Using instrument cables instead of speaker cables

[Ayek]

A few years back I was talking to a home audio installer who said he used cat5e UTP in his home for speaker wiring. He'd use separate the cores into whites and coloureds, didn't mention any braiding or removing the sheath. Seems like it'd be ok power handling wise, as it's 4 0.5mm2 strands. Wouldn't want to stress it too much if it solid core, mind you.
For instrument cabling, it'd be interesting to see if you could get away with using twisted pairs instead of screened cable.

[Hemisaurus]

I hadn't read the linked article when I first replied, but I'll point out a few flaws.

The author talks about twisted pairs getting the same amount of noise introduced into each wire, and thus cancelling out, yes, but only in a balanced audio circuit, where one side of the signal is inverted and fed into the other, otherwise you just have noise on both lines.

Likewise he talks about the good dielectric properties of the insulation, is he implying this gives us a high capacitance? There's no imedance spec. just a plain resistive measurement, all those different cores wound together could have a significant amount of capacitance, the kind that makes tube amps go boom.

If you do try this out, I'd suggest trying it on something modern, and solid state, or attempting to measure the capacitance of it, and compare that to a regular cable before use.