I have two similar pairs of JBLS 1959s (my fathers) and 1964 bought in mint cond for $400 one is the 15 inch Mid Woofer the 64s have the 12 inch (D131). I want to upgrade the crossovers who did the work and what do you think did the most good.The sensitivity easily equals my Klipsch Heresys and approaches my Las Scalas (Yes I own a lot of speakers) I also have cheap but Gold series Tannoys, VSA VR2s and Focal Electras etc. . You can drive the Klipsch with a fraction of a watt but be aware that a lot of that volume comes from those powerful squawkers. You’ll want more power to drive the woofer to the same levels -really. Your new crossovers may take care of that