signals (if present) will still decode across the rear. No slicing if that's what "panorama slicing" does, it's a completely linear panning function.

 

[zeerround]

SpecWeb has a panning mode. That's how it was originally designed, but it also has "slice" modes, and over time people have preferred that, so the steering logic is now (what we are calling here, I call it zone, because "slice" is used for a different angle detection process) slice by default. Options for constant power panning, constant amplitude panning, and ambinsonic panning (ambisonic and least in the Plogue version) are selectable.

By the way I found this thread here on QQ: A Vario-Matrix Survival Guide