If you experience "scratchy" sound or dropouts when turning the knob, use a specialized contact cleaner (like DeoxIT) on the internal level pad contacts. Capacitor Aging:
Limits the mid-range driver (like the JBL 375/2440) so that it rolls off above 7,000 Hz using an inductor in series.
is a classic frequency dividing network (crossover) primarily used to integrate high-frequency "ring radiator" tweeters like the