Working CD-4 (software) Demodulator!

[kfbkfb]

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]

http://www.phaedrus-audio.com/Groove_sleuth.htm^^^
New! - Strain-gauge cartridge preamplifier


Kirk Bayne

 

[Electric Moo]

Interesting strain gauge backstory. I knew Soundsmith make a strain gauge system, but wasn't aware of the history. Thanks!

 

[Electric Moo]

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

 

[kfbkfb]

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

 

[Electric Moo]

Ah, good to know! Thanks!

Just checked it out, interesting reading too. 24 bit/96 kHz mandatory format for their software.

 

[jupp369]

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]

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"
https://www.aes.org/e-lib/browse.cfm?elib=20544

Kirk Bayne

 

[Electric Moo]

I just want to be able to listen to my copy of Rick Wakeman's "journey to the center of the earth" !!

 

[quattro64]

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

http://www.phaedrus-audio.com/Groove_sleuth.htm^^^
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.

 

[quattro64]

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.

 

[kfbkfb]

Post #41 has info for running Stereo Lab software with Windows OS.


Kirk Bayne

 

[quattro64]

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...

 

[JediJoker]

I'm currently running Yosemite. :-(

I hope that computer's not connected to the Internet...

 

[quattro64]

I hope that computer's not connected to the Internet...

Not usually, no. I'm guessing by now it has some security issues, lol.

 

[JediJoker]

Not usually, no. I'm guessing by now it has some security issues, lol.

 

[quattro64]

Lolol!

 

[joelchip]

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"
https://www.aes.org/e-lib/browse.cfm?elib=20544

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]

(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]

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.