Its a wooden rack but the speaker stands are metal. It shouldn't touch anything metal?
Yes, Bundee. The metal legs will increase the inductance if the cable is wrapped around them, or even close.
For example, at 1khz, if the speaker cable's inductance rises by only 10uh (10 microhenries), the reactance will increase by .063 ohms, at 5khz the inductance increases by .314 ohms, at 10khz .628 ohms, and at 20khz by 1.25 ohms.
Pretty appreciable increase.