Wire gauge affects resistance, with lower gauge numbers indicating thicker conductors that can carry audio over longer distances with less signal loss. Longer runs and higher-power or lower-impedance loads generally call for a heavier gauge, while shorter runs may support lighter-gauge underground speaker wire, based on the system’s specifications.

Two-conductor underground speaker wire carries one speaker signal, making it suited to a single speaker or one audio channel per run. Four-conductor wire carries two speaker signals in one jacket, which can help simplify runs for stereo, multi-speaker, or landscape audio installations.

Use direct-burial speaker wire when the cable will be placed directly in soil and the installation calls for a jacket rated for underground use. Use speaker wire in underground conduit when you want an added layer of physical protection, a defined pathway, or easier access for future cable work, and follow local electrical and building codes for the installation.

For underground speaker wires, compare jackets designed for direct burial, such as thermoplastic PVC sheaths that help protect conductors from moisture, along with easy-to-strip or low-friction features that can support installation. Review the applicable listings, such as UL, Class 3, FT4, or CMG, and confirm the cable’s temperature range, including products rated from -20°C to 75°C, against the project requirements.