CD-4 vs. Discrete Reel

[JonUrban]

Here's a question for all of you, especially the old timers like Jonathan or Aldo, or even new timers like fredblue!

When you have a Q4 reel with a song that has dead silence in the rears for a minute or more, before something appears in the rears, is it actually possible to get that playback from a CD-4 LP with the very best demodulator and cartridge? I am wondering if there were in fact different mixes made for CD-4 LP encoding that did not leave channels totally empty.

We know that a song like "Night Game" from Paul Simon's "Still Crazy After All These Years" has a different mix on the Q8 than it does on the SQ as SQ probably had an issue with empty channels as well. But what about CD-4 stuff.

So has anyone ever tested this out. I know there are channel identification 45s that came with demodulators, but right now I do not have a CD-4 setup to try anything and there is a test I wanted to try but I can't.

Anyone have any info?

 

[winopener]

Too few conversion from CD4 done by me to have this experience, but i think i can identify some possible sources for test:
America, both Holiday and Hearts have long intro without anything on the rears
Deodato, japanese Prelude, on the 2001 track the right left is very silent for a while

Other sources?

 

[JonUrban]

Yes, the America's are good, as is James Taylor's "Wandering" from "Gorilla".

 

[fredblue]

Here's a question for all of you, especially the old timers like Jonathan or Aldo, or even new timers like fredblue!

When you have a Q4 reel with a song that has dead silence in the rears for a minute or more, before something appears in the rears, is it actually possible to get that playback from a CD-4 LP with the very best demodulator and cartridge? I am wondering if there were in fact different mixes made for CD-4 LP encoding that did not leave channels totally empty.

We know that a song like "Night Game" from Paul Simon's "Still Crazy After All These Years" has a different mix on the Q8 than it does on the SQ as SQ probably had an issue with empty channels as well. But what about CD-4 stuff.

So has anyone ever tested this out. I know there are channel identification 45s that came with demodulators, but right now I do not have a CD-4 setup to try anything and there is a test I wanted to try but I can't.

Anyone have any info?

hi Jon,
i don't have any discrete point of reference for JT's Gorilla Quad (don't own the Q8 and never found a Q4 conversion) so i don't know if there should be any lead vocals in the Rears on "Wandering"?

anyway i recorded in the track demodulated with two different units, they sound pretty different to me; first through a JVC 4DD-5 and redid it thru the Grundig Quadro this morning (both on the SL1210 with an AT440MLb). neither wipes out the lead vocal in the Rear channels and there's some distortion but both do some nice things with those gorgeous harmony vocals and the sensation of surround seemed effective to me in both cases. i can post up links to clips here or start a conversation as you prefer if you'd like to hear the results to compare to your Q4?

oh also after reading winopener's comments, i did a track from America's "Holiday" ("Glad To See You") through both JVC 4DD-5 and the Grundig Quadro. again some interesting differences, not just in terms of exactly what's getting separated (the piano intro is mostly upfront in both cases but the amount of Rear channel reverbs different between the two demodulators; have both demods setup to squeeze as much separation as poss) and to hear how much of each element is getting through to each channel but also in the sound and texture/ timbre etc of the two demodulators. cool little experiment! what was the test you wanted to try?

 

[sjcorne]

When you have a Q4 reel with a song that has dead silence in the rears for a minute or more, before something appears in the rears, is it actually possible to get that playback from a CD-4 LP with the very best demodulator and cartridge?

I'm no expert, but I think even if you fine tune the separation and carrier knobs on your demodulator to absolute perfection, you'll always get some kind of suppression artifact in the rears because of the way the system works. Though when you're playing all four channels simultaneously, it should create the illusion of silence coming from the rears.

Interestingly enough, dead silence in the rears actually seems to be more common on SQ records in my experience (Billy Joel's "Billy The Kid", Aerosmith's "Big Ten Inch Record", etc).

We know that a song like "Night Game" from Paul Simon's "Still Crazy After All These Years" has a different mix on the Q8 than it does on the SQ as SQ probably had an issue with empty channels as well.

I always thought it was the same mix, but it doesn't sound good decoded because of the dead channel. I actually just picked the Still Crazy Q8, so I'll compare with the LP through the Tate. Not sure I've ever heard a Columbia Q8 with a different mix than it's SQ counterpart, but whoever mixed that one was certainly not thinking about SQ compatibility.

Deodato, japanese Prelude, on the 2001 track the right left is very silent for a while

Was Prelude ever released in CD-4? I've only seen Deodato 2 (King 4D-6).

 

[winopener]

My mistake on messing up the Deodato releases.
On comparing cd4 vs qr or sacd (America Hearts does exist on all three) we do need to keep in mind about channel separation that the 45-45 Westrex system, which is the base of stereo records, has a L-R channel separation between 35-40 dB, so the leakage is inherent on any stereo or quad record by this very basic fact. Sure cd4 is discrete, but... as discrete as a record can be, which is not on the same league as a discrete tape or a digital media.

 

[quadtrade]

Yes, the America's are good, as is James Taylor's "Wandering" from "Gorilla".

Wandering is blank for about 30 seconds at the start of the reel. Very Minimal sound for 20 seconds. Blank again for a while. According to visual look at the file.

 

[Philip Spinner]

The first track on side 2 of the J Geils Band is mono on one track, I think front left but not sure, for about a minute. I know, only an 8 track but might work for your experiment.

 

[fredblue]

The first track on side 2 of the J Geils Band is mono on one track, I think front left but not sure, for about a minute. I know, only an 8 track but might work for your experiment.

is that "Stoop Down #39" on the Q8?
i only have the CD-4 and that's Track 1 on Side 2.

 

[Philip Spinner]

Yes, that's it. It blasts away in mono in one channel for about a minute and then opens up to 4 channel. At first I thought my tape was defective.

 

[fredblue]

Yes, that's it. It blasts away in mono in one channel for about a minute and then opens up to 4 channel. At first I thought my tape was defective.

fab, thank you, i'll check it out!

 

[sjcorne]

fab, thank you, i'll check it out!

I did it about two years ago using the archaic "Creative DTS-610 to CD Recorder" method. Here's the waveforms from that:




I've since gotten quite a bit better at doing these conversions (have also adjusted the separation pots on my demodulator and invested in a better recording interface), so I'll definitely take another crack at in the future. It's a great mix, BTW.

 

[fredblue]

I did it about two years ago using the archaic "Creative DTS-610 to CD Recorder" method. Here's the waveforms from that:

View attachment 39781


I've since gotten quite a bit better at doing these conversions (have also adjusted the separation pots on my demodulator and invested in a better recording interface), so I'll definitely take another crack at in the future. It's a great mix, BTW.

oh i've had the CD-4 a while it just got lost in the piles of stuff! i'll give that track a try tonight.

edit: playing it now, you're right the mix is great! very active!
⬅↖⬆↗➡↘⬇↙⬅

 

[fredblue]

I did it about two years ago using the archaic "Creative DTS-610 to CD Recorder" method. Here's the waveforms from that:

View attachment 39781


I've since gotten quite a bit better at doing these conversions (have also adjusted the separation pots on my demodulator and invested in a better recording interface), so I'll definitely take another crack at in the future. It's a great mix, BTW.

here's how it turned out thru the Grundig Quadro demodulator
(pots set to max separation) with faint piano reverb in both Front Right and Rear Right
and ever so slightly louder reverb in the Rear Left of the Front Left channel content,
all mercifully (and unusually!) with no distortion detectable in any channel.

tbh I doubt I could get much better separation than that with my current setup and would doubtless require a new cart, a different demodulator, the works in order to maybe get a small uptick in separation, if that's even possible with CD-4 I don't know, tbh its not something i'm willing or able to do right now.

if anyone wants to check out a sample clip drop me a line (stating points of view!)

 

[winopener]

I think you nailed correctly, and a different cart/demod could bring maybe a 3dB difference more, but not eliminate the sounds in the supposedly silent channels. These are the limits of the LP records (and the cartridge), there's nothing that can improve them so drastically in order to arrive at 1 channel sound, 3 channel silent.
CD4 = Discrete, as a record can be. Not more... better don't ask for what the media can't do.

 

[sjcorne]

Of course, if you're working on a DAW you can cheat and just delete the crosstalk on sections that are supposed to be silent, but I'm not sure how ethical that is.

 

[fredblue]

I think you nailed correctly, and a different cart/demod could bring maybe a 3dB difference more, but not eliminate the sounds in the supposedly silent channels. These are the limits of the LP records (and the cartridge), there's nothing that can improve them so drastically in order to arrive at 1 channel sound, 3 channel silent.
CD4 = Discrete, as a record can be. Not more... better don't ask for what the media can't do.

at the risk of tempting fate, i think i can say i'm totally happy for the first time with my CD-4 setup.
when i compare the demodulated results of the Grundig Quadro Vs my earlier attempts with the JVC 4DD-5 things are definitely improved; separations about the same, although each demodulator puts different emphasis on different elements, i almost always prefer how the Grundig handles things. most importantly i find the Grundig to have a smoother less distorted sound all round, less of the hollowed out feel i got out of the JVC and with a richer low end.. a big fan of the upped oomph for sure!

 

[fredblue]

Of course, if you're working on a DAW you can cheat and just delete the crosstalk on sections that are supposed to be silent, but I'm not sure how ethical that is.

oh you lil' devil..!!
hand on heart i have thought about it the last few years of fckin' about with the old Quad records.. but the one and only time i tried it (with that Paul Simon track with the harmonica, name escapes me at the mo) i hated the results of my pathetic post-SQ decoding fiddling about so much it tipped me over the edge into getting a Q8 deck and not only breaking the bank to get the Still Crazy After All These Years tape but breaking my back getting the Akai deck into my rig! phew that's a mini tank!

 

[JonUrban]

oh you lil' devil..!!
hand on heart i have thought about it the last few years of fckin' about with the old Quad records.. but the one and only time i tried it (with that Paul Simon track with the harmonica, name escapes me at the mo) i hated the results of my pathetic post-SQ decoding fiddling about so much it tipped me over the edge into getting a Q8 deck and not only breaking the bank to get the Still Crazy After All These Years tape but breaking my back getting the Akai deck into my rig! phew that's a mini tank!

That was "Night Game", the song about the baseball park.

 

[fredblue]

That was "Night Game", the song about the baseball park.

ah! that'll be the one!
the SQ so bad it forced me into Q8!

edit: you ne er said what the test was you wanted to try!