Thanks wareika, I'd also say 83 or 82 with the On-U-Sound 10" in mind.wareika wrote:For general release (no dubplate or 78rpms) the 10" format appeared during the 80's (circa 83/84) on Channel One related labels (Hit Bound, JJ, J&L and so on).
Volume of a disc is approximately thickness*Pi*radius*radius so thickness x Pi x 0.25 x 0.25 for a 10" and thickness x Pi x 0.30 x 0.30 for a 12" so the difference is a factor 0.0625 against 0.09wareika wrote: I have the feeling that the real reason is more linked with the raise of oil price (first in late 70's and in recent years). If you consider that you can put the same extended tune either on a 10" or a 12" disc, the 10" format saved a lot oil. I did the calculation once and from memory with the same amount of vynil you press either 2 x 12" or 3 x 10"...
wareika
With 3 10" 0.1875 and with 2 12" 0.18, you were right