Sennheiser AC 3200-II Antenna Combiner

The AC 3200-II is the box that makes a full rack of IEM transmitters share antennas without tearing each other apart. Its job is straightforward on paper — take up to eight transmitter outputs, combine them onto a single antenna feed — but the engineering behind that is anything but simple. Active combining at this density means the unit is doing real work to keep intermodulation products suppressed, and Sennheiser has built the II revision around the headroom requirements of arena-scale RF environments where cheaper passive splitters or lower-grade combiners introduce noise floors that eat into your link budget before the signal even reaches the stage.

One rack unit, 380mm deep, drawing up to 35 watts — this thing is not subtle in the rack, and at 5kg it will remind you it exists when you're rolling cases. The cascade port architecture is the practical headline: two AC 3200-IIs chained together give you a 16-transmitter system on a single antenna pair, which covers most touring IEM rigs without a second thought. That single BNC antenna output means your antenna placement decisions are made once, at the combiner, and every transmitter in the rack inherits the result — so getting good antennas on good cable with proper gain staging upstream of this box matters enormously.

If you're running six or more IEM transmitters on a serious touring or broadcast rig and you're already invested in Sennheiser's 2000 or 9000 series transmitters, this is the expected choice and the price reflects that pedigree. If you're running four channels at a regional theater or a club residency, the cost is hard to justify and a smaller combiner will serve you. This is also not the box for mixed-manufacturer rigs where you're combining Shure and Sennheiser transmitters — the RF impedance and power levels need to be matched, and you should treat this as a Sennheiser ecosystem component.