Not sure about the noise but the numbers on the arrows tell you the size of the shafts. The first 2 numbers tell you the outside diameter of the shaft in 64ths of an inch. Ie. 16/64 and 18/64 based on the two examples you gave. The second 2 numbers tell you the wall thickness of the shaft in 1000th of an inch.
Basically the thicker the wall and larger the diameter the stiffer the arrow.
Basically the thicker the wall and larger the diameter the stiffer the arrow.