The Barbettas are not like passive speakers. They have balanced inputs, or you can also use unbalanced cables, but they should definitely NOT be speaker cables. Guitar or mic cables are fine. I think they sound a little better with balanced cables, and Tony Barbetta agrees.
Sometimes I go directly from my keyboard outputs to the Barbettas. For this I use unbalanced guitar cables. Sometimes I go from the kb to the mixer and then to the Barbettas. For this I use balanced XLR to balanced TRS cables.
You CAN use the XLR "mic" input on the Barbettas, but be careful because it is hot and would make it possible to overdrive the amps in the Barbettas.
DonM