Do you know the difference between a hollow inductor and a solid inductor? In the case of the same number of turns and volume, the "inductive reactance" value of the hollow inductor is much lower than the solid inductor; this has led to the hollow inductor being more suitable for a wide range of frequencies. The impedance allows most audio or audio to pass, while the solid sense impedance is only selective, allowing only a portion to pass. Generally speaking, the use of these two types of inductive reactance is mainly because the needs of audio and audio are taken into consideration to achieve the purpose of frequency division output.
