Harmonics are caused by the different modes that any entity vibrates at (physical, electrical, or magnetic). If you strike and object with an impulse a rich ar

Harmonics are caused by the different modes that any entity vibrates at (physical, electrical, or magnetic). If you strike and object with an impulse a rich array of vibrations will occur (think of a gong, a snare, a garage door) all of those modes will be present if you repeatedly strike or oscillate the object.