Digital file for decoder testing?

[n8nagel]

Does such a thing exist? FLAC or other file that I could play through a DAC and test my CD-4 decoder? It would have to be RIAA EQ'd as well as I don't see how to separate the decoder from general phono stage (Marantz CD-400)

I ask because I have never used this decoder as anything other than a 2 channel phono stage, nor do I know for sure my cartridge/stylus is good nor do I even have any known good media.

In other news: everything else is working great! The Marantz 4270 that I've been fighting with for several years now is working fine with the exception that the FM tuner drifts as the unit warms up.

 

[n8nagel]

Well, now this question is academic... as I just posted to a local group

HOLY (REDACTED) (REDACTED)! I found in my Pile o' LPs a SEALED RCA Quadradisc version of Shostakovich's 15th Symphony. Threw it on, dropped the needle, and THE RADAR LIGHT COMES ON
Houston, we have quad. I REPEAT WE HAVE QUAD.

I didn't even touch any of the adjustments on the CD-400 and only aligned the cartridge with the factory Technics gauge... usually things don't work this easily?

 

[surround.sound.enthusiast]

Excellent! CD-4 set-up can be fickle, plenty of members have had mixed experiences with it since their first encounters. But as both Quadfather and OldQuadGuy have said "follow the rules (requirements) for CD-4, and most problems disappear".

Now, as far as I'm aware, there aren't any digital test signals for CD-4, you'll only find them on the 45rpm set-up discs, or rare RCA, JVC, and Soundbird 12" discs (please correct me anyone). There are, however, SQ and QS encoded test tones available on OldQuadGuy's website: www.quadraphonic.info/SQandQS/

 

[furui_suterioo]

I wonder about the same thing myself, doesn't the Stereo Lab demodulating software need files with raw cd-4 needldrop? I like the idea of having the raw 2ch file available so it can be played through headphones or demodulated later.
There are some music files scattered on this thread:
https://www.quadraphonicquad.com/forums/threads/working-cd-4-software-demodulator.24900/I'm not sure which or if the files contain carrier signal or exactly how you would go about playing digital files through a demodulator, at a low volume possibly? I've wanted to try it but wouldn't want to overload the demodulator's phono input.

 

[surround.sound.enthusiast]

I think you're right, it would either have to be a needle drop with the carrier signal intact, or someone with a lot of time on their hands creating a modulated digital audio test file from scratch.

 

[jupp369]

see: Non-LP sources of CD-4 music