All the information I've seen, including inserts in some QM records, used Sansui encoders! A Japanese-speaking friend translated for me the fact that the Sansui encoder (without referring to QS) was employed in the mixing of the record.
TOSHIBA 4 channel QM decoder
- Thread starter bigbillquad
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Yes could be, but I remember seeing a post showing a QM insert with an EV-4 logo, can't read Japanese so don't know what it said. I remember reading elsewhere about QM being EV-4. check here Quadraphonic Systems The decoder has different settings that I'm sure one at least would be QS (or RM). Remember that RM and EV-4 are very nearly the same, coefficients are very close.
I think i got it right this time.
CAUTION: This little box must not be opened or it will be ruined!
This decoder is in fact a sound processor only for the back channels.
It does nothing to the front channels.
This little box is a reverb unit like the one found in older guitar amplifier. it is re-creating the echoes and reverbs found in different rooms according to settings and speakers locations as shown in the diagrams. It has a 2 channels input (to connect to any amplifier REC out) and only output the effect back channels (to connect to external amplifier and speakers connected to the output terminals or use the internal amplifier).
Curious... what would be ruined & how did you come to that conclusion?
(or maybe you're just being silly like I am too often.)
It is quite possible it has some effect on the front chs. As you can see on pg 2 it shows an input (probably tape out from a receiver) and a front ch output (probably going to the tape in on the same receiver). I doubt that it does much to the front chs, but if QM=EV4 there is some in phase blending involved.
Again it says the decoder "picks up" reverberant & indirect sounds & says nothing about artificially creating reverb or delay. I'm familiar with ye olde spring reverbs & that little metal box is far too small to contain one.
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furui_suterioo
Quad & 70s Enthusiast
Another one:
https://www.jauce.com/auction/f463380377
https://www.jauce.com/auction/f463380377
Wow people must be cleaning out their closets! This one looks in a little rougher shape than Bills.
I had forgotten the original name of Toshiba that being Tokyo Shibaura. Like many companys around the world sometimes the geographical location has an importance. Shibaura is a district of Minato ward in Tokyo. Mitsubishi motors & other big mfg firms call it home.
This is true. I have a demo record, put out by Toshiba and Sansui, that use tracks from QM-labelled records. It's a 4 cut EP called "QS 4-channel Hit Deluxe". It kicks booty through the SM.
Hi. All
I`ll need to put this project on the back burner and work something out latter I will do it BUT my man cave needs my attention.
BBQ...
I`ll need to put this project on the back burner and work something out latter I will do it BUT my man cave needs my attention.
BBQ...
Soundfield
1K Club - QQ Shooting Star
You can’t just leave us in suspense BBQ!! You’ve got people on three continents who want to know what’s in the little mysterious “QM decoder unit” box! Just grab your screwdriver and camera - it’ll only take a couple of minutes!
All I know about the QM format I posted previously in response to yet another of your finds! –
QM Matrix Decoder
How you come across all this obscure staff amazes me, but it’s always fascinating, thanks!
MidiMagic
2K Club - QQ Super Nova
- Joined
- Jul 5, 2010
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If that is a spring reverb unit (and I have one that looks like that), there are two springs inside, with two driver transducers at one end and two receiving transducers (similar to phono pickups) at the other end. There are no electronics in the box.
The transducers rotate one end of a tightly wound coil spring back and forth. The sound waves travel along the spring through rotation of each coil in turn. The rotation of the other end of the spring is picked up by the transducers and amplified. It is a mechanical delay line.
If the spring is bent so any two coils touch each other, it would cause noise and distortion.
If you just take the unit out and turn it over, one side of that "box" is usually open.
The transducers rotate one end of a tightly wound coil spring back and forth. The sound waves travel along the spring through rotation of each coil in turn. The rotation of the other end of the spring is picked up by the transducers and amplified. It is a mechanical delay line.
If the spring is bent so any two coils touch each other, it would cause noise and distortion.
If you just take the unit out and turn it over, one side of that "box" is usually open.
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I had one sansui equalizer with an echo unit like that inside and it was defective.
I've had a Pioneer & Fender spring reverb before. The actual spring units are quite large, 8">10" long. The box in the QX decoder is tiny tiny. That's why I suspect it is not a spring reverb. And if Toshiba was going to the trouble to incude one, surely they would promote it as a feature.
Soundfield
1K Club - QQ Shooting Star
Absolutely, of course it's not a reverb unit. Apart from the fact that you couldn't possibly fit one of those spring lines in a box that size, you are right, the Toshiba blurb clearly describes this decoder as a "Quadra Matrix Decoder". QM was a registered standard of matrix format in Japan. You cannot decode a matrixed recording (QM or otherwise) by sticking it though a wobbly spring!!
Yeah too little, and not applicable I’d imagine; but it’s wild to accidentally kick a guitar amp turned up with one of those spring reverb tanks- bwoooongggzkgvzzz!!! 
I read the the document provided by "par4ken" on quadraphonic system and on most QM decoding equations including Dynaquad and Dolby, the following apply:
Dynaquad: Front left = left and Front right = right, then the equation for the Rear channels have matrix equations Rear left = .86L - .5R and Rb = -.5L + .86R
QM dolby: Left = l, Right= r, Front = (.71l + .71r), Rear = delay (.71j - .71rj)
(there is a delay on the back channel)
With those equations, there is no decoding of the Front channels, only the Rear.
The instructions are straight forward in the manual: All you need is a SC-410 and 2 speakers.
The SC-410 have effects selections, those effects include: Hall, Studio, Surround and Stage. These all involve reverb and delays to mimic the sound caracteristics of various listening places. We have these settings on every 5.1, 6.1 and 7.1 modern multichannel decoders.
So the little box certainly contains the effects module or circuits for 2 reasons:
1- if it's mechanical, it must be protected against shock and electronic noises.
2- if it's electronic, which i doubt, it must be well shielded as early electronic reverb devices where rather noisy.
I make all my assumptions on 40 years of experience in electronics and sound systems and i'm still learning.
Sonik, buy a parts unit, and open that thing up, to see what’s in there
I don't think I could afford the Zen Market shipping from Japan!Sonik, buy a parts unit, and open that thing up, to see what’s in there
Soundfield
1K Club - QQ Shooting Star
And so did a myriad of other matrix decoders and synthesisers because those types of effects are easily produced from variations of the Hafler connection technique using a handful of resistors. They arise because of the relationships between the phase relationships of direct and reverberant sound in a stereo or encoded pair. No reverberation unit is required to generate them after the fact, they already exist in the recording, which is why no quad decoder I’ve ever come across uses such a thing. Can you identify any that do? Adding a delay in the rear channel is a different matter and has latterly been used in modern day surround sound systems to increase apparent room size but such uniform delay does not introduce any artificially created reverberation.
What the heck is QM Dolby? QM is neither Dynaco or Dolby matrix. Also from the Midi-Magic Quad Systems page:
If you refer back to that page & section it can be seen that QM involves both encoding of front & rear chs, & matrix decoding of both sets upon playback. The QM/EV4 is has a relatively wide front sound stage, narrow rear left to right, & good separation of front to back. That is neither Dolby or Dynaco.
The earliest Sansui decoders such as the QS-1, QS-500B, and others also had similar modes of operation. The Sansui had not one but two concert hall modes. These were easy tricks back then, various matrix blending, EQ tailoring & all done with out any delay or reverb added. You're right delay is common on modern receivers but that the Toshiba was not one of them. Dolby Matrix with delay had not even been invented then so there's no reason to expect QM would be in compliance with Dolby.
I base my comments on 50+ years involvement with surround sound & audio electronics.
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