The Sound Devices 633 6-Input Field Production Mixer and Digital Recorder is designed for production audio mixing and recording on set and in the field. The unit is housed in a compact lightweight molded metalized carbon-fiber chassis and features six analog inputs: three XLR microphone preamplifier inputs with selectable phantom power, high-pass filters, input limiters, faders and variable pans, as well as three line-level TA3 (mini-XLR) inputs. The first XLR input can also function as an AES digital input and accept AES3 or AES42 inputs with +10 V phantom power for digital microphones. The two XLR outputs can also be used as four channels of AES output.

All of the unit's inputs can be assigned to the mixer's six output buses: left, right, Aux 1, Aux 2, Aux 3, and Aux 4. Selectable input delay on all six inputs and output bus delay on all six buses makes it easy to correct lip-syncing issues between audio and video. The unit's 1/4" headphone output can be configured with different user-presets and a favorite mode allows for quick source selection when monitoring.