The COMBINE4 IEM transmitter combiner from Audio-Technica brings together up to four in-ear monitor transmitter signals into a single transmitting antenna. The IEM transmitter combination is important for multi-channel systems to help minimize intermodulation products arising from multiple adjacent transmitters interfering with one another.

The COMBINE4 works with any brand of IEM and any type of directional antenna operating in the 470-960 MHz range. It's equipped with four BNC transmitter inputs, front-panel LED signal indicators for each input and four DC output jacks that supply power to connected IEM transmitters. Includes one AC cable, four DC cables, and four BNC jumpers.