Working CD-4 (software) Demodulator!

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kfbkfb

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From the link in post #1 (DD turntable info):

under the User information & advice section,
requirements for making a good needledrop
of a CD-4 disc.


Kirk Bayne
 

kfbkfb

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Kirk Bayne
 

ummagumma

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Hi just checking in: does anyone know the status of the software CD4 demodulator?

I can probably needledrop a CD4 record with no eq if it's useful. I have an Empire 4000 DIII stylus, 4000 DIII cart, and an Empire 698 TT.

I'm guessing 24 bit/192kHz would retain the carrier signal?

Thx
 
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kfbkfb

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The CD-4 software demodulator is now available.

From the link in the first post, see: User Information & advice section which explains what is required for a CD-4 needledrop for the Stereo Lab software.

Yes, 24bit/192kHz would retain the carrier.


Kirk Bayne
 

jupp369

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96kHz result in triangles, 192kHz bring a fine sinus in the 30kHz, check it with Audacity.
Hope the software decoder will be implemented in a chip for media players.
As for me, I recorded all after the RIAA, getting a clean CD4 sound to the old JVC amp. from DVD with a bright 30kHz.
 

kfbkfb

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Richard Brice (developer of the CD-4 decoder) of Pspatial Audio would be the person to email about the 96kHz/192kHz issue.

Pspatial Audio is taking suggestions for other decoding modes for CD-4.

Details of the CD-4 decoder:
"A New Decoder for CD-4 (Quadradisc) Phonograph Records"


Kirk Bayne
 

quattro64

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So I'm guessing from this that the stereolab software can now handle straingauge cartridge EQ? :SB

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New! - Strain-gauge cartridge preamplifier


Kirk Bayne
I see an EQ setting 'Phono EQ P1 for strain guage/light carts' So I think this program will work now with all CD-4 cartridges.
 
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quattro64

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And, Does anyone know what is the minimum Mac OS sound lab will run on? Thanks!

EDIT: Found their help page. 10.12 Sierra is the minimum. I'm currently running Yosemite. :-(

May have to upgrade.
 
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quattro64

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Thanks Kirk,

That is a nice option to use a virtual machine. Yet, I think it is finally time for me to upgrade to at least High Sierra on that machine...
 

joelchip

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Richard Brice (developer of the CD-4 decoder) of Pspatial Audio would be the person to email about the 96kHz/192kHz issue.

Pspatial Audio is taking suggestions for other decoding modes for CD-4.

Details of the CD-4 decoder:
"A New Decoder for CD-4 (Quadradisc) Phonograph Records"


Kirk Bayne
Pspatial does have a software decoder, but you need to 'digitize' the recording by inputting the phono cartridge output directly into a Mic input, then to a .wav file. If your computer I/O trims off audio over 20khz, the carrier will be lost or compromised. Their decoding works really well and they have a great support staff that answers emails same day. I got great front/rear separation, but also a ton of distortion as soon as the carrier was detected and quad began. I gave up and donated all of my CD-4 discs to a quaddie. PSP also has a software QS, SQ and some other matrix decoders. They work the same way on digitized files from quad LP's and yield 3-5 db separation on those formats.
 

kfbkfb

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(true about the emails)

CD-4 records should be clean and should be played with a clean line contact/Shibata stylus and the overhang should be set properly.

In another post I mentioned that, even with a (non-CD-4) Shure V15 3 w/MR(line contact) stylus with correct overhang, my Technics SH-400 provides good surround sound, the only (isolated) distortion is due to the Shure missing much of the upper sideband of the FM carriers.


Kirk Bayne
 

joelchip

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I have an Ortofon Bronze (line contact) MM that will make it up to about 25-30khz. It cuts off the top end of the carrier also.
 
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