Using solid copper Door Bell wire as speaker wire.

If a system or the owner of that system cannot hear a difference between solid core and stranded wires,then spending big bucks on expensive name brand wires is a waste of money.

Cheap bell wire used as speaker wire should sound different(less boomy)than cheap stranded wire.

All amps do not sound the same ,all wire does not sound the same.
All tubes do not sound the same, all fuses do not sound the same.
And on and on, as it should be.

If everything sounds the same, then stick with what you have and enjoy the music.

If a poor recording sounds the same as an expensive 45rpm reissue, then stick with the system you have.

If cd's sound as good as vinyl, stick with what you have.

If everything sounds the same and it's pleasing to your ears, then stick with what you have and invest no more money.

If that 1970's solid state receiver sounds better than todays best, then stick with it,and by all means use your trusty 18 gauge lamp cord for those press-wood multi drivers.

If you rely on the specs then don't even buy an audio system. Just read the sheet music.

Remember your ears are easily fooled,and snake oil is everywhere.

Still difficult to believe that different amps all sound the same if level matched. If that is true then we should all be using very inexpensive amps. You did find cables made a difference. I don't think that argues for the use of very inexpensive cables, however it wasn't clear that solid copper wire would be a bad idea.

tried it...caused too much ringing

My two cents worth is a conductor for speaker cable applications should be no smaller than 32 gauge, lol, and having enough to become 4 gauge or bigger with each negative run and positive run, and of course reasonable dielectrics to accommodate such a cable not be polluted by the sound of a lessor dielectric that most audiophile's do not know they hear!

Actually cloth/rubber covered copper house wiring from the 1940s sounds even better. :)