Rack-mount IEM transmitters, the send side of a wireless monitoring system, taking a mix from the console and putting it on air to bodypack receivers. Options include Shure’s PSM 300 P3T and PSM 900 P9T in several band variants, plus Sennheiser’s XSW IEM SR, the SR IEM G4 in GB band and the twin-channel SR2050, which runs two independent mixes from a single unit.

Band matching is non-negotiable: the transmitter’s band code must match the receivers it will feed, so check the letters in brackets against your existing packs before ordering. Channel count is the next decision. A dual or twin transmitter such as the P3T or SR2050 handles two mono mixes or feeds multiple packs on a shared mix, which keeps rack space and RF channel count down on smaller gigs. Once several transmitters share one rack, plan for an antenna combiner rather than a forest of rear-panel aerials, as co-located transmit antennas generate intermodulation that eats your usable frequencies.

The matching combiners and antennas are in the distribution category, and we can advise on frequency planning for multi-channel IEM racks before you buy.