The 4 Way Active Crossover is special 

4 Way Active Crossover Special, Comrades
Info Price 330 thousand, not yet admin fee, if you have entered Olshop there are admin and service fees
Special Chat WA 0882-3115-8897 (does not accept complicated people)
the purchase link is below
Lazada (COD) s.lazada.co.id...
Tokopedia tokopedia.link...
Bukalapak www.bukalapak....
Shopee shopee.co.id/p...
It's nothing special, starting from the super nice Fiber Double Layer PCB, printed directly onto the JLCPCB
Taiwanese Full Metal Film Resistor Thick copper feet, MKM Capacitor Red and Mylar blue
Elco Jackcon Taiwan, full sockets from input to output and ICs all use sockets, so it doesn't damage the PCB if there is a component change, potentiometers Alpha Plus and AM Taiwan are of good quality, not easy to get dirty
IC TL074 & NE5532 Original Texas Instruments
there is already a phase inverter
Input Output Balance to minimize Noise or other disturbances
System Filter SV or state variable with 24dB/octave slobe, which can be changed to change the frequency response by rotating the quad frequency potentiometer
frequency response 20-20khz, sometimes it can be more or less