ALL TESTS ON THE SURROUND MASTER

[par4ken]

One of the virtues of QS was that the phase shifting was done after decoding just to put the channels back in phase. Decoding could even be done without the phase shifters as was done with the Photolume decoder.

With SQ very accurate phase shifts were needed to maximize separation.

Involve doing the phase shifting first loses that advantage, but if the SM filters are super accurate there should be no problem. It also makes SQ decoding possible without added circuity!

 

[chucky3042]

One of the virtues of QS was that the phase shifting was done after decoding just to put the channels back in phase. Decoding could even be done without the phase shifters as was done with the Photolume decoder.

With SQ very accurate phase shifts were needed to maximize separation.

Involve doing the phase shifting first loses that advantage, but if the SM filters are super accurate there should be no problem. It also makes SQ decoding possible without added circuity!

Mathematically on the decode it does not matter if it's done before or after

 

[Sonik Wiz]

@chucky3042 , besides being an audio genius, do you also have a few patents on various theft deterrence systems? Or is that some other Charles Van Dongen???

 

[chucky3042]

@chucky3042 , besides being an audio genius, do you also have a few patents on various theft deterrence systems? Or is that some other Charles Van Dongen???

Hey Sonik

You are stalking me!
Yep in fact that was a system called "keepit". It had a nasty history with a customer coming in with a need for a security system based on a wall wart that would create a security zone within a house, except he did not know how to do it. He granted us a wonderful 2% if we could work out how to do it, which became "sequrit" with a ton of patent work.

Along the way he became more and more dodgy and eventually we walked away. I had a think about it and worked out a way around our own created patent. It made the TV the home base station complete with around $5 of electronics (no wall wart), it could communicate over mains to all other electronic devices in the home with a similar electronic communications. In essence they set up a club such that if any member was missing (stolen) it would do a software lockout and not work - rendering it useless. Was a battle to get it all patented and eventually the patent examiner said it was one of the best patents he had dealt with.

Then it got nasty with the original guy - lets call him PSD who threatened us with all sorts of things, eventually one night I heard through one of my contacts (in tears and at 3 am at night) that he had put a hit man on me! Next morning I visited PSD and shall we say "discussed the matter" and he called off the hit man. I was very large and persuasive back then.

We eventually dropped it as consumer electronic product became so cheap, no one cared about theft anymore! Manufacturers were not interested in it as theft only created more sales.

Fun times

 

[gene_stl]

I think you are STILL large and persuasive , if a bit higher mileage.

 

[Sonik Wiz]

Hey Sonik

You are stalking me!

Nah, just stalking your patents. Ever since it was mentioned you do phase shifting before the decode & enhance I can't help but ask: why?

I think the Sansui approach to QS decoding is effective & elegant in its relative simplicity. It seems doing phase shifting, decoding, then directional enhancement would be much more involved. And then of course basic decoding accuracy would be dependent on the accuracy of the phase shifters (which you say are very good).

So I went back to studying what I have on your encode/decode schemes. Sure enough I see Lt/Rt early in the circuit both phase shifted & used straight. But all I can lay my hands on right now is a printed out US patent application. I have another one somewhere with newer info such as using the programmable DSP's but I can't find it (now where did I put that damn PDF file?).

So I checked out uspto.gov which has "updated" their website into a god awful mess. The only thing I find when I search is frustration. So off to google & that's when I ran across your other patents. Including the designs for electrostatic speakers. And I DL'ed a long time ago the patent info on your Y4 type speakers. Which I must say is a brilliant approach to a stable soundfield that no else has done before.

Any way why do you use phase shifting before all else? Does the newer DSP stuff require it? Or because it's easier to do accurate phased shifting on 2 chs than more at the decoded output?

 

[chucky3042]

Nah, just stalking your patents. Ever since it was mentioned you do phase shifting before the decode & enhance I can't help but ask: why?

I think the Sansui approach to QS decoding is effective & elegant in its relative simplicity. It seems doing phase shifting, decoding, then directional enhancement would be much more involved. And then of course basic decoding accuracy would be dependent on the accuracy of the phase shifters (which you say are very good).

So I went back to studying what I have on your encode/decode schemes. Sure enough I see Lt/Rt early in the circuit both phase shifted & used straight. But all I can lay my hands on right now is a printed out US patent application. I have another one somewhere with newer info such as using the programmable DSP's but I can't find it (now where did I put that damn PDF file?).

So I checked out uspto.gov which has "updated" their website into a god awful mess. The only thing I find when I search is frustration. So off to google & that's when I ran across your other patents. Including the designs for electrostatic speakers. And I DL'ed a long time ago the patent info on your Y4 type speakers. Which I must say is a brilliant approach to a stable soundfield that no else has done before.

Any way why do you use phase shifting before all else? Does the newer DSP stuff require it? Or because it's easier to do accurate phased shifting on 2 chs than more at the decoded output?

Hi Sonik

You are demonstrating what I really like about QQ in that its a highly intelligent/ educated/ hard nosed / one eyed audience and you actually pay attention to detail. The rest of the HIFi media really have no idea and just repeat the sales waffle from types like me.

You are probing way back into the bowels of my early concepts of Involve when I was examining all sorts of decode techniques including QS, SQ, Ambiosonics. As someone else observed SQ is a different and mind rapping beast but it does require the phase shifting to be done prior to the summations, see below:

this is because it sums combined in phase and 90 degree phase shift signals, eg the A' signal is Mix of L(-0.71 SHIFTED -90) + R(INVERTED X 0.71), just summing L + R in the right ratios and post phase shifting is not the same.


QS is different

As you can see all the summations are with the in shifted L/ R signals and we are NOT MIXING in phase and 90 degree shifted components. As such the phase shifts into L, L(-90), R, R(-90) can be done prior to the additions and produce the same answer.

Here is a snapshot of our 90 degree shift networks prior to the DSP:

Showing all 4 components going into the DSP.

The advantage of this was that I was making provision for future developments in case SQ were onto a good idea and it enabled me to frig with the maths of the shifted components if an idea hit me (it did not). As you know, I resisted incorporating SQ into the blue eyed monster (as I hate it) , but you guys can be very "persuasive". This meant it was a change that we could do without complicated hardware changes.

As you are stalking the patents, have you looked at my personal favorites "Sweet spot" and Intelligent encode? I have attached them below and I will ask questions later! Note the encoder had to be split into 2 patents as the passive version discovery of the wonders of the 0.21 ratio mix had to be covered

 

[kfbkfb]

SM (QS) and the Sansui implementations of QS VarioMatrix:

Kind of off the subject, but since Sansui provided the QS (encoder & VarioMatrix decoder) for both the 1974 BBC & 1975 NQRC tests and unfortunately QS didn't do well in either evaluation, I was wondering what could have gone wrong, obviously, the SM (QS) decoder works very well, but it's puzzling that Sansui couldn't make their VarioMatrix decoder work about as well as the SM.

Have there been psychoacoustics discoveries since 1973 (when the QS VarioMatrix system first appeared) that help make the SM superior to the Sansui VarioMatrix system or did the all analog composition of the Sansui VarioMatrix decoder somehow limit its directional enhancement?

edit: (BBC & NQRC info):
https://downloads.bbc.co.uk/rd/pubs/reports/1974-29.pdfhttps://worldradiohistory.com/Archive-All-Audio/Archive-Audio/70s/Audio-1978-05.pdf#page=28

Kirk Bayne

 

[chucky3042]

SM (QS) and the Sansui implementations of QS VarioMatrix:

Kind of off the subject, but since Sansui provided the QS (encoder & VarioMatrix decoder) for both the 1974 BBC & 1975 NQRC tests and unfortunately QS didn't do well in either evaluation, I was wondering what could have gone wrong, obviously, the SM (QS) decoder works very well, but it's puzzling that Sansui couldn't make their VarioMatrix decoder work about as well as the SM.

Have there been psychoacoustics discoveries since 1973 (when the QS VarioMatrix system first appeared) that help make the SM superior to the Sansui VarioMatrix system or did the all analog composition of the Sansui VarioMatrix decoder somehow limit its directional enhancement?

edit: (BBC & NQRC info):
https://downloads.bbc.co.uk/rd/pubs/reports/1974-29.pdfhttps://worldradiohistory.com/Archive-All-Audio/Archive-Audio/70s/Audio-1978-05.pdf#page=28

Kirk Bayne

Wow, thats a great post. I will have to crawl through them before I can comment! I just love some of the other articles and adds in the second one.

 

[chucky3042]

SM (QS) and the Sansui implementations of QS VarioMatrix:

Kind of off the subject, but since Sansui provided the QS (encoder & VarioMatrix decoder) for both the 1974 BBC & 1975 NQRC tests and unfortunately QS didn't do well in either evaluation, I was wondering what could have gone wrong, obviously, the SM (QS) decoder works very well, but it's puzzling that Sansui couldn't make their VarioMatrix decoder work about as well as the SM.

Have there been psychoacoustics discoveries since 1973 (when the QS VarioMatrix system first appeared) that help make the SM superior to the Sansui VarioMatrix system or did the all analog composition of the Sansui VarioMatrix decoder somehow limit its directional enhancement?

edit: (BBC & NQRC info):
https://downloads.bbc.co.uk/rd/pubs/reports/1974-29.pdfhttps://worldradiohistory.com/Archive-All-Audio/Archive-Audio/70s/Audio-1978-05.pdf#page=28

Kirk Bayne

I note a lot of the grizzles of the BBC tests were related to the image positional accuracy in all quad directions. This was sorta covered in little Max's early tests he did in the below document around page 8 looking at encode/ decode image position linearity. I think you would agree the result is rather good.

https://cdn2.imagearchive.com/quadraphonicquad/data/attach/74/74282-QS-tests.pdf

 

[Sonik Wiz]

Hi Sonik

You are demonstrating what I really like about QQ in that its a highly intelligent/ educated/ hard nosed / one eyed audience and you actually pay attention to detail. The rest of the HIFi media really have no idea and just repeat the sales waffle from types like me.

You are probing way back into the bowels of my early concepts of Involve when I was examining all sorts of decode techniques including QS, SQ, Ambiosonics. As someone else observed SQ is a different and mind rapping beast but it does require the phase shifting to be done prior to the summations, see below:
View attachment 85708
this is because it sums combined in phase and 90 degree phase shift signals, eg the A' signal is Mix of L(-0.71 SHIFTED -90) + R(INVERTED X 0.71), just summing L + R in the right ratios and post phase shifting is not the same.


QS is different
View attachment 85709
As you can see all the summations are with the in shifted L/ R signals and we are NOT MIXING in phase and 90 degree shifted components. As such the phase shifts into L, L(-90), R, R(-90) can be done prior to the additions and produce the same answer.

Here is a snapshot of our 90 degree shift networks prior to the DSP:

View attachment 85710

Showing all 4 components going into the DSP.

The advantage of this was that I was making provision for future developments in case SQ were onto a good idea and it enabled me to frig with the maths of the shifted components if an idea hit me (it did not). As you know, I resisted incorporating SQ into the blue eyed monster (as I hate it) , but you guys can be very "persuasive". This meant it was a change that we could do without complicated hardware changes.

As you are stalking the patents, have you looked at my personal favorites "Sweet spot" and Intelligent encode? I have attached them below and I will ask questions later! Note the encoder had to be split into 2 patents as the passive version discovery of the wonders of the 0.21 ratio mix had to be covered

Thanks for the reply!
Yes I already have those patents. What I don't have is a final patent on the decoder, just the patent app which I believe has errors. Not unusual in many patents but I don't have any correction supplement to know for sure.

For all the (deserved) popularity of the Surround Master decoder I think the real innovation is the smart encoder and Sweet Spot tech. Multi-band variable encoding is something not even possible back in the day. And I must say it's a lot of thought & 'tronics to produce a QS recording that is more stereo like. And the Sweet Spot is just gifted inspiration. I remember in olden days being told to strongly toe in the stereo speakers so if you move to the left, you'll be moving off axis to the left speaker & more on axis to the right speaker. I tried it. Didn't work very well. Even tho I haven't heard SST from what I read I can visualize it working very nicely.

I regards to the decoder patent again, would it be correct to characterize each decoded output has having 1 fixed & 2 variable coefficients? And I see just before output mixer there are multipliers. Is this a true multiplier where 2 input voltages equal a mathematically correct product? Or is it used in a more common sense as a Voltage Controlled Amp that variably mixes a signal into another one?

Gotta love that phase shift circuit. In ancient days it was always using a single transistor R/C combo & after each stage yet another crappy electrolytic to go to the base of the next stage. Using bipolar power supplies and top notch IC's makes a big improvement.

Haha Wendy Carlos diagrams! Her site & @MidiMagic are two of the most quad data intensive sites I know. Yeah, I think I could draw those SQ/QS circuits by memory but I might be a bit slow on the phasor diagrams.

 

[chucky3042]

Thanks for the reply!
Yes I already have those patents. What I don't have is a final patent on the decoder, just the patent app which I believe has errors. Not unusual in many patents but I don't have any correction supplement to know for sure.

For all the (deserved) popularity of the Surround Master decoder I think the real innovation is the smart encoder and Sweet Spot tech. Multi-band variable encoding is something not even possible back in the day. And I must say it's a lot of thought & 'tronics to produce a QS recording that is more stereo like. And the Sweet Spot is just gifted inspiration. I remember in olden days being told to strongly toe in the stereo speakers so if you move to the left, you'll be moving off axis to the left speaker & more on axis to the right speaker. I tried it. Didn't work very well. Even tho I haven't heard SST from what I read I can visualize it working very nicely.

I regards to the decoder patent again, would it be correct to characterize each decoded output has having 1 fixed & 2 variable coefficients? And I see just before output mixer there are multipliers. Is this a true multiplier where 2 input voltages equal a mathematically correct product? Or is it used in a more common sense as a Voltage Controlled Amp that variably mixes a signal into another one?

Gotta love that phase shift circuit. In ancient days it was always using a single transistor R/C combo & after each stage yet another crappy electrolytic to go to the base of the next stage. Using bipolar power supplies and top notch IC's makes a big improvement.

Haha Wendy Carlos diagrams! Her site & @MidiMagic are two of the most quad data intensive sites I know. Yeah, I think I could draw those SQ/QS circuits by memory but I might be a bit slow on the phasor diagrams.

Damn Sonik

You are are hard man to ********, you go for the details! I have always said my favorite patents are the encode and sweetspot (originally called Total Perspective.....I still prefer it). Involve decode was just 2 years of hard work and research but I always knew the direction to go. The real cleverish bit of the encode was the decision to not listen to the music like a machine and vary the variomatrix with adjusted control parameters heavily weighted in accordance to human hearing and perception. My experience with the original analogue implementation was that tollerance was the real deal breaker and going to digital software was the way forward. It took 4 months of educating Dave the ***** into the wicked ways of Involve before he even started trialing software - a process that took an additional 2 years to get sounding right. Despite appearances Dave is one of the smartest and most creative engineers I have known and it really pushed him (Lets not talk about the horrors of SQ).

The decoded outputs use 3 variable coefficients controled by a software VCA emulator.


I have attached the latest and greatest Involve Encode patent.

Smart encode was a frustration for several years as I really did not have a good solution to the basic QS encode matrix equations. The problem was always the stereo encode sucked and sounded left/ right image compressed compared to stereo of SQ. Then one day I decided to investigate just what is the minimum separation Joe average could perceive and I set about to build a cross talk jig to do just that. I thought the magic number would be around the good ol 20 dB but to my surprise, none of my test apes could pick better than 12 dB!! Wow I thought, so I then played with the ratios of the Involve encode basic matrix and adjusted the cross feed parameter to 0.21 instead of the 0.41, this yielded a worst case surround decode separation of 12 dB in certain directions. Sure enough - no one could pick the difference and the encode also had 12 dB separation. I KNOW THIS IS CONTROVERSIAL! This actually became the first encode patent.

The thought then hit me that music sometimes has lots of surround - and other times its just plain vanilla stereo. Why not crank up the surround parameters when there is lots of surround and reduce it when its stereo. That way we have a dynamic variomatrix encoder. It turned out that on listening tests (we really do a lot of that) that we found it sounded better with a minimum crossfeed parameter of 0.25 was better, so it actually wiggles dynamically between 0.41 to 0.25 (not mentioned in the patent). Given this is also happening in Tri band some constants a re gunna be high and some low- gets all a bit confusing for a guy with minimal brain processing power like me. I like to think we are really good at masking attack/ decays per band so no one can perceive things. remember one of the virtues of the Sansui variomatrix is that at all times it is balanced to minimize any possibility of pumping and surging. On all our test no one can pick the difference between stereo and Involve stereo encode. The recent Suzanne Ciani quad release vinyl was encoded in Intelligent 3 band variomatrix involve!

The SST sweet spot was the really hard nut to crack and I was literally thinking for 2 years with no end solution, nothing panned out. Then on a Saturday racer pedal bike ride between a bike crash and a phone call from a stupid lawyer, the idea hit me out of the blue, and it was so simple. You can mock it up mechanically at home with 4 conventional speakers (we used electrostatics as the SPL drops less with distance), just position the immediate speakers forwards and the delayed speakers behind- that's what Dave and I did and BING IT WORKED! Suddenly the central vocalist stayed in the center regardless of where we sat in the room. Next it was relatively easy to do the delays electronically as is done in the Y4. The bigger the speakers the better the effect is. Our Chris did a demo to a bunch of product designers a few days ago (Cobalt design) and they all "got it" and found they could sit anywhere and just walked into a sound scape (I love hard audiences)

Yep I just love Wendy's and Midi magics sites!

 

[chucky3042]

Damn Sonik

You are are hard man to ********, you go for the details! I have always said my favorite patents are the encode and sweetspot (originally called Total Perspective.....I still prefer it). Involve decode was just 2 years of hard work and research but I always knew the direction to go. The real cleverish bit of the encode was the decision to not listen to the music like a machine and vary the variomatrix with adjusted control parameters heavily weighted in accordance to human hearing and perception. My experience with the original analogue implementation was that tollerance was the real deal breaker and going to digital software was the way forward. It took 4 months of educating Dave the ***** into the wicked ways of Involve before he even started trialing software - a process that took an additional 2 years to get sounding right. Despite appearances Dave is one of the smartest and most creative engineers I have known and it really pushed him (Lets not talk about the horrors of SQ).

The decoded outputs use 3 variable coefficients controled by a software VCA emulator.


I have attached the latest and greatest Involve Encode patent.

Smart encode was a frustration for several years as I really did not have a good solution to the basic QS encode matrix equations. The problem was always the stereo encode sucked and sounded left/ right image compressed compared to stereo of SQ. Then one day I decided to investigate just what is the minimum separation Joe average could perceive and I set about to build a cross talk jig to do just that. I thought the magic number would be around the good ol 20 dB but to my surprise, none of my test apes could pick better than 12 dB!! Wow I thought, so I then played with the ratios of the Involve encode basic matrix and adjusted the cross feed parameter to 0.21 instead of the 0.41, this yielded a worst case surround decode separation of 12 dB in certain directions. Sure enough - no one could pick the difference and the encode also had 12 dB separation. I KNOW THIS IS CONTROVERSIAL! This actually became the first encode patent.

The thought then hit me that music sometimes has lots of surround - and other times its just plain vanilla stereo. Why not crank up the surround parameters when there is lots of surround and reduce it when its stereo. That way we have a dynamic variomatrix encoder. It turned out that on listening tests (we really do a lot of that) that we found it sounded better with a minimum crossfeed parameter of 0.25 was better, so it actually wiggles dynamically between 0.41 to 0.25 (not mentioned in the patent). Given this is also happening in Tri band some constants a re gunna be high and some low- gets all a bit confusing for a guy with minimal brain processing power like me. I like to think we are really good at masking attack/ decays per band so no one can perceive things. remember one of the virtues of the Sansui variomatrix is that at all times it is balanced to minimize any possibility of pumping and surging. On all our test no one can pick the difference between stereo and Involve stereo encode. The recent Suzanne Ciani quad release vinyl was encoded in Intelligent 3 band variomatrix involve!

The SST sweet spot was the really hard nut to crack and I was literally thinking for 2 years with no end solution, nothing panned out. Then on a Saturday racer pedal bike ride between a bike crash and a phone call from a stupid lawyer, the idea hit me out of the blue, and it was so simple. You can mock it up mechanically at home with 4 conventional speakers (we used electrostatics as the SPL drops less with distance), just position the immediate speakers forwards and the delayed speakers behind- that's what Dave and I did and BING IT WORKED! Suddenly the central vocalist stayed in the center regardless of where we sat in the room. Next it was relatively easy to do the delays electronically as is done in the Y4. The bigger the speakers the better the effect is. Our Chris did a demo to a bunch of product designers a few days ago (Cobalt design) and they all "got it" and found they could sit anywhere and just walked into a sound scape (I love hard audiences)

Yep I just love Wendy's and Midi magics sites!

Hey Sonik
One of our USA contacts RICO that consults to MIT sent me this interview at the NAMM exhibition a few years ago we did in USA, It covers some of the topics discussed by us. Enjoy.....Dave is the eye candy

 

[M-D-Z]

https://immersiveaudioalbum.com/inv...-pioneers-revisit-improve-quadraphonic-sound/
The introduction bulb says it’s a “mid-fi” device, but I’m not sure this is a fair assessment, read on about the setup he used to listen and review, certainly not a high-fi rig - so this review is flawed in my view.

 

[mandrix]

Reads like a pretty fair review to me, with the caveat I do not own the device myself.

 

[ar surround]

https://immersiveaudioalbum.com/inv...-pioneers-revisit-improve-quadraphonic-sound/
The introduction bulb says it’s a “mid-fi” device, but I’m not sure this is a fair assessment, read on about the setup he used to listen and review, certainly not a high-fi rig - so this review is flawed in my view.

I think it is an accurate review of the device. I didn't realize that it was written by our own sjcorn until I got to the end. Two interesting observations in the article:

1) Alan Parsons I Robot:

"...the Surround Master V3’s 4.0 presentation sounded almost like a real matrix quadraphonic LP!"

That's what I've noticed about Parson's work...that the stereo versions are magnificent when played through the Surround Master.

2) Regarding the SQ of Happy Man:

"The decoder does an effective job of largely isolating the acoustic guitar in the right rear speaker after the false start, but the soundstage becomes less precise as the other three channels enter the picture. The rhythm section is clearly arrayed across the front channels only on the Blu-Ray disc, while it sounds like it’s coming from all around on the vinyl quad presentation. I also noticed that the lead vocal seemed to extend further into the room on the vinyl, whereas it stayed pinned to the front speakers only on the Blu-Ray."

It seems to me that the SQ LP version played through the SM, while not as discrete, might actually be the more satisfying presentation of the song. I like rhythm all around and vocals extending into the room.

 

[M-D-Z]

I think it is an accurate review of the device. I didn't realize that it was written by our own sjcorn until I got to the end. Two interesting observations in the article:

1) Alan Parsons I Robot:

"...the Surround Master V3’s 4.0 presentation sounded almost like a real matrix quadraphonic LP!"

That's what I've noticed about Parson's work...that the stereo versions are magnificent when played through the Surround Master.

2) Regarding the SQ of Happy Man:

"The decoder does an effective job of largely isolating the acoustic guitar in the right rear speaker after the false start, but the soundstage becomes less precise as the other three channels enter the picture. The rhythm section is clearly arrayed across the front channels only on the Blu-Ray disc, while it sounds like it’s coming from all around on the vinyl quad presentation. I also noticed that the lead vocal seemed to extend further into the room on the vinyl, whereas it stayed pinned to the front speakers only on the Blu-Ray."

It seems to me that the SQ LP version played through the SM, while not as discrete, might actually be the more satisfying presentation of the song. I like rhythm all around and vocals extending into the room.

Well yes, I did like, and agree with the positive review, I should have been more clear about what I meant by flawed. The intro blurb says “Mid-Fi”. I trust that in a higher-fidelity system beyond what was used in the test setup, the SM V3 would not degrade such a system by being a Mid-Fi device.

Do those who own and use the current SM integrated into a very good system consider it to be a “Mid-Fi” component? Just wondering what you guys who have them actually think. I ask because I do not yet own one, been waiting to see it arrive in a full-featured Involve designed and built preamp.

 

[chucky3042]

Well yes, I did like, and agree with the positive review, I should have been more clear about what I meant by flawed. The intro blurb says “Mid-Fi”. I trust that in a higher-fidelity system beyond what was used in the test setup, the SM V3 would not degrade such a system by being a Mid-Fi device.

Do those who own and use the current SM integrated into a very good system consider it to be a “Mid-Fi” component? Just wondering what you guys who have them actually think. I ask because I do not yet own one, been waiting to see it arrive in a full-featured Involve designed and built preamp.

Yep, I liked the review but I dunno where the "mid fi" comment came from as by any tests it really is tip top fi. I suppose if the price tag is around 1 k it is deemed to be mid fi.

 

[marpow]

I can't believe I never looked into this as a long time QQ member. I am getting overly excited.
Please let my brain process this my way.
1. I have dedicated PC with JRiver for playback of all stereo or MCH.
2. USB out to dedicated Exasound MCH DAC, 6 RCA's out from the DAC to the 7.1 space in back of my Pre/Pro.
3. Questions:
Can I purchase surround master and without rearranging the Exasound DAC, go optical out from the PC to the surround master?
Or
Can the surround master take the place of the Exasound, which is fantastic, by the way.
Looking at rear of Surround Master I see I can deliver optical in, but looks like I have to go RCA out, therefore taking the space that the Exasound already has.
Attached PDF Page 10 shows back of my unit if any one was able to give me input, sounds like a great piece of gear that I would enjoy.

 

[gene_stl]

The actual answer is probably that it doesn't much matter. All the equipment you mentioned is late model and good quality so however you hook it up it's gonna sound great. The surround master has a DSP unit in it that is very good and the Exasound is about as good as it gets. Your pdf is of a McIntosh and I don't think there would be any complaints about the sound of that either.

You are running up against one of the big problems with multichannelism. The lack of versatile preamp/processors with flexible and sufficient input switching quantity. The MX122 at least has one single RCA mch input.

What you could do is get two of these:
https://www.amazon.com/CIMPLE-CO-Selector-Composite-Switcher/dp/B07C15XGQN/ref=sr_1_20?crid=DYX30F7VIUXB&keywords=switch+box+video&qid=1672708639&s=electronics&sprefix=switch+box+video,electronics,136&sr=1-20&th=1

and put them between the Exa and the SM on the inputs and the MX 122 on the output. You will have to push two buttons to switch between them.
I have one of these and there is no difference at all between the audio and video channels except the color of the RCA receptacles. This is not elegant but will allow you to have the best of both worlds without having to rassle with cables. There are also some solutions from folks like Zektor and others that will work maybe even better but this would cost $40 to try out.

http://www.laaudiofile.com/mas71.html
http://www.colemanaudio.com/swtchr.htm
https://hometheaterhifi.com/reviews/audio-accessory/switchers/a-secrets-switcher-accessory-review/