Polarity of Black/White speaker wire

[mrmudcat]

I would think all black wire is meant for negative in standard wiring so white to positive ....................

[tot_Ou_tard]

I would think all black wire is meant for negative in standard wiring so white to positive ....................

That's what I thought, but after googling about & asking an electrician friend. It seems that either there's no standard or the it's common that black goes to positive & white to ground.

[mrmudcat]

Tot hopefully someone smarter can shed some light on this: