There is some scientific merit to solid wire, especially in low voltage hook-up wire as discoveries such as "skin effect" and things of that nature are becoming better understood. I believe most hifi manufacturers use solid hook-up wire..perhaps not because of the sound of it, but because it is easy to form, easy to solder and inexpensive to use. I personally have wondered about time alignment of stranded versus solid, but that is only a theory in my mind and I wonder if there is, or ever will be any solid proof of such an effect and if it is audible. In your speaker project, I see the solid wire as a bother more than a benefit, wondering if the wire will come into contact with the cabinet/components and start vibrating them as solid wire acts somewhat like a spring. Stranded wire just kind of hangs there. Of course it's always best to use good wire management practices in these regards. Twisting the wire will help with shielding which really shouldn't be a problem in this application, but it will increase the capacitance of the wires which is generally thought of as bad.
As far as using solid wire for speaker cable.....why? I really see no benefit here and I see the potential for problems with bending the wire, clamping it in a binding post, junk like that. Magnetic wire is really not UL listed for uses like speaker wire. It's used for stuff like motor windings.
Wayner
