Commercial Matrix Quadraphonic Cassettes?

[doity]

FWIW

Sony had a cassette deck that promoted matrix recording and playback for matrix encoded cassettes.(Symphase)

And I believe IIRC , some Nakamichi decks may have been excellent for head azimuth alignment.

I think that Nakamichi had only a few with manual adjustment for playback. They had a little green light at the 12:00 position that I think would light up when in perfect alignment. Usually the best setting was at 12:00, so I kind of am skeptical about how much this feature got used by most people. But, I had the Nak Cassette Deck 1 a long time ago and it ‘did’ work well on tapes made on other decks and the knob really came in handy and worked well.

The Nak Dragon had automatic correction but of course you paid for that feature. I remember when I was younger that the Dragon had an almost mythical status. I heard a lot about it even though no one in my immediate circle could had even dreamed about affording such a machine. The Marantz SD930, which I own, was a bit cheaper and did the azimuth correction a bit differently than the Dragon. My understanding is that with the Dragon there was some lag.....or maybe it did a test first and then set it, kind of like those decks that had the auto bias and EQ that would take into account the different tapes on the market. The Marantz adjusts it on the fly and it is so fast that you never heard any fluctuations in the audio.

 

[kfbkfb]

There's a .wav file w/SQ directional test tones [I think I got it from here in QQ, but I don't recall who provided it], record this on a stereo cassette deck, then play it back and (manually) adjust the azimuth and see how the SQ decodes w/directional shifts.


Kirk Bayne

 

[doity]

There's a .wav file w/SQ directional test tones [I think I got it from here in QQ, but I don't recall who provided it], record this on a stereo cassette deck, then play it back and (manually) adjust the azimuth and see how the SQ decodes w/directional shifts.


Kirk Bayne

How do the SQ cassettes decode from a cassette tape? I have almost zero experience with SQ and am curious as to how well it works. Though with a classical recording there probably won’t be a lot of the typical ‘quad experience’ that you usually get from a similiar rock recording in SQ quad.

 

[fizzywiggs41]

Being somewhat curious, and after finally getting around to using my newly serviced Tate Tetrasound, I have sought out some of the SQ cassettes to try out. The BASF ones seem harder to find so I looked at the offerings from Angel. I found a nice ‘Four Seasons’ by the London Philharmonic on XDR cassette with the double circle logo, which is supposed to denote that it is in SQ.

Not expecting too much as I have read that azimuth issues might get in the way of properly decoding, but I have a deck that automatically corrects for azimuth differences so that shouldn’t be an issue. Not the Dragon, but a Marantz deck. I ‘think’ that only two decks ever did this, but there are a couple with manual adjustment that seem to work well. Will give a report back on the results.

FWIW I always wanted a couple more of those BASF SQ cassettes. But like you say they are hard to obtain.

Back I the latter 70's ,Acanta Records a division of Bellaphon Records reissued some of those SQ recordings on both LP and cassette.
So you might try Acanta /Bellaphon Records.

Here's a picture of the back cover of one of their LP's ,denoting that it's also available on cassette. (1978)

Cassette # BA 33.173

Also one more , quadro cassette # BA 33 .170 , Romantic Seasons , Warner Twardy Orchestra (Super HIFI Dancing)

Anyways ,it's worth a try.

 

[MidiMagic]

Let's look at what an azimuth misadjustment does to the encoded recording when played back:

Adjustment of the azimuth changes two values that affect the encoded program.

1. One channel can be a period of time ahead of or behind the other.
2. The head gaps are slanted to the track so the frequency response is lowered.

Amazingly, when I was repairing such recorders, I came across heads where the gaps were misaligned, and the best channel phasing was at an angle different from the best frequency response. The only cure is to replace the head.

The effect if the frequency response changes could unequally affect the amplitudes of the two signals at higher frequencies.

The effect of the different timing of the two tracks is to phase shift material that is on both tracks relative to each other.

The phase shifts are frequency dependent, with higher frequencies affected more than lower frequencies..
The tape speed also affects the phase shift. 1.875 in/s has twice the phase shift as 3.75 in/s.

So a mismatched azimuth adjustment will cause the high frequency decoding to be blooey while lower frequencies decode OK.

What happens with RM when the phase shifts at a high frequency by 90 degrees.?
- Any sound source to the front or the back will be moved to the center of the room.
- Any sound source centered in the room will move to the front or back.
- Any sound straight left or straight right is unchanged.

What happens with SQ when the phase shifts at a high frequency by 90 degrees.?
- Any sound source at center front or center back is moved to left back or right back.
- Any sound source at left back or right back is moved to center front or center back.
- Any sound at left front or right front is unchanged.

Notice that the effect on SQ is twice that on RM.

Also note that none of these discrepancies happen if the same head with the same adjustment recorded the cassette and played it back.

If a cassette is Dolby B encoded with Dolby Surround signals, the surround is encoded first, and then the Dolby B is put on the entire tape.
When playing it back, you play it with the Dolby B switch on and then run the output to the Dolby Surround decoder.

 

[fizzywiggs41]

Let's look at what an azimuth misadjustment does to the encoded recording when played back:

Adjustment of the azimuth changes two values that affect the encoded program.

1. One channel can be a period of time ahead of or behind the other.
2. The head gaps are slanted to the track so the frequency response is lowered.

#Your Number 1. , I fail to understand . Are you sure your not referring to a 2ch tape ? You know, one channel left and the other right.
Which an encoded matrix 2ch (4 ch helical) would not be an accurate explanation of one falling behind the other.
Do you mean 2channels falling behind the other two encoded ?
And if so how does two encoded channels on one track affect the final 4ch matrix playback ?
Keeping in mind the 4 corners left , right , leftrear, and rightrear should be mostly retained .(the odd dropout would occur)
Center channels be they front , back , or sides are actually "phantom" sounds on a 4 channel speaker system.

Anyway , I'll let you explain.

 

[MidiMagic]

#Your Number 1. , I fail to understand . Are you sure your not referring to a 2ch tape ? You know, one channel left and the other right.
Which an encoded matrix 2ch (4 ch helical) would not be an accurate explanation of one falling behind the other.
Do you mean 2channels falling behind the other two encoded ?
And if so how does two encoded channels on one track affect the final 4ch matrix playback ?
Keeping in mind the 4 corners left , right , leftrear, and rightrear should be mostly retained .(the odd dropout would occur)
Center channels be they front , back , or sides are actually "phantom" sounds on a 4 channel speaker system.

Anyway , I'll let you explain.

I am referring to the final 2-tracks of an encoded stereo cassette that play at one time.

When one channel falls behind the other due to head misalignment, it affects the phase between the two channels. This changes the timings of the two parts of the "helix" when they are matrixed back together in the decoder.

The encoding is called helical only because it makes the stylus travel the record groove in a helix,

To get the helical encoding of SQ (e.g. RB), the left channel gets the RB signal 90 degrees behind the RB signal the right channel gets.

j = 90 degrees ahead of a value with no j factor.
-j = 90 degrees behind a value with no j factor.

L = LF - .71 LBj + .71 RB

R = RF - .71 LB + .71 RBj

So RB is on both the left channel and the right channel of the 2-ch tape, with a phase difference between them.

If one track is then delayed, the relationship between the left and right channel RB signals is no longer 90 degrees. So the decoder uses the changed phases to create a modified decoding.

And again, this would have a smear effect because the high frequencies have more time error than the low frequencies have. The decoding of the high frequencies would be smeared more than the decoding of the low frequencies has.

 

[MidiMagic]

FWIW I always wanted a couple more of those BASF SQ cassettes. But like you say they are hard to obtain.

Back I the latter 70's ,Acanta Records a division of Bellaphon Records reissued some of those SQ recordings on both LP and cassette.
So you might try Acanta /Bellaphon Records.

Here's a picture of the back cover of one of their LP's ,denoting that it's also available on cassette. (1978)

View attachment 73729


Cassette # BA 33.173

Also one more , quadro cassette # BA 33 .170 , Romantic Seasons , Warner Twardy Orchestra (Super HIFI Dancing)

Anyways ,it's worth a try.

Bellaphon - that's the label my other Vangelis recordings are on.

 

[fizzywiggs41]

Bellaphon - that's the label my other Vangelis recordings are on.

I believe Bellaphon is a record label out of Germany .

 

[fizzywiggs41]

Yesterday I spent some time looking in an old box of prerecorded cassettes , to see if I still had some of those Angel double circle SQ ones.

Although I did not find any , I did find a lot of other surround and quad format encoded cassettes.

Some that are Dolby (MP) ,EV-4 , SQ , SQ* , QS , DY-4D , Shure HTS , Circle , Binaural 3D , Spatilizer , Chace Stereosurround, and UltraStereo surround . Also Holophonics and UHJ.

Now back in the late 90's I had most of these on CD . Unfortunately times got tough financially , so I sold off a large number of those I had in CD .


*(suspected SQ)

 

[doity]

Yesterday I spent some time looking in an old box of prerecorded cassettes , to see if I still had some of those Angel double circle SQ ones.

Although I did not find any , I did find a lot of other surround and quad format encoded cassettes.

Some that are Dolby (MP) ,EV-4 , SQ , SQ* , QS , DY-4D , Shure HTS , Circle , Binaural 3D , Spatilizer , Chace Stereosurround, and UltraStereo surround . Also Holophonics and UHJ.

Now back in the late 90's I had most of these on CD . Unfortunately times got tough financially , so I sold off a large number of those I had in CD .


*(suspected SQ)

Which ones of the bunch are the SQ ones for sure? I have a big cassette library and I likely own a few of these. Thanks!

 

[fizzywiggs41]

The PINK FLOYD -DSOTM IMPORT (EMI/Electrola) -Germany , BASF -Germany , AIG "Sounds Of Canada" , Tangerine Dream -Zeit , Atem , and 3 tracks on the Best Of T D , and Carol's For Christmas Eve
(EMI/Seraphim)-Canada .

The SQ suspected ones are Messiah (MMG/CBC Records) , Purlie O C , The Enoch Light (1 of 2 tapes) .

The Michael Stearns, Best of .. contains 3 quad tracks in either UHJ or a mix down from Q4 , and both The E Power Biggs and Reelin' In The Years Volume 4 are just suspect.

Both the Eberhard Schoener meditation , and Boulez Bartok for 4 Orchestras are not SQ .
But would be if they were the earlier 73 Versions .

I Hope that is understood.

 

[kfbkfb]

Some that are Dolby (MP) ,EV-4 , SQ , SQ* , QS , DY-4D , Shure HTS , Circle , Binaural 3D , Spatilizer , Chace Stereosurround, and UltraStereo surround . Also Holophonics and UHJ.

I had only heard about EV Stereo-4 (demo tape), rumored SQ and Dolby MP encoded compact cassettes, I didn't realize so many other matrix encoding systems were used (maybe improved compact cassette manufacturing methods made matrix encoding more practical).


Kirk Bayne

 

[doity]

The PINK FLOYD -DSOTM IMPORT (EMI/Electrola) -Germany , BASF -Germany , AIG "Sounds Of Canada" , Tangerine Dream -Zeit , Atem , and 3 tracks on the Best Of T D , and Carol's For Christmas Eve
(EMI/Seraphim)-Canada .

The SQ suspected ones are Messiah (MMG/CBC Records) , Purlie O C , The Enoch Light (1 of 2 tapes) .

The Michael Stearns, Best of .. contains 3 quad tracks in either UHJ or a mix down from Q4 , and both The E Power Biggs and Reelin' In The Years Volume 4 are just suspect.

Both the Eberhard Schoener meditation , and Boulez Bartok for 4 Orchestras are not SQ .
But would be if they were the earlier 73 Versions .

I Hope that is understood.

The Surround Discography only lists the Japanese QS cassette tape for Dark Side. Do you know something that everyone else doesn’t know?

 

[fredblue]

The PINK FLOYD -DSOTM IMPORT (EMI/Electrola) -Germany , BASF -Germany , AIG "Sounds Of Canada" , Tangerine Dream -Zeit , Atem , and 3 tracks on the Best Of T D , and Carol's For Christmas Eve
(EMI/Seraphim)-Canada .

The SQ suspected ones are Messiah (MMG/CBC Records) , Purlie O C , The Enoch Light (1 of 2 tapes) .

The Michael Stearns, Best of .. contains 3 quad tracks in either UHJ or a mix down from Q4 , and both The E Power Biggs and Reelin' In The Years Volume 4 are just suspect.

Both the Eberhard Schoener meditation , and Boulez Bartok for 4 Orchestras are not SQ .
But would be if they were the earlier 73 Versions .

I Hope that is understood.

i'll eat my top hat if either of those Tommy tapes are the QS-encoded Quintaphonic mixes!

 

[Owen Smith]

i'll eat my top hat if either of those Tommy tapes are the QS-encoded Quintaphonic mixes! ✌

Given the quintaphonic mixes relied on the dedicated Centre channel on the film magnetic print, plus QS encoding on the film Left and Right channels, it's impossible for cassette or any other stereo medium to carry it.

 

[par4ken]

I am referring to the final 2-tracks of an encoded stereo cassette that play at one time.

When one channel falls behind the other due to head misalignment, it affects the phase between the two channels. This changes the timings of the two parts of the "helix" when they are matrixed back together in the decoder.

The encoding is called helical only because it makes the stylus travel the record groove in a helix,

To get the helical encoding of SQ (e.g. RB), the left channel gets the RB signal 90 degrees behind the RB signal the right channel gets.

j = 90 degrees ahead of a value with no j factor.
-j = 90 degrees behind a value with no j factor.

L = LF - .71 LBj + .71 RB

R = RF - .71 LB + .71 RBj

So RB is on both the left channel and the right channel of the 2-ch tape, with a phase difference between them.

If one track is then delayed, the relationship between the left and right channel RB signals is no longer 90 degrees. So the decoder uses the changed phases to create a modified decoding.

And again, this would have a smear effect because the high frequencies have more time error than the low frequencies have. The decoding of the high frequencies would be smeared more than the decoding of the low frequencies has.

Can you say "Double Helical Modulation"!

 

[fredblue]

Given the quintaphonic mixes relied on the dedicated Centre channel on the film magnetic print, plus QS encoding on the film Left and Right channels, it's impossible for cassette or any other stereo medium to carry it.

my comment was made somewhat with tongue in cheek since people have been saying the Tommy OST album's QS for so many years when it patently isn't

 

[fizzywiggs41]

The Surround Discography only lists the Japanese QS cassette tape for Dark Side. Do you know something that everyone else doesn’t know?

Yes.

 

[fizzywiggs41]

my comment was made somewhat with tongue in cheek since people have been saying the Tommy OST album's QS for so many years when it patently isn't

Adam ,

Patently no , but somewhat interfered with as with the inclusion of the center( 5th mono) channel attests to . It's still 4channel QS though . Just not a standout QS QUAD recording.
FWIW there're are a few other QS encoded Albums in the same league.