( “Is there something different in speaker cable copper that is different from regular copper cables? “ )
Yes. How copper is refined and extruded. For a quick overview go here: http://www.outlawaudio.com//products/cables_about.html#
and look at OFC and OCC processes.
( “Also is it okay to use solid wires instead of stranded?” ) Everyday electricians, definitely use smaller multi-stranded wire applications, Vs solid strand, for wires when vibration, or flex is a factor. As Morphsci pointed out in speaker wire, in speaker wire manuf. the flex factor should be accounted for whereas when buying wire at a building supply you should factor this. There are complaints about wire on occasion even when manufactured specifically for speakers or interconnects, (solid or multi-strand) being exceptionally stiff causing difficulties on bends around busy backs of hardware, also the stiffness, weight factor, causing connections to back out or work loose in some applications. How solid strands Vs multi-strand bundles affects resistance, inductance, capacitance, is another world of info. ‘Skin effect’, Dielectrics, winding geomety, un-insulated strand bundles arch effect, electromagnetic’s, and on and on.
( “work with regular electrical wires?” ) Lots of people make, DIY braided multi-strand or a run of solid strand, speaker wire, out of products they get from building /electrical/electronics suppliers.
Do an archive search on sites like this and you find heated debate on whether or not electrons being passed, from point A to B on a wire, can affect sound.
For myself, In the simplest basest terms possible, when I reflect on how electrical impulses are passed through a wood ladder Vs an aluminum one, (basic conductive/insulation principles), I personally assume that the manf. and design of wire, can and will affect how electrons travel, but theres a world of “degree” here.
Mankind is so innovative and fun, personally it wouldn’t surprise me to find “Ionic Cables” listed for sale someday. Little tiny sealed tubing, with wire running through saltwater.
Choice is good!