The RDL RU-MX4 is a four-channel audio mixer with XLR mic inputs and RCA line inputs. It provides 24V phantom power on a per-channel basis for microphones that require it. Also on hand is a switchable compressor/limiter to keep levels from peaking, if need be. This mixer is useful for combining balanced mic and/or unbalanced line inputs into a single output. The RU-MX4 is suitable for small sound reinforcement, public address systems, or mixer expansion applications.
You'll note that for outputs, you have the options of an unbalanced RCA and a balanced XLR out. The XLR output itself is switchable between mic or line level. While you can only use one input configuration at a time (either XLR or RCA), you can use both outputs simultaneously.
Levels can be adjusted on the front panel, which leaves you enough space to label each input. Each input sports a dual-LED VU meter following standard VU ballistics, with green indicating signal and red to indicate when you go over the correct operating level. The output is displayed on an LED string VU meter. Please note, you must purchase the corresponding PS-24AS power supply separately.