Andy - my first-choice idea for multiple runs is to twist the bunch (2 or 3) 18 ga varnished coil wires having essentially no dialectric. That wire-twine is insulated with a cotton sleeve (very low dielectric absorption) if physically necessary - and/or physically kept from contacting its opposite polarity mate or other conductor. Driver runs will require spacers so that the ± twine-pair can be twisted to reduce capacitance. I am looking at teflon donuts for that purpose.
Much of the insulation requirement for speaker cables and interconnects is due to handling, being stepped on and so forth. Inside a speaker cabinet is a safer, more predictable environment.
Much of the insulation requirement for speaker cables and interconnects is due to handling, being stepped on and so forth. Inside a speaker cabinet is a safer, more predictable environment.