Why Soft Iron is suitable for preparing pole pieces in earphones as well as loudspeakers instead of steel?

Soft iron is suitable for preparing pole pieces in headphones as well as loudspeakers instead of steel because soft iron materials have high permeability and low coercive force. They are easily magnetized and demagnetized. Examples of soft magnetic material are silica-steel (Fe-97 and Si-3), Sandust (Al-5, Si-10, Fe-85).

Soft iron materials have following characteristics:-

Thin hysteresis loop.

High permeability.

Low coercivity.

High susceptibility.

Low hysteresis loss.

Low eddy current loss.

Whereas materials made up of steel have totally different properties i.e.

High permeability and High hysteresis loss.

Large hysteresis loop.

High coercivity residual magnetism.