Fast1one
10+ year member
CarAudio.com Veteran
To lower the huge peaks in the upper band (80z ish, different for every driver). Stuffing helps to reduce them, but also makes the apparent length longer. So in some cases we shorten the length, then add stuffing..."you probably want to make the line slightly shorter and add stuffing until you get the desired response and impedance curve. Stuffing the line will change the speed of sound which will also change the apparent line length."^^^^
why make it shorter, then add stuffing to make the line seem long again?