MOTU M4 Specs: Inputs, Preamps and Sample Rate

The MOTU M4 is a desktop audio interface in the $300 to $700 band, connecting over USB-C with 2 microphone preamps. The M2 with two extra line inputs and two extra outputs, still bus powered, still with the LCD meter.

What is the MOTU M4 good at?

Four outputs and MIDI while staying bus powered, which is rare.

In practical terms, 2 microphone preamps is the number that decides what you can record at once, and it is the number most worth reading carefully. Manufacturers routinely advertise a total input count that includes line inputs you cannot plug a microphone into and digital channels you cannot use without buying another box. The specification table above counts physical analogue jacks and preamps separately for exactly that reason.

It runs on bus power, so a laptop and a cable is the whole rig. MIDI in and out are present, so a hardware synth or an older controller connects directly.

What is it not good at?

Only two of the four inputs have microphone preamps.

Every interface trades something. The useful question is not whether a box has a weakness but whether its weakness lands on something you will actually do. A missing MIDI port is irrelevant if you never touch hardware synths and a permanent annoyance if you do. A 96 kHz ceiling is a non-issue for almost every music recording and a hard stop for a small number of specialist workflows. Match the limitation to your own work rather than to a specification comparison.

What else has 2 microphone preamps?

These are the direct alternatives by the number that matters most, rather than by price. Two interfaces with the same preamp count are solving the same problem, and the differences between them are in the driver, the gain available and what else is on the back panel.

Is there a cheaper interface with the same preamp count?

Yes, and it is worth knowing before you spend. These sit in a lower price band with at least as many microphone preamps. What you give up moving down is usually driver maturity, gain headroom, metering or build, and none of those show up in a channel count comparison.

• Focusrite Scarlett 2i2 (4th Gen), 2 preamps, $150 to $300. The most common interface in home studios, and the correct default for one voice plus one instrument.
• Universal Audio Volt 2, 2 preamps, $150 to $300. Two channels with a switchable vintage preamp voicing, aimed at people who want colour on the way in.
• Audient EVO 4, 2 preamps, under $150. Two preamps and a Smartgain button that sets your levels for you, under the price of most single-channel boxes.

How much latency will it give you?

The interface itself contributes a fixed overhead, and the buffer setting contributes the rest. Latency in milliseconds is buffer samples / sample rate x 1000, so a 128 sample buffer at 44.1 kHz is 2.90 ms one way and about 5.80 ms round trip before the hardware is counted. A USB-C interface typically adds another 2 to 6 ms of converter and driver delay on top, which is the part that varies between manufacturers at the same buffer setting.

Work out your own figure with the latency buffer calculator, and check the full conversion grid on the sample rate and latency chart. If you are choosing between this and a Thunderbolt unit, the USB versus Thunderbolt comparison covers where the difference is real and where it is marketing.

Will it drive the microphone you want?

Gain is the specification that decides this and it is not on most product pages. A large diaphragm condenser needs roughly 40 dB for a sung vocal at six inches, which every interface here supplies comfortably. A low-output dynamic like the Shure SM7B needs closer to 60 dB, and that is where budget preamps run out and you start hearing hiss before you reach a usable level.

Check your own combination against the gain staging calculator before ordering either the interface or the microphone. If the figure comes up short, an inline booster adds about 25 dB of clean gain at the microphone end for far less than an interface upgrade.

Other MOTU interfaces

• MOTU M2, 2 preamps, 2 in and 2 out, $150 to $300

Where this fits in a whole setup

An interface is one line in a chain, and it is rarely the line that limits a home recording. See what a complete build looks like at three budgets on the setups hub, compare interfaces against each other in the interface roundup, or work through the decision properly in how to choose an audio interface. The full specification database lets you filter by preamp count directly.