The Livewire SPDI Passive is a compact direct interface designed to convert instrument-level or line-level signals for use in professional audio systems without requiring external power. Its passive circuitry supports dependable signal balancing and impedance matching, making it suitable for connecting instruments, playback devices, or submixes to mixers and audio interfaces. The unit is designed to preserve signal integrity while minimizing noise and unwanted interference in typical live sound and studio environments. Housed in a durable enclosure, the Livewire SPDI Passive is commonly used in portable rigs, rehearsal spaces, and installed systems where simplicity, consistency, and reliable signal routing are priorities.