Using solid copper Door Bell wire as speaker wire.

Audiolabyrinth, just because some manufacturer pastes their logo on it and puts it in a fancy bag/box/aluminum case, doesn't make it particularly better. Cables consist of copper (or silver) wire, dielectric material, geometry, damping materials, shielding (or not) and connectors. I understand there is research behind most of the top cables, but there is also a lot of marketing spin and fairy dust. You don't have to pay a lot of money to get good sound. I have heard, many upper range cables from manufacturers like Purist, Cardas, Audioquest, AZ, and others and, mostly, I prefer cables I have made myself. If the OP’s doorbell or thermostat wire is CDA 101 OHFC copper, and the dielectric is PE, this is about as good as is being used by many of the top cable makers. That it is solid core gives it an additional boost in my opinion. You shouldn't make the guy feel "unworthy" just because he isn't spending a bundle on cables. We will never agree because IMO the impact of a cable will never equal the impact of a component on how a system sounds.

People cannot hear the difference between cables for many reasons. It could be their system that is not resolving enough, could be their hearing instrument or just negative placebo effect since they often strongly believe, that cables cannot sound different. Often they feel defensive about inability to hear the difference (if I cannot hear, nobody can) and post questions about lamp cords or thermostat wires to find confirmation from the other people. Since wire is inexpensive just try it - If it sounds good to you then use the cheapest one, even if it is barb wire (be careful). No right or wrong here.

So important you need 2 threads??

Two threads...better than one? 👀

When the efficacy of expensive cables or tweaks is challenged by someone who might be considered to be a skeptic about such things, especially where the claimed efficacy seems unexplainable or quantitatively counter-intuitive on the basis of generally recognized science, it is common for responses to be along the lines of "if you haven't tried it, you can't have an opinion."

It seems to me that such a response would be no less applicable to those who would challenge the efficacy of specific inexpensive or DIY cables such as those being discussed here, theoretical considerations about metal purity and other factors notwithstanding.

Regards,
-- Al