The Principle And Function of Golden Eagle Inductance Coils in Crossovers

The Principle and Function of Golden Eagle Inductance Coils in Crossovers

From a working principle perspective, a crossover is essentially a filter network composed of capacitors and inductance coils. The treble channel allows only high-frequency signals to pass through while blocking low-frequency signals; the bass channel does the opposite, allowing only low-frequency signals to pass through while blocking high-frequency signals; the midrange channel acts as a band-pass filter, allowing only frequencies between two crossover points (one low and one high) to pass through, while both high-frequency and low-frequency components are blocked.

Although this may seem simple, in practical crossover applications, to balance the flexibility differences between upper and lower sound units, attenuation resistors of varying sizes or impedance compensation networks composed of resistors and capacitors must be added according to different conditions. Naturally, different designs and manufacturing processes make this seemingly unremarkable component—the crossover—produce varying effects in speakers. These details are precisely what all Hi-Fi equipment must pursue, and they also represent the fundamental difference between Hi-Fi and ordinary civilian equipment. 

For inductance coils used in crossovers, a large DC resistance not only increases rated power loss but also reduces the electromagnetic damping of the speaker, deteriorating transient characteristics. Therefore, the DC resistance of inductance coils must be extremely low. Especially when used in series with speakers, the DC resistance of the inductance coil should be at least less than 1/10 of the speaker's impedance. To meet this requirement, hollow, large-diameter coils with iron cores are typically used. However, because the magnetic permeability of iron cores changes with input and has a low magnetic saturation point, which easily causes distortion, the properties and shape of materials must be carefully studied. Ferrites or silicon steel sheets are mainly used.

In winding materials, copper wires are mostly used as conductors, and different names are given according to the types of insulation layers on the copper wires. For coils used in crossovers, enameled wires or polyethylene-insulated wires are mostly used, as they have excellent insulation capabilities and anti-interference properties. In places requiring heat resistance, polyethylene wires or polytetrafluoroethylene (PTFE) wires can be used.

Dongguan Golden Eagle Electronics has been engaged in coil production and R&D for more than 20 years, accumulating rich experience in the coil industry.