An audio interface sits between a microphone and your computer. This guide explains what it does, which specifications to compare and which questions to settle before you buy, using manufacturer and software documentation read in November 2026. It names three current models as examples of how the numbers differ, and it does not rank them. For the full gear picture, see our streaming setup guide. The images on this page are illustrations, not product photos and not Gimaxo tests.

An earlier version of this page gave price bands, a list of “best” models and several claims about motherboard audio and latency. We removed them: prices change, and we found no source for the rest.

What an interface does

RØDE, a microphone maker, says every microphone setup needs three components, and that in a USB microphone they are integrated in one device. An XLR microphone is different: RØDE says it needs an external audio interface to connect to a computer. The interface supplies the preamp that raises the microphone’s weak signal and the converter that turns it into digital audio.

Questions to settle before comparing models

How many microphones will you connect? Interfaces differ in how many microphone inputs they have. Focusrite lists one microphone preamp on the Scarlett Solo (4th Gen) and two on the Scarlett 2i2 (4th Gen). MOTU lists two combo inputs, each taking a microphone or an instrument, on the M2. If you may add a guest later, count the inputs now.

Does your microphone need phantom power? Shure says condenser microphones must be powered, either by batteries or by phantom power, which is supplied through the microphone cable. Focusrite lists phantom power on both Scarlett models, and MOTU lists 48V phantom power on the M2. A dynamic microphone does not need it, but check the microphone’s own documentation.

Illustration of a generic audio interface, not a photo of a specific model and not a Gimaxo test.

Does the interface give enough gain for your microphone? Focusrite lists a microphone gain range of 57 dB for the Solo and 69 dB for the 2i2. A quiet microphone needs more gain than a loud one. Compare the figure with the output level in your microphone’s specification sheet. We did not find a manufacturer statement we could use for a specific microphone, so this page does not name one.

How will you hear yourself? MOTU says the M2’s “Direct monitoring” lets you press a button to hear the live input in your headphones “without routing the signal through host software on your computer”. It also quotes a round-trip latency of 2.5 ms at 96 kHz with a 32-sample buffer, which is a manufacturer figure under those conditions. Focusrite describes independent controls for headphones and monitors on the Solo.

Do you want to mix game audio on the computer? Both Focusrite and MOTU list loopback, which sends audio from the computer back to the computer so you can mix it with your microphone in your streaming software. MOTU names live streaming and podcasting as uses. If you use a separate headset for the game, you may not need it.

What the specifications say

	Scarlett Solo (4th Gen)	Scarlett 2i2 (4th Gen)	MOTU M2
Microphone inputs	1 preamp	2 preamps	2 combo inputs
Phantom power	yes	yes	48V
Mic gain range (maker’s figure)	57 dB	69 dB	not stated in the pages we read
Sample rates	44.1 to 192 kHz	44.1 to 192 kHz	44.1 to 192 kHz
Computer connection	USB-C, bus powered	USB-C, bus powered	USB-C, bus powered, class compliant
Loopback	yes	yes	yes

Sources: Focusrite product pages for the Scarlett Solo and Scarlett 2i2, and MOTU’s M2 page and specifications. Focusrite also lists “Air” modes and, on the 2i2, Auto Gain and Clip Safe, which set and protect your level automatically. MOTU lists a metal case, an LCD with level meters and MIDI in and out.

All three list sample rates up to 192 kHz, but we found no official statement of which rate streaming needs. Check your streaming software’s audio settings and keep them consistent with the interface.

Illustration of a streaming desk, not a photo of a specific model and not a Gimaxo test.

Setting levels in OBS

OBS’s documentation describes the audio mixer’s volume meter in three zones. The red zone is “close to clipping”, and speech “should reach the lower end” of it. The yellow zone is where speech should sit in its upper range, and the green zone is for background music and alert sounds. Clipping is the distortion heard when a signal can no longer be reproduced accurately. OBS also provides filters for audio sources, including a noise gate that cuts background noise when you are not speaking, a compressor that prevents levels from exceeding a threshold, and a noise suppression filter. Set the gain on the interface first, then use the meter to check it.

The guide’s own advice

• Count inputs first, features second. A single-input interface cannot take a second microphone, and the maker’s input count is the one fact you cannot work around.
• Check the gain range against the microphone. The interface’s range and the microphone’s output level are both in their specification sheets, so the comparison costs nothing.
• Decide how you will monitor yourself before you buy. Use the maker’s description of direct monitoring or of headphone controls as the test.
• Skip features you will not use. Loopback, MIDI and metering are listed by the makers as features, and none of the pages we read calls them a requirement for streaming.

What we could not verify

We found no official source for the following, so this page does not state them: that a standalone interface sounds better than a motherboard’s built-in audio, which preamps are cleanest, how many milliseconds of latency are noticeable, that 48 kHz is “the streaming standard”, that metal cases last longer, how much any model costs today, and how higher-end interfaces compare. The PreSonus AudioBox and the high-end models named in the earlier version were not checked. Check the maker’s current specification page before you buy.

Sources

Named here as plain text. Pages read in November 2026.

• Focusrite, Scarlett Solo 4th Generation and Scarlett 2i2 4th Generation product pages (specifications)
• MOTU, M2 product page and specifications page
• RØDE, “XLR or USB microphones: which is the best for gaming and streaming”
• Shure, “Difference between a dynamic and condenser microphone”
• OBS Project, Knowledge Base: Audio Mixer Guide and Filters Guide