RDL FP-MX4 – 4-Channel Mic/Line Audio Mixer

What is the RDL FP-MX4?

The RDL FP-MX4 is a 4-channel audio mixer that combines microphone and line-level sources at preset levels in a compact FLAT-PAK module. Each input is switch-selectable for line level, mic level, or mic with 24 V phantom power, and accepts balanced or unbalanced wiring. Simultaneous balanced line and mic-level outputs let the mix feed an amplifier, recorder or another mixer. It is well suited to conference rooms, lecterns and small sound reinforcement systems that need a fixed, installer-set mix.

How does it work?

Each input section provides a detachable terminal block, a source switch (LINE, MIC or MICPH) and a MIC GAIN switch with LOW, MED and HIGH ranges covering 35 dB to 65 dB. Because each channel has its own switches, any combination of four sources can be used at the same time. The mic inputs use RDL's low-noise discrete preamplifier stage for performance usually reserved for studio equipment. Four mixing potentiometers set the level of each input and can be adjusted by screwdriver or by hand, and unused channels can be turned fully off. The output section provides a balanced +4 dBu line output and a balanced -45 dBu mic-level output, and both can be used at once. A dual-LED VU meter simplifies level setting, with the green LED reaching full intensity at +4 dBu and the red LED lighting above that level. Power connects through barrier terminals or a dc jack, and a second dc jack passes power to additional FLAT-PAK modules. The low-profile chassis mounts on rack sides or rack rails with the RDL FP-RRA, and connector placement allows high-density mounting against flat surfaces. RDL recommends the PS-24AS power supply for the USA or the PS-24AX for international installations; the supply is not included.

What are the key features?

• Four mic/line inputs — Each input switches between line, mic, or mic with 24 V phantom, wired balanced or unbalanced.
• Three mic gain ranges — LOW, MED and HIGH ranges span 35 dB to 65 dB to match a wide range of microphones.
• Dual balanced outputs — Line (+4 dBu) and mic (-45 dBu) outputs are available at the same time.
• Low-noise preamps — RDL discrete mic preamplifiers deliver studio-quality noise performance.
• VU output meter — A dual-LED meter with standard VU ballistics makes level setting quick and accurate.
• FLAT-PAK format — The compact module fits confined spaces and shares power with other FLAT-PAK modules.

Where is it typically used?

• Conference room
• Boardroom
• Training room
• House of worship
• Multi-purpose room

Technical Specifications

Frequently Asked Questions