Non-LP sources of CD-4 music

QuadraphonicQuad

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No Quarter

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Hi, just got my Marantz 4400, CD-400B and 4-channel pickup up and running, and have bought a few LPs on ebay. And it sounds amazing I think, especially live performances like Elvis in Madison Square Garden. This of course gives me appetite for more music. Without being too technical myself, the CD-4 is "just" music with the rear signal in a higher frequency area, right? If so, are music files like that available on CDs? On Youtube? Is there a Spotify for CD-4 music?

I've tried to play some youtube videos that claim CD-4, but the CD-400B box does not convert to quad, and the "radar" light doesn't light up.

Thanks
 

furui_suterioo

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Hi, just got my Marantz 4400, CD-400B and 4-channel pickup up and running, and have bought a few LPs on ebay. And it sounds amazing I think, especially live performances like Elvis in Madison Square Garden. This of course gives me appetite for more music. Without being too technical myself, the CD-4 is "just" music with the rear signal in a higher frequency area, right? If so, are music files like that available on CDs? On Youtube? Is there a Spotify for CD-4 music?

I've tried to play some youtube videos that claim CD-4, but the CD-400B box does not convert to quad, and the "radar" light doesn't light up.

Thanks
CD-4 demodulator will only work with CD-4 records, unlike SQ and QS which will work with any stereo source. The rear channels on a CD-4 record are actually summed with the front channels and only the difference signal is in the higher frequency carrier so that there is no loss of sound when played in 2ch.
 

No Quarter

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CD-4 demodulator will only work with CD-4 records, unlike SQ and QS which will work with any stereo source. The rear channels on a CD-4 record are actually summed with the front channels and only the difference signal is in the higher frequency carrier so that there is no loss of sound when played in 2ch.
But a CD-4 LP can be recorded on a 4 channel tape recorder, and played with full effect? Can't the sound, including the high frequency carrier be digitized and then shared?
 

par4ken

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But a CD-4 LP can be recorded on a 4 channel tape recorder, and played with full effect? Can't the sound, including the high frequency carrier be digitized and then shared?
A four channel tape recorder does not have the necessary frequency response to record the high frequency carrier. It can obviously be recorded after demodulation by the CD-4 Demodulator onto a four channel tape.

It is possible to record the LP digitally if the sample rate is high enough, ie. 96 or 192 KHz. Some here have done it, the files can be played back (and recorded from) a modified CD-4 Demodulator. Others have recorded the LP flat and then used software to decode it, there is a thread about that here as well. The software runs on Mac.
 

Doug G.

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You should search out and read material about how CD-4 works. It will lead to a much better understanding and less mystery.

Doug
 

MidiMagic

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You Tube does not have the bandwidth to carry the carrier.
 

jupp369

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s me appetite for more music. Without being too technical myself, the CD-4 is "just" music with the rear signal in a higher frequency area, right? If so, a
CD-4 is like Stereo Radio, but instead 27kHz they used 300kHz (no higher frequency in the rear). You can easily record it to Computer after the first amplifier (RIAA), but that need a peace of wire. You have to play it back at the same place, before the frequency filters and the Demodulator circuit. I recorded all my CD-4 on computer with Audacity and cleaned them (.wav 24/192kHz (not lower!!))
YouTube plays mpeg and mp4 or variations from them. so they are limited to 2x 24kHz. Take a closer look with Audacity zoom if you see the 30kHz in thoose "CD-4" files.
 

jupp369

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I recorded all my Quadradisc without problems and I play them from Data-DVD oder media-player without any loss.
Of course there are many traps:
24/192kHz WAV is needed or you get triangles instead a fine sine. Audacity is a useful tool with it's repair function.
Don't connect any HDMI, the handshake will limit your output to 20kHz! Use RGB.
And you need a new wire (need 2 out and 2 In = 4) soldered just behind the first amplifier after phono input, the RIAA equalizer. I did with 5 / 3 amplifiers from JVC and Panasonic without problem.
With my old XP compi that was no problem, but win7 and higher has limiters for In and Out. So I use now an external analog - USB made for musicians (Focusrite Scarlett 2i2 = 150$) and I'm very satisfied, no hum, direct USB - wav.
Sorry can't send you a sample, because yahoo limits all attachments to 25MB.
If you want to do it, ask more info.
 
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