To properly wire a balanced to balanced cable using 4-conductor Starquad and maximise noise rejection opposing conductors are terminated together into an XLR-3 connector or terminal block.
In this example where the BBC standard colour code is used Blue & Red (+ Positive Phase) are wired together forming one half of the balanced pair and Green & White (- Negative Phase) are wired together forming the other half. Some starquad cables use two white conductors for the positive and two blue cores for the negative.
Starquad cables are four conductor cables which are all insulated and twisted together on a common axis. This “quad” construction or double balanced pairing reduces the chances of electromagnetically induced noise.
As the diagram below shows , the four conductors are arranged in a cross formation ,the conductors opposites are wired together in parallel to form a single balanced pair .The signals are sent out of phase with one another and then returned at the destination. The interference collected along the cable length is also then inverted, so put out of phase and made silent.
The outer screen helps to prevent electrostatic interference from reaching the signal cores .