Need help with covering for Dueland speaker wire

Thanks for the reply, my friends.  The PVC option occurred to me, but at the ends of it, the wire is still exposed.  I need a sheath of plastic to encompass the wire totally under its exposure in the crawl space.  I currently have Supra Ply 3.4 cabling, which is also tinned copper cable, so maybe I am contemplating a sideways move, sonically.  I love the sound of the Supra wire so I would be happy to be dissuaded of this upgrade notion.  Thanks/

Well this PVC has all sorts of accessories, so you could run it all the way into your home to an outlet box. 

I don’t understand why PVC could not be adapted to work for you whitestix?
There are more expensive options available that one would run AC wiring in underground however it would be significantly more expensive and harder to work with.

Here is the problem. This wire is made with an all natural oil and cotton insulation for a reason. It is because it sounds best. It gives an essentially air dielectric which you want. Any unnatural PVC, Teflon etc... covering will indeed change the sound of this wire.
It will both dull it and take away some of its liveliness.

Secondly, I assume by running the cables under the house you may have lengths of over 15 feet. Most likely approaching 15 - 20 feet...correct? If so, 12 gauge is not thick enough and you will lose fidelity, never mind 16ga. 12 gauge is the thickest Duelund makes.

I think you have two options.

1) purchase Western Electric 10 gauge wire for far less money as it is made in same manner as the Duelund. Duelund used this wire to design theirs. One of the big differences is the WE wire has a thin waterproof covering over the stranded and tinned wires....right under the cotton. It sounds wonderful. I use it under my home so the cable does not run in front of a fireplace. Yes it is a tad more mellow and warm than the Duelund due to this additional waterproof layer of insulation. You can also run this wire through a wide 3-4 inch flexible conduit. Keep it off the water and up against the floor. 

2) if your runs are under say 15 feet you could use a wide diameter flexible conduit to run the 12 gauge Duelund wire through. Do not use small tighter fitting pvc tubing etc,...it will harm the sound. Will a 3-4 inch diameter flexible tubing still impact the sound? I think it may, but its impact would be less than the thicker and smaller diameter pvc type stuff. The wider the better. Keep it off the ground and up on the floor.  

@bacobits1  hits the nail on the head - Don't do this.
Even in conduit, the temperature/humidity changes in a crawl space will result in condensation that will dampen your cotton dielectric.  If you cannot keep the wire "in the house" I would look for something other than Duelund.

@grannyring  made a good suggestion with the WE wire, that has a rubber covering under the cotton and that comes in 10 ga, which would be better for your application.

You might also look into Supra, that offers tin-coated copper wires in a variety of gauges and that come in a "heat and aging resistant PVC jacket." 

Whichever option you choose, I would strongly recommend running PVC conduit, which will help with humidity/moisture issues, keep rodents away from the wires, and which will make it easier to change cables if you ever want to.