Eddy Current

Eddy current reduction, importance to audio cable design

When an audio signal flows through wire, the magnetic fields associated with the signal, are shorted or interrupted by the conductive material. The result of this action is the generation of an opposing field phenomenon called eddy currents. Eddy currents then collapse back upon the conductor, generating a time delayed signal, a form of distortion. The period of the delayed collapse is based upon eddy current resistance, that is directly associated with the strength and speed of the signal and the mass of the conductor.

To illustrate this, we pass a magnet whose fields represent audio signal fields, through a copper tube that is representing the conductor for the audio signal. What you see is the interaction of the magnet fields with the copper. The magnetic fields generate a current in the copper in direct proportion to the field’s speed, strength and the resistance of the copper. Changing any one of these parameters effects the outcome. This induced current in turn generates its own opposing magnetic field that resists motion of the magnet. This is known as eddy current resistance. 

To demonstrate the affect of increased eddy-current resistance, we pass the same magnet through a thicker copper tube. The greater the mass of an electrical conductor, the greater the eddy current resistance. This means that the collapse of the opposing eddy current field, happens at an even later time, resulting in a greater smear affect of the audio signal. This is why, the timing and coherence of an audio signal is directly affected by the conductive mass of the cable. The thicker the cable, the greater the eddy current resistance and induced distortion.

As in any resistance, the induced eddy current energy is converted into heat and is lost forever - it cannot be recovered. Lower mass cables and cable connectors minimize eddy current resistance. As such, Audience believes this to be as important as any other design parameter for optimal performance of audio signal cables.


Please see YouTube video