Steven, the bypass high-quality cap is connected in paralell with the larger, less expensive cap.
Their values add. In the example above, 4.5 uF + .5 uF = 5 uF. The combo replaces a 5 uF cap in the crossover.
Their values add. In the example above, 4.5 uF + .5 uF = 5 uF. The combo replaces a 5 uF cap in the crossover.