Centered at 500Hz to stabilize the mechanical junction between the cone, spider, and voice coil. Crossover Networks

Centered at 22Hz with varying bandwidths (10Hz to 1000Hz) to loosen the spider and surround. Bass/Midrange Cones

This is a technical instrument, not music. Improper use can damage your speakers. Magic CD - JMR Electroacoustique - jm-reynaud.com