Air core inductors provide better functional response loudspeaker crossover circuits because they generally offer lower distortion and a wider frequency response compared to iron core inductors.
Iron core inductors can introduce distortion due to core saturation, hysteresis, and eddy currents, which can affect the audio signal negatively. These effects are particularly noticeable at higher current levels, potentially leading to a less clear and detailed sound.
Air core inductors, being free from these core-related distortions,, are cleaner and more transparent sounding.. They are also more efficient at higher frequencies, making them better suited for wider FR crossover designs.
In essence, the absence of an iron core in air core inductors eliminates the potential for core saturation and other distortion-inducing factors. This provides more accurate and linear reproduction of the audio signal, resulting in a perceived improvement in sound quality.