What is it? A 4-channel, field production audio mixer. DetailsHoused in a compact, lightweight enclosure, with controls on the front, sides and bottom panels, the X4 is a low-noise design offering four balanced microphone inputs each with a front-panel rotary level control. Also on the front panel is a master fader associated with the left/right line ouputs (switchable to mic level) and a 400Hz reference tone button, to aid setting up. The large left and right meters may be switched between VU and PPM functions and include momentary push buttons which illuminate the scales for 12 seconds. The design also features switchable 3-way low-cut filters (20Hz, 100Hz and 140Hz at 12dB per octave), a switchable limiter, headphone monitoring of left, right or stereo signals and a low-noise slate microphone (routed to left and right outputs). A mixer mode function allows channels 1 and 2 to be ganged for full stereo operation using channel 1 fader with channel 2 fader acting as a balance control. The mixer is powered from eight AA batteries or externally from a DC source of 9V – 18V via a side panel connector. A battery test switch displays battery voltage via the right-hand VU meter. All input connections and mic/line outputs are via XLR sockets, situated on the left and right side panels, together with the pan control and limiter switch, etc. Most of the input and attenuator switching is carried out using recessed sliders on the bottom panel.