The Spirit M12's EQ range is limited, with a mid-frequency range of 250Hz-9kHz, a low shelf at 60Hz, and a high shelf at 16kHz.

Lack of onboard per-channel compression is a noted drawback, with Yamaha, Behringer, and Mackie offering alternatives with this feature in a similar price range.

The M12's AUX outputs are balanced 3-pole jacks, not stereo, allowing for noise reduction when used with TRS connectors, similar to XLR functionality.

The M12's stereo channels lack direct outs, prompting users to utilize AUX sends as a workaround for recording individual stereo tracks.

The M12’s AUX returns allow for stereo effects processing, with RCA jacks controlled by red aux volume knobs, integrating external effects smoothly.

The stereo RCA returns are designed to accommodate mono-to-stereo effects, like reverbs, which output stereo from a mono input, optimizing space by using RCA instead of TRS 1/4”.

The choice of RCA over TRS for stereo returns is influenced by space constraints on the mixer’s compact top panel, especially given the inclusion of four aux sends.

Owners compare the M12 to the Allen & Heath GL2, noting that the GL2 offers EQ down to 30Hz, which some users find more versatile.

Users have noted that the M12 is a budget mixer with concessions, like limited EQ tweaking, but generally decent functionality for its price point.

Some owners use a TS cable partially inserted into the insert jack to record channels, a commonly shared technique for bypassing direct outs.

The M12 is often seen as suitable for basic tracking and mixing, but not ideal for tasks requiring extensive EQ flexibility below 250Hz.

Users can split stereo channels into mono by routing left and right signals to separate AUX sends for individual mono recording.

Aux sends are often utilized for mono-to-stereo effects processing, maintaining the original stereo image of clean signals while integrating stereo spread from effects like reverb or delay.