There were only like 500 original orders for the new Dorren CD-4 demod, since that is what set its price. Then as time went by with no demod, people pulled their orders due to the money being needed elsewhere. So if Involve were to do a CD-4 unit, they'd have to expect VERY low sales numbers - and as for software, although SQ had the most material released, CD-4 was 2nd and should we expect everyone to be using CD-4 LP's or could maybe Involve arrange some licensing agreement where the CD-4 albums were digitized at 98kHz or 192kHz in LPCM from pristine albums that have been cleaned up - so even super rare CD-4 LP's could be released? And as I mentioned in my prior post, Spectral Replication could be used to extend the bandwidth of CD-4 to the full 20kHz instead of the 15kHz cut off (which was more like 10 or 11 kHz on most demodulators. The carrier signal, once demodulated, wouldn't need to be spectrally replicated since we can't really hear directionality at those high frequencies - so the mono HF baseband signal would do. The bass could be taken down to 20 Hz too since the official CD-4 spec was 30 Hz. Down there I would add phase shifts of a few degrees between each channel to make the bass sound more natural since bass was almost always recorded in mono on all LP's.
If, in transcribing the CD-4 LP's to LPCM discrete matrix files (since CD-4 was really a discrete matrix and not a true discrete system) the LP's baseband RIAA EQ and the HF FM/PM/FM carriers and JVC's ANRS NR system were all pre-decoded, the resulting CD-4 digital decoder would need much less circuitry - and the, what, 40ms delay between the baseband and HF carrier could be pre-processed too - the CD-4 digital demod would just have to demodulate the carrier and then dematrix the sum and difference baseband and carrier signals. And there would be no worries of patent licensing since all the patents have expired - only the Spectral Replication would need licensing.
of course, it would be a major undertaking just to get the rights to digitize the LP's and make them available for download. But really, this is just babble because it ain't gonna happen - I do not even believe that Lou Dorren's demod will ever be made available - it's just a gut feeling but one I have strong faith in. If the demod does become available everyone can post that I'm an ***** and make fun of me - and I'll be first in lie to do so.
one thing I would like to see is receivers built with the ability to have new surround decoders downloaded into their DSP chips, kind of like Sony Vegas or Photoshop. So if someone decided to make a DSP CD-4 demod, you could just upload it to the receiver and delete it at any time - or, if memory allowed, daisy chain them, like a DBX or Dolby SR decoder with a true QS Qunitaphonic decoder for Tommy - or Cinema Digital Sound for special releases, if we could get them, of **** Tracy and T2 - or a Todd-AO decoder for 5 speakers across the front with Perspecta surrounds, etc...
Martin Willcocks, who was the sole inventor of the Tate DES, when I talked to him about 2 years ago, had designed a 16-pole 90 degree phase shifter and said that with DSP it could easily become a 50 or 60 pole phase shifter - and he had also come up with new decoding modifying matrixes for the B- Matrixes applied to the Matrix Multipliers in the DES - they were designed to deal with the odd phase relationships that the Position Encoder and London Box could create and since the SQ system and DES is a 3-Axis decoder (QS and all others are only 2 axis on the Energy Sphere) and since the DES can recognize and decode all three axis simultaneously, a multi-band (like the QSD-1) decoder could 'rotate' between the different SQ modifying matrixes in each band on SQ encoded recordings with very complicated phase relationships, like the Buddy Rich CD and LaserDisc or David Essex's 'Rock On'. While he is no DSP engineer, Martin said that talking to DSP engineers made him think that 2 SHARC chips would be enough for it. Plus features like adjustable 2-channel stereo-to-SQ synthesis could be added along with phase correction for poorly aligned LP systems and a 5-10 ms look ahead so everything would be decoded before reaching the speakers. Boosts and rotations of the energy sphere and phase could be done too to make other decoders, like EV-4 (both versions) and correct Dolby Stereo decoding which the Fosgate Tate does not do - and the DSP receiver system would have 8 speaker feeds, as Ben Bauer always wanted for SQ since we cannot hear pair-wise mixed phantom side images- only Aphex ever implemented 8 channel outputs in their AVM-8000 SQ decoder they made in 1986 - unfortunately, it was a gain riding SQ decoder and not a true cancellation decoder so it didn't perform well, providing only 10db of separation between channels, which they did to reduce audible side-effects of the gain riding. Their later, true cancellation decoder for Dolby Stereo films, the ESP-7000, also had 8 speaker feeds, including center back (which makes me wonder how Dolby and THX got a patent on Dolby EX since the idea was obvious and had clear prior art - Plus PanaLogic had presented Jurassic Park with a center surround in an Australian theater back in 1993 using their PanaLogic decoder)
OK, as typical, I've babbled on too long - I have CBS's Quadraphonic Gala LP playing via my Fosgate Tate (the LP was originally produced to show off the Paramatrix decoder, but we all know how that went). Anyway, the music has kept me writing, but its over now - Maybe the CD's of Chase or Annie should be played next???
BTW, does anyone have a DTS encoded or BD/DVD-A encoded recording of an SQ album decoded by Peter Scheiber's 360 Degree Spatial SQ decoder? I've always wanted to hear that decoder and I've never had the opportunity. Nor have I ever found the extensive white paper he wrote about its inner workings.
