Here is the best dissertation I could find on the subject in layperson's terms.
http://pspatialaudio.com/pvc.htm
As Regan said, "Facts are funny things." MFSL is a marketing firm. I have purchased their stuff since the early 80's. I have the completes Beatles set and the complete Stones Set as well as several UHQ discs like Crime of the century. Their game was to try and use virgin vinyl and better pressing plants so they could lower the gain so everybody's cartridge had an easy time tracking, and boost the bass which a lot of us complained about. Unfortunately, the lower gain created records that got unacceptably noisy if treated anything but absolutely perfect. Today's MFSL when compared to Analog Productions and a lot of the old European classical stuff is second rate. It is better than routine stuff for sure but it is not the last word and I certainly do not plan on buying any of the new UHQ records for that kind of money especially when I can get most of the stuff the market in high def digital down loads. However their PVC is compounded makes no difference. The very small quantity of carbon black added to PVC 0.2% makes absolutely no difference in the quality of the sound so using a substitute probably means nothing. As long as virgin vinyl is used the quality of the pressing is determined more by technique and cleanliness. By the way as you can read in the link above most of the stuff compounded into the vinyl has nothing to do with sound quality but rather to prevent problems that occur with the process.
As Regan said, "Facts are funny things." MFSL is a marketing firm. I have purchased their stuff since the early 80's. I have the completes Beatles set and the complete Stones Set as well as several UHQ discs like Crime of the century. Their game was to try and use virgin vinyl and better pressing plants so they could lower the gain so everybody's cartridge had an easy time tracking, and boost the bass which a lot of us complained about. Unfortunately, the lower gain created records that got unacceptably noisy if treated anything but absolutely perfect. Today's MFSL when compared to Analog Productions and a lot of the old European classical stuff is second rate. It is better than routine stuff for sure but it is not the last word and I certainly do not plan on buying any of the new UHQ records for that kind of money especially when I can get most of the stuff the market in high def digital down loads. However their PVC is compounded makes no difference. The very small quantity of carbon black added to PVC 0.2% makes absolutely no difference in the quality of the sound so using a substitute probably means nothing. As long as virgin vinyl is used the quality of the pressing is determined more by technique and cleanliness. By the way as you can read in the link above most of the stuff compounded into the vinyl has nothing to do with sound quality but rather to prevent problems that occur with the process.