Thanks, Tom Thiel, for your experienced and insightful response.
I have heard the sounds of Barkhausen noise generated by the rapid change in magnetic fields. I know this firsthand in my use and experiments with magnetic materials, varying field strength and geometric shapes within prototypes of my products for acoustic instruments.
I will take what I learned in close quarters about my devices for acoustic instruments and expand into this speaker project. Hope it is no deeper than a rabbit hole and less than a Minute Man Silo. Still learning after all these years. TomD