Four inputs judged on how the extra two are actually built: mic preamps, line inputs, and the outputs that go with them.
The Best 4-Input Audio Interfaces (2026)
Four-input USB interfaces for multi-instrumentalists, duos with keys, and small live sessions.
Our top picks at a glance
Best 4-input value
MOTU M4 USB-C Audio Interface, 4-Input (Interface Only)Small studios recording a mic, a guitar, and a stereo keyboard or synth at once.
Best 4-input Scarlett
Focusrite Scarlett 4i4 4th Gen, 4-Input USB Audio Interface (Interface Only)Musicians who record several instruments, a duo with keys, or a small live setup.
Best two-input alternative
MOTU M2 USB-C Audio Interface, 2-Input (Interface Only)Recordists who set levels by eye as well as by ear, and who want very low latency.
The MOTU M4 is the best four-input interface for most buyers: four real inputs, four outputs, and the clearest metering in the class, all bus powered. The Scarlett 4i4 4th Gen is the pick if you want Auto Gain, Clip Safe, and MIDI in the same box. Before buying either, check whether your extra sources are MIDI or audio: a keyboard controller over USB needs no audio input at all.
The picks, ranked
Best 4-input value
MOTU M4 USB-C Audio Interface, 4-Input (Interface Only)
The M2 grown up: four inputs, the same screen, the same low latency.
Four inputs and four outputs with LCD metering, bus powered, for little more than a good two-input box. The value pick in this class.
Strengths
- Four inputs for the price of many two-input rivals, with two mic preamps plus two line inputs.
- The same full-colour LCD metering as the M2, now covering four inputs and four outputs.
- Four balanced outputs make it easy to run a second pair of monitors or outboard gear.
Limitations
- Only two of the four inputs take a microphone; the other two are line level only.
- No Auto Gain or clip protection.
- The extra outputs are wasted if you only own one pair of monitors.
What owners report
Commonly praised
- Four inputs and four outputs for little more than a good two-input box
- the same clear LCD metering as the M2, now covering four channels
- extra outputs make a second pair of monitors easy to run
Common complaints
- Only two inputs take a microphone, the other two are line level only
- no Auto Gain or clip protection
- the extra outputs sit unused with a single pair of monitors
Recurring themes from owner reviews on retailers and forums, summarised by our editors. Updated October 2026.
| Inputs | 2 mic/line/Hi-Z combo + 2 line inputs (4-in / 4-out) |
|---|---|
| Conversion | 24-bit / 192 kHz |
| Converters | ESS Sabre32 Ultra DAC, 120 dB dynamic range on outputs |
| Metering | Full-colour LCD for all inputs and outputs |
| MIDI | MIDI in and out |
| Connection | USB-C, bus powered |
Best for: Small studios recording a mic, a guitar, and a stereo keyboard or synth at once.
Skip if: You only record one or two sources, or you want Auto Gain.
Best 4-input Scarlett
Focusrite Scarlett 4i4 4th Gen, 4-Input USB Audio Interface (Interface Only)
Four inputs and MIDI, for multi-instrumentalists and small collaborations.
Auto Gain and Clip Safe across four inputs, plus MIDI. The easiest four-input box to live with.
Strengths
- Four inputs with two mic preamps, so a mic, a guitar, and a keyboard can stay plugged in at once.
- MIDI in and out connects a keyboard controller without a separate adapter.
- Auto Gain and Clip Safe carry over from the 2i2, so the extra inputs do not add extra fiddling.
Limitations
- Needs the included 5V power supply as well as USB, so it is less grab-and-go than the bus-powered models.
- Only two of the four inputs have mic preamps; the other two are line or instrument level.
- Costs noticeably more than the 2i2 for inputs you may not use every session.
What owners report
Commonly praised
- Four inputs keep a mic, a guitar, and keys plugged in at once
- MIDI in and out removes the need for a separate adapter
- Auto Gain and Clip Safe carry over from the smaller Scarlett models
Common complaints
- The included power supply adds a brick to the desk setup
- only two inputs take a microphone, the other two are line level
- the price step over the 2i2 is hard to justify for two-input sessions
Recurring themes from owner reviews on retailers and forums, summarised by our editors. Updated October 2026.
| Inputs | 2 mic preamps + 2 line/instrument inputs (4-in / 4-out) |
|---|---|
| Conversion | 24-bit / 192 kHz |
| Mic gain range | 69 dB |
| MIDI | MIDI in and out |
| Level help | Auto Gain, Clip Safe, and Air mode |
| Power | USB-C plus included 5V power supply |
Best for: Musicians who record several instruments, a duo with keys, or a small live setup.
Skip if: You only ever record one or two sources, or your budget stops at two inputs.
Best two-input alternative
MOTU M2 USB-C Audio Interface, 2-Input (Interface Only)
The metering pick: a colour LCD that shows exactly what each input is doing.
If your fourth input would be a keyboard, remember the M2 plus a MIDI keyboard over USB may cover the session for less. Buy four inputs only when you record four audio sources at once.
Strengths
- The full-colour LCD shows level meters for every input and output, so clipping is visible before it is audible.
- ESS Sabre32 converters give the outputs a measured 120 dB of dynamic range.
- Latency is very low with the MOTU drivers, which matters when monitoring through the computer.
Limitations
- No Auto Gain or clip protection, so levels need watching.
- The software bundle is generous but takes time to install and sort through.
- Two inputs only, with no ADAT or other expansion.
What owners report
Commonly praised
- The colour LCD shows every input and output level at a glance, so clipping is seen before it is heard
- converters give playback a clean and detailed sound
- latency stays low enough to monitor through the computer comfortably
Common complaints
- No Auto Gain, so beginners must learn gain staging on their own
- the software bundle is generous but takes a while to install and sort through
- two inputs with no way to expand later
Recurring themes from owner reviews on retailers and forums, summarised by our editors. Updated October 2026.
| Inputs | 2 mic/line/Hi-Z combo inputs (2-in / 2-out) |
|---|---|
| Conversion | 24-bit / 192 kHz |
| Converters | ESS Sabre32 Ultra DAC, 120 dB dynamic range on outputs |
| Metering | Full-colour LCD for all inputs and outputs |
| MIDI | MIDI in and out |
| Connection | USB-C, bus powered |
Best for: Recordists who set levels by eye as well as by ear, and who want very low latency.
Skip if: You want Auto Gain, or you need more than two inputs.
Best if two inputs suffice
Focusrite Scarlett 2i2 4th Gen, 2-Input USB Audio Interface (Interface Only)
The default two-input interface, with clipping protection built in.
Many four-input buyers only ever use two. The 2i2 is the honest check: if your sessions are voice plus guitar, stop here.
Strengths
- Two remote-controlled mic preamps with 69 dB of gain, so quiet mics get enough level without noise creeping in.
- Clip Safe watches the input and adjusts gain if a loud moment threatens to distort.
- Auto Gain and Air mode make good levels easy for people who do not want to babysit meters.
Limitations
- Two inputs is a hard ceiling, so a drum kit or a live band needs a bigger box.
- No MIDI in or out for keyboard controllers.
- A single headphone output means sharing when two people monitor.
What owners report
Commonly praised
- Auto Gain plus Clip Safe together make ruined takes rare for beginners
- two mic preamps handle voice and guitar at the same time with room to spare
- clean sound that stays out of the way of the performance
Common complaints
- Two inputs is a hard ceiling for drums or a live band
- a single headphone socket means two listeners must share
- no MIDI connection for controllers
Recurring themes from owner reviews on retailers and forums, summarised by our editors. Updated October 2026.
| Inputs | 2 combo mic/line/Hi-Z inputs (2-in / 2-out) |
|---|---|
| Conversion | 24-bit / 192 kHz |
| Dynamic range | 120 dB |
| Mic gain range | 69 dB |
| Level help | Auto Gain, Clip Safe, and Air mode |
| Connection | USB-C, bus powered |
Best for: Home studios recording a voice and a guitar, two voices, or a stereo pair.
Skip if: You need four inputs, MIDI, or a second headphone output.
Best vocal-led four-track
Universal Audio Volt 276 USB Audio Interface, 2-Input with 76 Compressor (Interface Only)
The Volt 2 plus a real hardware compressor for vocals on the way in.
For a vocalist who overdubs one track at a time, the 276's compressor beats extra inputs. Four inputs matter for live tracking, not for layering.
Strengths
- The built-in 76 compressor tames loud vocal peaks before they reach the computer, which is hard to fix afterwards.
- Vintage preamp mode plus the compressor gives vocals a finished character straight from the input.
- The wooden side panels and larger knobs make it the most pleasant Volt to use by hand.
Limitations
- The compressor is a single fixed character, not a flexible studio compressor.
- Two inputs only, so it cannot grow into a band setup.
- Costs more than the Volt 2 for one extra feature, so it only pays off if you record vocals often.
What owners report
Commonly praised
- The built-in 76 compressor keeps vocal levels even before they reach the computer
- Vintage mode plus the compressor gives takes a finished feel straight from the input
- large knobs and wooden side panels make it pleasant to adjust by hand
Common complaints
- The compressor has one fixed character and cannot be reshaped like a plugin
- two inputs only, with no room to grow into band recording
- the premium over the Volt 2 only pays off for regular vocal work
Recurring themes from owner reviews on retailers and forums, summarised by our editors. Updated October 2026.
| Inputs | 2 XLR combo mic/line/instrument inputs (2-in / 2-out) |
|---|---|
| Conversion | 24-bit / 192 kHz |
| Compressor | Built-in 76 compressor, switchable per channel |
| Preamp character | Vintage mode, modelled on the 610 tube preamp |
| MIDI | MIDI in and out |
| Connection | USB-C, bus powered |
Best for: Vocalists and streamers who want controlled, finished-sounding takes without touching a plugin.
Skip if: You record mostly instruments, or you prefer to compress later in the mix.
Best for keys and guitar
Steinberg UR22C USB 3.0 Audio Interface, 2-Input (Interface Only)
Onboard effects and loopback, for streamers as well as recordists.
MIDI plus two audio inputs covers a keyboard controller and a guitar, which is the most common reason people think they need four inputs.
Strengths
- Onboard DSP runs reverb and channel-strip effects while you monitor, with no delay and no computer load.
- The loopback function mixes your mic with computer audio for streaming without extra routing software.
- 32-bit conversion gives the most headroom of any interface in this guide.
Limitations
- The DSP effects are basic next to full plugins, and only affect monitoring unless you print them.
- Cubase AI is included, but the full Cubase experience costs extra.
- Two inputs only, and the metal case is heavier than the plastic rivals.
What owners report
Commonly praised
- Onboard DSP effects let you hear reverb while tracking with no delay
- loopback mixes mic and computer audio for streaming without extra software
- 32-bit conversion gives generous headroom against clipping
Common complaints
- The DSP effects are basic next to full plugins and only colour monitoring unless printed
- Cubase AI is included but the full Cubase version costs extra
- the metal case is heavier than the plastic rivals for travel
Recurring themes from owner reviews on retailers and forums, summarised by our editors. Updated October 2026.
| Inputs | 2 D-PRE mic/line inputs (2-in / 2-out) |
|---|---|
| Conversion | 32-bit / 192 kHz |
| Mic preamps | 2 Class A D-PRE preamps |
| DSP | Onboard SSP3 DSP with dspMixFx effects |
| Streaming | Loopback function mixes mic with computer audio |
| MIDI | MIDI in and out |
| Connection | USB-C, bus powered |
Best for: Streamers, podcasters, and Cubase users who want effects while monitoring and an easy live mix.
Skip if: You only record music and never stream, or you want Auto Gain.
Questions, answered
Are all four inputs microphone inputs?
Not on either interface here. Both the M4 and the 4i4 give you two mic preamps plus two line or instrument inputs. A four-microphone session, like a drum kit with four mics, needs a bigger interface with four preamps, which is a different price class.
Do four-input interfaces need a power supply?
The MOTU M4 runs on USB bus power alone. The Scarlett 4i4 includes a 5V power supply in the box and uses it alongside USB. If you record on the move, that extra brick matters; if you record at a desk, it does not.
Can I use a four-input interface with just two inputs?
Yes, with no penalty. Unused inputs sit idle. The only cost is the price and the desk space, which is why this guide keeps asking whether your sessions really use four sources at once.