Ferrite cores are small semi-magnetic iron pieces encased in a plastic snap enclosure. Designed to fit around power cords and interconnects, they block electromagnetic interference and unwanted high frequency information. Since ferrite shields can often affect these frequencies in the analogue domain, it is usually used for digital and power cables where frequency manipulation is not audible. Ferrite cores have been used for years in the engineering, computing, and electronics industries.
Open the ferrite core by unsnapping the connector latches. The core will open, revealing a concave surface.
Lay the cord into the channel, usually within 2 to 3 inches of the connector. You may have to experiment with the final location depending on the effectiveness of the high frequency abatement.
Loop the cable 1 or 2 more times around and through the core. This helps "lock" the core in place, and may be required in circumstances with severe interference.
Close the core and snap the halves back together.