In answer to a PM asking if all a person had to do was put the new diaphragm on the pins and bolt it all back together.

I always run the requisite frequency sweep to ensure there are no unwanted characteristics. Before re-assembly I hit the gap with 120 psi of air followed by a carboard digger with masking tape wrapped around it followed by a cardboard digger with cloth dampened MEK. I inspect the gap with a light and a magnifier. I check the voice coil for any gunk and remove it before using the new diaphragm.

Reconers feel free to add whatever. Reconers should be using gap gauges and the gauges from JBL are expensive.

BTW - On recones always check the VC with an ohm meter before doing anything. I did a beautiful recone job about 30 years ago on a 2121A that had an open VC right out of the box. I naively believed JBL never made mistakes.