Workflow · Intermediate · 6 min read

MOTU M4, M6 or UltraLite-mk5: Which Interface Runs Your Playback Rig?

Outputs, preamps, power and rack mounting for the three MOTU interfaces bands put in playback racks for tracks, click and keys.

Get the short answer Plan it in IEM Rig

IEM Rig GuidesPublished Nov 5, 2026Checked against 5 source documents

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Before you start

A playback interface is judged by its outputs first: how many separate feeds of tracks, click and cues it can send to front of house and to the monitor mix. Preamps, power and rack mounting decide the rest.

The short answer

MOTU M4: four balanced line outputs from a bus-powered desktop box. Enough for stereo tracks plus click and one cue pair.
MOTU M6: the same four line outputs with four mic preamps instead of two and a second headphone output.
MOTU UltraLite-mk5: ten balanced line outputs, ADAT expansion and an onboard monitor mixer. The one to rack when tracks are split into stems.

Side by side

Figure 1. The three interfaces this guide compares. The M4 and M6 sit on a desk, the UltraLite-mk5 is half-rack width.

M4

Two XLR/TRS combo inputs with independent preamp gain and individually switched 48V phantom, four balanced DC-coupled quarter-inch line outputs (mirrored on four RCA jacks), one headphone output, MIDI in and out, and USB bus power. See the M4 page.

M6

Four XLR/TRS combo inputs for mic, line or Hi-Z guitar, each with its own 48V; two more balanced line inputs; four balanced DC-coupled line outputs; two headphone outputs with independent volume; driver loopback; MIDI. It is bus-powered with an optional 15V adapter for running without a computer, and measures 1.8 x 9.21 x 4.75 inches. See the M6 page.

UltraLite-mk5

Two combo mic/line/instrument inputs with individual 48V and up to 74 dB of gain, six balanced line inputs, ten balanced DC-coupled line outputs, a headphone output, eight channels of ADAT optical, S/PDIF and MIDI: 18 inputs and 22 outputs in all. A DSP mixer gives each analog output pair its own monitor mix. It runs from an external 12 to 18V DC supply rather than USB power, and racks with a separately sold kit. See the UltraLite-mk5 page.

Preamps

Explore in 3DMOTU M6Four combo inputs and four line outputs.Gear page ›

Preamp count: M4, 2. M6, 4. UltraLite-mk5, 2. All on combo jacks, so a line source plugged in there uses up that preamp.
Gain range: M4 and M6, 0 to +60 dB on the mic input (0 to +57 dB on the quarter-inch side of the combo jack), per MOTU’s M Series user guide. UltraLite-mk5, up to +74 dB; MOTU doesn’t publish its minimum.
Phantom power: 48V switched per input on all three.
Gain control: an analog gain knob per input on the M4 and M6. The UltraLite-mk5 sets gain digitally, from two front-panel encoders or the CueMix 5 app, and adds a switchable -20 dB pad per input.
Noise: MOTU rates the M-series mic inputs at -129 dBu EIN at maximum gain (150 ohm source, A-weighted).
Rig impact: a playback rig rarely needs more than a talkback mic and a keyboard input. If it does, the UltraLite-mk5’s ADAT input takes an eight-preamp expander. See how many preamps your rig needs.

Counting playback outputs

Rear panel, drawn by IEM Rig

MOTU UltraLite-mk5

Figure 2. The UltraLite-mk5’s rear panel as the planner draws it, where its line outputs for stems, click and cue live.

Stereo tracks to front of house take two outputs, and click to the monitor mix takes one more. Split the tracks into stems (drums, keys, vocals) and each stereo stem adds two. The M4 and M6 stop at four outputs; the UltraLite-mk5’s ten cover five stereo stems, or four plus click and cue. For two interfaces running side by side as a backup, see redundant playback rigs.

Full specs: the M4, M6 and UltraLite-mk5 gear pages.

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Sources

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