by Record-changer »
Sun Nov 06, 2011 5:03 am
More on CD-4:
In my entire life, I have seen only two CD-4 records that worked correctly. Both were in stereo stores demoing CD-4.
I own three records in CD-4 - all used. All of them are extremely noisy when played in CD-4. They were killed by their previous owners before I bought them at used record stores (I was a college student during the quad years, and had very little money for new records). Even the calibration record that came with the (used) demodulator was quite noisy.
This is not noise that could be a result of misadjustment of the arm. It was the result of extremely tiny motes of dust embedded in the record grooves. What was inaudible when the record was played with the demodulator bypassed sounded like crashes when played with the demodulator on. Snap crackle pop! A stereo record with such noises would have to have visible scratches on it.
I once saw a CD-4 record become contaminated in a stereo store. It was playing, and I was listening to it. A woman stopped at a mirror on the wall next to the display and put on some face powder. A few seconds later, the record started making the snap crackle pop sounds. The salesman ran over to see what was wrong. He asked me if I had touched the turntable. I said, "No. It started after a lady put some powder on her face by that mirror." He then stopped the player and cleaned the record. The entire record then made the crashing sounds, not just the part that was played after the powder was used. He was unable to remove the noises.
In addition, play with a standard stereo cartridge reduces the amplitude of the carrier, causing a hissing that people call "sandpaper quad."
The main fault of the CD-4 system is that is was not robust enough to stand up to normal use.