designed according to frequency response and phase measurements.
Getting speakers to
sum properly over the audible range is the primary challenge
because of each driver's inherent mechanical/electrical behavior.
Off the shelf crossovers in consumer audio are rarely correct.
They're not designed for specific drivers or systems of drivers
Components: OFC wire, low-ohm perfect-lay
air-core inductors, polyester or mylar capacitors and non-inductive
Price depends on the inductor values.
The lower the bass-mid crosspoint, the larger and more expensive
the inductors have to be.