Need help with covering for Dueland speaker wire

You could do thin wall PVC pipe. Easy to install, and will make it easy to change them later. Perfectly fine for Class 2. 

I sure wouldn't do that.
The main or one of the ideas is it's natural cotton diaelectric.
Go with a different cable is my advice.

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.

@grannyring..............

I have 22 foot speaker cables that go under my floor to the speakers across the living room.  The cables are 12 gauge and I was told by the manufacturer of the cables (Groneberg) , the manufacturer of the amp (McIntosh) and the speaker manufacturer (Golden Ear) that 12 gauge is overkill and would support up to 70 feet without any loss.

Well we need more info to be sure it will “work”. Work is a far cry from ideal however.

22 feet may be safe depending on your amp and speaker impedance. But 50 - 70 feet.... no way. The OP is using 16, not 12. 

You will hear a definite loss of signal fidelity with 16 gauge runs of 25-70 feet on a 4 ohm speaker. You just will.

Like most things Audio we read and hear conflicting stuff. All amps sound the same, 100 foot runs of 14 gauge speaker wire is fine .,, etc...

My ears and experience tell me not to use 16 gauge for runs of 20 feet and over. 12 gauge may be fine if your speaker is an easy load. 10 gauge is a better bet.

Here is a decent article. The writer also uses 10 gauge.  The issue is why go up against a spec that is at best is debatable? If The speaker’s impedance load goes below 4 ohms at any point, and many do, then the distances listed are certainly too liberal.  

https://www.audioholics.com/audio-video-cables/speaker-cable-gauge

Thanks for the responses ... you wisely waved me off the idea as I am too inept/lazy to run the PVC under my house.  I failed to mention that I currently use Supra Ply 3.4 wire under the house and am going to stick with it.  I prefer the Ply 3.4 to my former Mogami 3403 wire by a fair margin.    

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."

mitch2 beat me to it. Supra is constructed in a similar way to what you want and is made for walls, under floors, etc. That, and I see you already use it and it does meet all the requirements you need, not to mention, all the codes.

All the best,
Nonoise

Nonoise,
Thanks for contributing.  I thought the Supra wire I used under the house for my Spatial Audio speakers was a noticeable upgrade from the Mogami cable I had previously.  I replaced the same Mogami cable in my bedroom system with Western Electric 16ga wire and it was an delightful improvement.  I think the Ply 3.4 wire is pretty revealing relative to its cost so I am gonna forego the contemplated move.  Thanks to all for saving me some dough and some headaches.  Cheers, Mark