Seismic Audio SA-RMSS-24 Mic Splitter

The SA-RMSS-24 sits at the practical center of Seismic Audio's rack-mount splitter line — 24 channels of transformer-isolated splitting in a 4U chassis for $849. Its job is straightforward and non-negotiable: take every mic and line input from the stage and give FOH and monitors their own independent, isolated feed of each signal. The transformer isolation is what separates this from a passive Y-split — each isolated output breaks the ground path between consoles, which means a ground loop on the FOH side stays on the FOH side and doesn't crawl into the monitor world.

In practice, 24 channels lands you comfortably in a six- or seven-piece band with horns, a multi-keys rig with several sources, or any setup where a 16-channel unit would force you to choose which inputs skip the split. The chassis draws zero power, so it adds nothing to your power budget and can sit on a non-switched outlet without concern. At 7.7 kg and 200 mm deep it's dense but not unreasonable — a standard 12U shelfed rack handles it without drama. The direct outputs pass signal without touching the transformers, so one console sees the unaltered feed while the isolated outputs serve the other.

This unit is the right call for a monitor engineer who has outgrown 16 channels but doesn't need the 32-channel headroom — or the freight weight — of a festival-grade box. If your input count reliably sits between 17 and 24, this is the cleanest fit. If you're regularly at 25 or above, step up; half-measures with splitter capacity tend to surface at the worst moment. Engineers running fully digital splits via a stagebox who only occasionally go analog should think carefully about whether a passive transformer splitter at any channel count is the right tool, or whether a smaller utility splitter handles the edge cases better.