New Vinyl Based Surround/Quad System (Hypothetical Question)

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Q8

1K Club - QQ Shooting Star
Joined
Aug 30, 2012
Messages
1,751
Location
Ohio
Heya,

I have an interesting hypothetical question, especially aimed at the technical members of the board.

In your oppinion, if one was to embark on creating a new vinyl record based quad or surround format. How would you go about it? Would you use a matrixed system or a discrete system? How would it work? Would it be legacy compatable with Stereo and or other Quad formats? What speed would the records rotate? Would the records be compatable with legacy stereo or quad equipment?

Some guidlines/things to remember:

-It must be vinyl record based.
-The audio itself cannot be digitally processed
-It has to involve a new type of vinyl record. This is not about improving playback of existing formats.
-The only other guidline is that there are no other guidlines.
 
I would adopt the dbx II system for all new vinyl records, and make them CD-4. Matrix would work too. I would jump it to 45rpm but then youre going to be flipping record sides a lot more. Its a question of quality vs user friendliness.
 
I would adopt the dbx II system for all new vinyl records, and make them CD-4. Matrix would work too. I would jump it to 45rpm but then youre going to be flipping record sides a lot more. Its a question of quality vs user friendliness.

+1
 
I really like the DBX II NR system for LPs, and I have a number of DBX-encoded albums (some QS encoded also). The one drawback (and it may or may not be an issue, depending on how pristine you keep your vinyl or how good the pressing is in the first place) is that it is a 2 to 1 encode/compression then 1 to 2 decode/expansion system.

Levels below a predetermined threshold (including hiss, rumble and normal record noise) are halved in volume, rendering most of it inaudible. Levels above that threshold are doubled in volume, resulting in dynamic range that can reach 100 dB. It is almost uncanny how you can forget that you are listening to a vinyl LP.

The problem though, is that any clicks or pops ABOVE that threshold are also doubled in volume. Unless the vinyl is very clean and damage-free, the results can be unpleasant to listen to ... and speaker damage could also result.
 
Hi All

Personally I would use Hi Com noise reduction as it does not suffer from the pumping issues found on DBX (Yes I am a cassette nutter) and off course I would use our INVOLVE encode/ decode system (I am biased - see https://www.quadraphonicquad.com/fo...-Reality-Technologies-New-surround-technology).

Regards

Charlie

I really like the DBX II NR system for LPs, and I have a number of DBX-encoded albums (some QS encoded also). The one drawback (and it may or may not be an issue, depending on how pristine you keep your vinyl or how good the pressing is in the first place) is that it is a 2 to 1 encode/compression then 1 to 2 decode/expansion system.

Levels below a predetermined threshold (including hiss, rumble and normal record noise) are halved in volume, rendering most of it inaudible. Levels above that threshold are doubled in volume, resulting in dynamic range that can reach 100 dB. It is almost uncanny how you can forget that you are listening to a vinyl LP.

The problem though, is that any clicks or pops ABOVE that threshold are also doubled in volume. Unless the vinyl is very clean and damage-free, the results can be unpleasant to listen to ... and speaker damage could also result.
 
Hi Again

Thinking out loud, any compander system would make the record a non universal system, so any pre compression would need to be very subtle but preferably non at all.
 
I would use CD-4 as a reference, except I would use the
CBS CX analog noise reduction system
(which was developed for vinyl records) on the sum signals
(LF+LB in L and RF+RB in R, both with a maximum
bandwidth of 20kHz) and a single FM carrier (starting at
25kHz) that contains both LF-LB and RF-RB (the phono
cartridge would only need wide frequency response,
not channel separation above 20kHz).

I would also use a powerful analog noise reduction system
on the LF-LB and RF-RB signals (as suggested in previous
posts).

The resulting vinyl record would be compatible with existing
stereo (and mono) record players and would provide low
noise (all analog!) discrete quadraphonic sound with a suitable
phono cartridge and descrambler/demodulator/decoder.

Kirk Bayne
 
That sounds great Kirk. What equipment currently utilzes CBS CX analog noise reduction system?
 
That sounds great Kirk. What equipment currently utilzes CBS CX analog noise reduction system?

Columbia CX lp's got the worst ever audiophile reviews from Absolute sound magazine over 30 years ago... they provided us with a complete list of lp's in order to be avoided at all costs.
 
Personally if I decided to re-introduce a new four channel vinyl format I'd keep it simple with an updated CD-4 (..isn't CD-4 out of patent by now..??) and just include a variation of the QS Synth for non-encoded stuff. You could design it to auto-detect the CD-4 carrier and default to the QS Synth for every other (Stereo) source...then you could have Quad everything...
 
I personally would lean towards no noise reduction whatsoever. It just creates another step the audio has to go through. Also it seems that there are always situations where it makes something you want quieter, louder and something you want louder, quieter. I like to hear a recorded source as purely as possible. Thats why most of us get into vinyl in the first place.

Lots of interesting ideas so far though!
 
Agreed

I personally would lean towards no noise reduction whatsoever. It just creates another step the audio has to go through. Also it seems that there are always situations where it makes something you want quieter, louder and something you want louder, quieter. I like to hear a recorded source as purely as possible. Thats why most of us get into vinyl in the first place.

Lots of interesting ideas so far though!
 
The only improvement I would make in the CD-4 system
would be to replace the preemphasis and ANRS parts of
the FM carriers with a more powerful analog noise reduction
system (perhaps the one used for VHS HiFi).

(When listening with headphones, I can hear the noise level
increase when the carriers are switched on, a more powerful
noise reduction system would eliminate the noise increase.)

Kirk Bayne
 
Hmm, it definately seems like more people lean towards a CD-4 based system thus far.

I can see the advantages of that, but in modern times, I would imagine it's pretty easy to make a matrixed system that works very well.

One thing I wonder, is could more channels be squeezed on a stereo groove with a matrixed system. With today's technology could we decode 5.1 off of a stereo vinyl record (without using digital technology, and with a record still compatble with stereo/mono systems)?

Just another random thought.
 
My preference would be QS on high-quality vinyl. It is the most "discrete" matrix system (even though I have a Tate), and it plays better in stereo than SQ. CD-4 has better separation, but it is fussy. Modern tonearms and many cartridges will play them properly, and modern interconnects are usually low capacitance ... but pressings are usually noisier and more delicate. Recording length is limited, because the inner grooves are less than optimal for CD-4 use. For any "universal" LP system to succeed, it must be acceptable to the audiophile sector who only listens in stereo. This is another reason to rule out compander noise reduction ... less is more.

As for 5.1 ... a centre channel can be easily decoded from the mono signal in the front channels, and the "point 1" subwoofer channel is only really useable for movie effects. I can't see it being missed in music playback ... especially given the technical challenges of playing back deep bass on a vinyl system ... acoustic feedback is not your friend.
 
It would be nice to use a center for lead vocals. As far as using a sub, it may be useful in getting more Dance/R&B/Hip-hop artists into multi-channel recording. As far as acoustic feedback goes. I have created some pretty insane bass from vinyl sources without having (much) trouble with feedback.

But really the two extra speakers are not necissary and possibly not practical. I just wanted to see what people have to say about trying to encode more channels on a stereo vinyl record.
 
Hmm, it definately seems like more people lean towards a CD-4 based system thus far.

Just being practical.. :) ..The advantage of CD-4 is that all the tech-work has been done you could implement it immediately (with a few high tech upgrades)...and the combo I suggested with an updated QS Synth (..or chuckys 3042's "Involve" decoder)...ditto, (..just about) all ready to go. With those two, you've got all your bases covered for high quality Quad vinyl replay/decoding. This combo I think would be fairly label friendly as well...those that wish to go the whole hog and remix in discrete Quad can do so, those that can't afford to do so can still tailor the stereo mix to maximise the quad effect with little effort...(although there's always the possibility of the "mono reprocessed for stereo" mixing disaster's of the early stereo era)..

If you had the cash...and could interest some major labels to remix some popular legacy (..or new) music to Quad it could all happen fairly quickly. With the current resurgence in vinyl....now'd be just about the perfect time to try this.
 
This combo I think would be fairly label friendly as well...

I'm not sure how the labels would react to CD-4 technology being used again. From a profits standpoint, it would be much cheaper to crank out matrixed albums. No special equipment and less skilled employees needed to cut the masters. They can use the stampers longer. They can use cheap vinyl. They don't have to have as good of quality control. From the consumer standpoint it would be a great product, but I don't know how quick the record industry would warm up to the idea of dusting off CD-4 technology again.
 
Let's not discount that record labels will NEVER do things in a logical and straightforward way. History has shown that whenever there is an opportunity for an old-fashioned format war ... and keep in mind that it pretty much started with quad ... that they will get dirty and nasty and kill it all. Before the VHS - Beta, the SACD - DVD-Audio, and the HD DVD - Blu-ray battles, equipment manufacturers and record labels have proven that they just never learn ... and that they never listen to consumers.
 
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