Which small audio interface is best for one mic, MOTU M2, Audient iD4, SSL2 or PreSonus?

A Shure SM7B goes into a cheap interface, the gain knob is turned all the way to the right, and the level meter in Zoom still barely twitches. Somebody on the call says "you're a bit far away", although the mic is a hand's width from the speaker's mouth. Nothing is broken. The interface simply ran out of gain before the voice reached a normal level, and that one number on the spec sheet decided the outcome long before the box was opened.

Four names come up whenever someone asks which small interface to buy for one microphone: the MOTU M2, the Audient iD4, the SSL2 and a PreSonus AudioBox. Since October 2026 there is a fifth that belongs in the same conversation, the new Universal Audio Volt Gen 2. All of them run from the USB cable, all of them have enough gain for a condenser mic, and all but one are documented as working on a Mac with no driver (PreSonus does not say either way for the AudioBox GO). They differ in how much gain they have, how many headphones you can plug in, whether they can mix your computer's sound into the stream, and how much they cost. This comparison uses only what the makers publish.

If you are still not sure you need an interface at all (for example, you own a USB mic and wonder whether an interface would improve it), read whether you need an audio interface on a Mac first. This page is for the reader who already has an XLR mic, or is about to buy one, and now has to pick the box.

The short answer

• A dynamic mic like the SM7B, and you want no extra gadgets: SSL 2 MKII (64 dB of gain on paper) or MOTU M2 (60 dB). Both reach the roughly 60 dB Shure gives for the SM7B.
• One mic, and you want to read your level at a glance: MOTU M2. Its color screen with meters is the most useful thing in this price range for someone who is not an engineer.
• One mic, plus a second person listening on headphones: Audient iD4 MKII. Two headphone outputs on a one-mic box are unusual.
• A condenser mic and the smallest possible budget: PreSonus AudioBox GO, if you can find one in stock.
• You want built-in compression or automatic gain: look at the Volt 2 Gen 2 or the Volt Max models, not the Volt 1 Gen 2.

The rest of this page explains why, starting with the number that matters most.

MOTU M2 vs Audient iD4 vs SSL2 vs PreSonus AudioBox: the specs side by side

Every spec below comes from the maker's own spec page or manual, checked in October 2026. Prices are US street prices as of October 2026 and move often.

Two warnings about this table. EIN figures (equivalent input noise, how much hiss the preamp itself adds) are not always measured the same way, so a 1.5 dB difference between brands tells you very little. The gain figures, on the other hand, are directly comparable and they matter a lot.

Why preamp gain decides most of the choice

A condenser mic has its own small amplifier inside, powered by the 48 V phantom power the interface sends up the cable. It arrives at the interface already fairly loud, and almost any preamp can bring it up to a healthy level with gain to spare.

A dynamic mic has no amplifier. Its output is weak, and the interface has to do all the lifting. Shure says the SM7B needs around +60 dB of clean gain, and its support article points out that many interfaces stop at 40 to 50 dB, which is not enough to bring that mic to line level when you speak at a normal volume.

Put those numbers against the table:

• The PreSonus AudioBox USB 96 gives the mic input 0 to 35 dB. With an SM7B that is a long way short. With a condenser mic it is usually fine.
• The AudioBox GO gives 50 dB. Better, still short for a quiet dynamic mic and a quiet speaker.
• The Audient iD4 MKII at 58 dB and the MOTU M2 and Volt 1 Gen 2 at 60 dB sit right at Shure's figure.
• The SSL 2 MKII at 64 dB has the most headroom of the group.

"At Shure's figure" still means the knob lives near the top of its travel. Up there the preamp's own hiss is amplified along with your voice, so a soft speaker on a dynamic mic hears more of it in the pauses. That is the situation an inline booster such as a Cloudlifter or FetHead was invented for. Our piece on whether a Cloudlifter or FetHead helps covers when that extra box earns its place, and the mic preamp explainer goes deeper into what a preamp actually does.

If your mic is a condenser (an AT2020, a Rode NT1, most large-diaphragm "studio" mics), you can mostly ignore the gain column and decide on features and price.

MOTU M2: the one with a real screen

The M2 has two combo inputs, each with its own gain knob and its own 48 V switch, and a full-color LCD that shows input and output levels. That screen is the reason many people buy it. On a one-mic setup you look at a bar instead of guessing from a single LED that flickers green or red, and gain staging stops being guesswork.

What the documentation says:

• 60 dB of preamp gain, according to the M2 user guide.
• -129 dBu EIN on the mic inputs.
• Up to 192 kHz.
• Class compliant on the Mac, so it works with no driver. MOTU offers an optional Mac driver that adds a lower-latency mode and loopback channels, which let you send your computer's audio back into the stream or recording.
• Hardware direct monitoring, with a MON switch on each input.
• One headphone output.

Who it suits: one person, one dynamic or condenser mic, who wants to see the level. The second input is there when a guest shows up. The main limit is the single headphone jack.

Audient iD4 MKII: one mic, two pairs of headphones

The iD4 MKII has one XLR mic input and gives it 58 dB of gain, with a published EIN of 129 dB A-weighted. Its unusual feature is two headphone outputs, one full-size jack and one mini jack, so a producer and a host, or a teacher and a student, can both listen without a splitter. Audient also builds in a loopback mixer for bringing computer audio into a stream.

Two practical notes from Audient's own pages. On macOS the iD4 needs no driver; the iD app is used for firmware updates. And the box asks for more current than most: Audient lists a minimum of 0.9 A at 5 V, which means a USB 3.0 port or better. Plug it straight into the Mac rather than into an unpowered hub.

Who it suits: a single-mic podcaster who regularly has someone else listening along. If you will never plug in a second pair of headphones, the M2 or the SSL give more for less.

SSL 2 MKII: the most gain in the group

Most people still search for "SSL2", but the model Solid State Logic currently sells is the SSL 2 MKII, which the company presents as the successor to the original. If you see the original SSL 2 or 2+ for sale, it is the previous generation.

The MKII's numbers:

• 64 dB gain range on each of two SSL mic preamps.
• -130.5 dBu EIN, A-weighted.
• 32-bit, 192 kHz converters.
• Stereo loopback.
• Two headphone outputs, both carrying the same mix.
• Class compliant on macOS 12 and later.
• A high-pass filter button on each channel, which cuts low rumble from desks and traffic.
• About $229.99 in the US as of October 2026.

Then there is the 4K mode. SSL describes its Legacy 4K circuit as adding a controlled amount of harmonic distortion plus a forward high-frequency EQ boost. In plain terms, it brightens the top end and adds a little color on purpose. On a dark dynamic mic like the SM7B that can help speech cut through. On a bright condenser mic in an untreated room it can make sibilance sharper. It sits on a front-panel button, so you can record a sentence with it and without it and keep whichever works for your mic.

Who it suits: anyone with a gain-hungry dynamic mic who wants the best chance of avoiding an inline booster, at a price below the iD4.

PreSonus AudioBox: the cheapest, with the least gain

"PreSonus AudioBox" is a family, and the two members that matter for a single mic are the AudioBox GO (one mic input, USB-C, 50 dB of gain) and the AudioBox USB 96 (two inputs, 0 to 35 dB of mic gain, 24-bit at 96 kHz, class compliant, native on Apple silicon). Both have a Mix knob for zero-latency monitoring, which blends your mic with the computer's playback in the headphones.

As of October 2026, PreSonus's own store lists the GO at $78.99 and the USB 96 25th Anniversary edition at $79.99, and shows both as sold out. Retailers may still carry stock, but check before you plan around one.

Who it suits: someone with a condenser mic who needs the lowest price and does not need loopback. With a dynamic mic, the 35 dB of the USB 96 is the wrong tool, and you would likely end up adding an inline booster such as a Cloudlifter, which eats into the savings.

Universal Audio Volt: the new Gen 2 range

Universal Audio replaced its original Volt line with Volt Gen 2 and Volt Max models, on sale worldwide from October 1, 2026, starting at $149.

The Volt 1 Gen 2 is the one-mic model: one combo input with 60 dB of gain, a "Tone Shaping" preamp with three modes UA calls Warmth, Focus and Shine, built-in loopback, 32-bit up to 192 kHz, class compliant on macOS 12 and later. It has no Auto-Gain; UA reserves that for the Volt 2 Gen 2 and up. The Max models add six onboard compression presets based on 1176, LA-2A and VCA behavior, so a stream gets a levelled voice before it reaches the computer.

Who it suits: someone who wants compression in hardware (Max) or automatic gain setting (Volt 2 Gen 2 and up). If you want neither, the Volt 1 Gen 2 matches the M2 on gain at a lower price, with one input instead of two.

And the Scarlett?

The Focusrite Scarlett is the other name in every one of these conversations. The Scarlett Solo 4th Gen lists 57 dB of gain and -127 dBu EIN; the 2i2 4th Gen lists 69 dB, the highest figure of any box mentioned here. If you are weighing those two, Scarlett Solo or 2i2 compares them directly.

Best audio interface for streaming and podcasts

For calls and recording, every box above does the job once the gain is right. Streaming and podcasting add three requirements:

1. Loopback. If you want a game, a soundboard or a remote guest's voice in your OBS stream through the same device, loopback saves you from installing a separate routing tool. The M2 (with its optional driver), iD4 MKII, SSL 2 MKII and Volt Gen 2 all list it. PreSonus does not list it for the AudioBox models.
2. A second input. A two-person podcast at one desk needs two XLR inputs: M2, SSL 2 MKII, AudioBox USB 96 or Volt 2 Gen 2. The iD4 MKII, AudioBox GO and Volt 1 Gen 2 are one-mic boxes.
3. A second headphone output. The iD4 MKII and SSL 2 MKII have two. On the SSL both carry the same mix, which is what a co-host needs anyway.

For a solo streamer with a dynamic mic, the SSL 2 MKII or the MOTU M2 is the safe pick. For a two-person podcast with two dynamic mics, the SSL 2 MKII is the only box here with two inputs, two headphone outputs and more than 60 dB of gain at once.

What none of these interfaces do

An interface gives you a clean, loud enough signal. It does not decide how your voice sounds to the person on the other end, and that is where many buyers get disappointed after spending $200 to $270.

Here is the chain that reaches a Zoom, Teams or Discord call:

voice -> room -> mic -> interface preamp (gain) -> converter -> macOS
      -> call app's own processing (noise suppression, auto gain) -> network -> listener

The interface owns one link. The room adds echo, the mic adds its own tone, and then the call app runs its own processing on top. A $230 SSL 2 MKII in a bare room with a hard desk still sends a reflective, boomy voice into the call, just with less hiss. The fix for that sits elsewhere: placement, a bit of absorption, or processing that is set for this particular voice, mic and room.

That last option is what TunedMic does on a Mac. It adds a virtual microphone called TunedMic that takes the signal from whatever input you have, the M2, the iD4, the SSL or a USB mic, and processes it in real time. You set it up with a one-minute Sound Check: you read a short passage aloud, and TunedMic takes more than 30 measurements of your voice, your mic and your room. Then you pick one of nine profiles built from that check, and every app that uses the TunedMic mic gets the processed voice. It adds less than a tenth of a second of delay and runs entirely on the Mac.

It does not replace the interface's gain. If your preamp cannot lift an SM7B out of the noise, no software can add the missing gain cleanly. Think of the order this way: the interface gets the signal to a healthy level, and TunedMic shapes what that level sounds like on a call. It also has hard limits. It needs a Mac with Apple silicon (M1 or newer) and macOS 14 or later. It does not run on Intel Macs or on Windows.

If your current interface already gives a clean signal and the complaint is "I sound thin" or "the room echoes", try the software step before buying a second box. TunedMic has a free 7-day trial that starts at first launch, with all features and no card or account. There are no refunds after purchase, so the trial is the place to decide. The 38-second video on the home page shows what the trial asks of you first: one minute of reading aloud, after which the mic is tuned to your voice.

Three questions that settle it

1. Is your mic dynamic (SM7B, SM58, RE20, PodMic)?
   yes -> need 60 dB or more: SSL 2 MKII (64), MOTU M2 (60), Volt Gen 2 (60)
   no  -> any box here has enough gain; skip to question 2

2. Will a second person ever talk or listen at the same desk?
   talk   -> two inputs: SSL 2 MKII, MOTU M2, AudioBox USB 96, Volt 2 Gen 2
   listen -> two headphone outs: iD4 MKII, SSL 2 MKII
   never  -> one-input boxes are fine: iD4 MKII, AudioBox GO, Volt 1 Gen 2

3. Do you stream with computer audio in the mix?
   yes -> loopback: M2 (optional driver), iD4 MKII, SSL 2 MKII, Volt Gen 2
   no  -> loopback does not matter

For most people buying their first interface for one dynamic mic, all three answers point to the SSL 2 MKII, with the MOTU M2 as the choice for anyone who values the screen more than the extra 4 dB.

What to do next

Look up whether your mic is dynamic or condenser, then pick from the table using the gain column first and price second. When the interface arrives, set the gain with your real speaking voice at your real distance, aim for peaks well below the clipping point, and record ten seconds in QuickTime before your first call. If that recording is clean but still sounds boxy or distant, the remaining problem is the room and the voice, not the hardware: run the free 7-day trial on that same setup, and if TunedMic fixes what you hear, the TunedMic pricing page lists the $19 license.