A couple things. First, since it's presumably something like zipcord, the two conductors run in parallel and are closely spaced. Because of this the speaker current will tend to cancel and the coupling between adjacent runs of wire will be minimal. Coiling the excess will have no marked effect.

Second, the delay introduced by an additional 4 feet of wire will be about the same as moving the speaker back by 0.000,001 inches. Light travels about 11.8 inches per nanosecond; the velocity in cable is about 1/3 that, so we have about 12 nanoseconds delay. With sound at 1 foot per millisecond we have about 12/1,000,000ths of a foot or about 1 one-millionth of an inch. 20 kHz is about a half inch wavelength; the delay is negligible unless you've positioned your speakers with this accuracy. :-)