Shielding prevents interference from entering the audio signal conductors and producing undesirable noise. There are three basic types of shielding -- braided, wrapped and foil. Foil shielding provides the best insulation, but has very little flexibility and degrades easily. Foil-shielded cables are best for fixed installations. Wrapped shielding provides the highest flexibility, but can open up over time, which can cause noise to enter the audio signal. Braided shielding offers a combination of flexibility and durability, making it a common choice for microphone and line level audio cables.
Audio cables can either be balanced or unbalanced. Balanced cables use two signal conductors plus a ground and are most common in professional audio gear. The most common examples of balanced cables are XLR and quarter-inch TRS. Balanced cables use the two conductors to cancel unwanted noise picked up in the cable. Unbalanced cables have a single audio connector plus a ground connection and are used for purposes like instrument cables and RCA cables.
To connect your connector to your audio cable, you need to solder. Strip the cable to expose the wires and have the connectors ready before you start the soldering process. When soldering, heat up the contacts and apply a little solder before you connect the wire. This will prevent a cold solder, which can result in a weak contact. Use only enough solder to connect the wire to the contact. Be sure not to strip too much of the wire. If the bare wires touch near the connectors, it will short out your cable. For an XLR connection, the shielding connects to pin one for the ground, the positive wire connects to pin two and the negative wire connects to pin three. For a TRS cable, the positive wire connects to the tip, the negative wire connects to the ring and the ground connects to the sleeve.
Once you solder your connections, test your cables before you assemble the connector's casing. You can use a cable tester or a multimeter to test the cables. If you are using a multimeter, set it to the continuity setting. Touch one probe to the same contact point on each end of the cable -- for example, pin one on the male side of an XLR and pin one on the female side. Each connection should give you a continuity reading. If a connection does not give you a proper reading, check your solder points to make sure your connections are good.