The “4th” A4 Number
Introduction to the “4th” A4 Number The “4th” A4 number is an essential measurement in this routine. While the first three A4 numbers identify the locations of A4’s 2nd, 4th, and 8th partials, the “4th” A4 number refers to the resultant width of the A3/A4 2:1 after it’s been tuned as a pure 4:2. This…