Focusrite SCARLETT 18I8 3RD GEN USB Audio Interface

Overview

High channel count. Small footprint. Whatever you’re recording, wherever you are, take your whole studio with you. 18i8 is studio sound for the whole band.

The four 3rd Generation Scarlett mic preamps sound great straight out of the box. Air mode recreates the legendary effect of Focusrite's ISA mic pres and makes vocals and guitars shine. The high-impedance, high-headroom instrument inputs are great for recording guitar or bass without clipping, while our iconic Gain Halos make it easy to set input levels fast. Four balanced outputs with Anti Thump speaker switching are hum-free for pristine monitoring and are ideal as FX sends. Two powerful headphone outputs with individual level controls let you monitor, mix and master however you want. Loopback makes streaming and sampling simple. And it comes with some of the best-loved tools in the business, including Ableton Live Lite, Avid Pro Tools Artist and Hitmaker Expansion – with plugins from legendary Auto-Tune® creators Antares®, Brainworx®, Softube®, Landr, XLN Audio®, Relab and more.

Key Features

• Eight inputs and four outputs; four 3rd Generation mic pres, two Hi-Z instrument inputs, four fixed line inputs, and four balanced outputs plus ADAT input for up to eight more channels.
• Air Mode breathes life into vocals and acoustic instruments.
• 24-bit/192 kHz converters deliver studio-quality sound.
• Gain Halos make setting levels simple.
• Two powerful headphone outputs with independent level controls.
• Focusrite Control makes it easy to route audio and create the perfect monitor mix.
• Loopback makes streaming and sampling simple.
• Flexible connectivity, with MIDI and S/PDIF.
• USB-C connectivity, compatible with MacOS and Windows.
• Includes Ableton Live Lite, three months of Pro Tools Artist, and the Hitmaker Expansion, with plugins from Antares, Softube, Landr, XLN Audio and more.
• Three-year warranty and award-winning customer support for life.

How the 18 Inputs and 8 Outputs Are Actually Counted

This is the single most common point of confusion with the 18i8. The name does not mean eighteen physical sockets on the chassis — it means eighteen simultaneous input channels available to your DAW, and those channels come from three different places. Understanding the split is what tells you whether the 18i8 is genuinely big enough for your session.

The important consequence: out of the box you have eight analogue inputs, four of them with mic preamps. The remaining ten channels only exist once you add ADAT gear and an S/PDIF source. If you need more than four microphones live on day one, you need an ADAT preamp alongside the 18i8, or a bigger interface such as the eight-preamp Scarlett 18i20 3rd Gen.

On the output side, the eight output channels are the four balanced line/monitor outputs plus the two independent stereo headphone feeds. An S/PDIF output and MIDI In and Out round out the connectivity.

Key Specifications

Model Comparison: Which Scarlett Do You Actually Need?

The 18i8 is the middle of three 3rd Generation multi-channel Scarletts. The table below also includes the 4th Generation 18i16, because that is the closest current-generation equivalent — see the section below for why there is no 4th Gen 18i8.

Choose the 8i6 if two mic inputs is enough and you will never expand — it has no ADAT port, so its channel count is fixed. Choose the 18i8 when you need four preamps now and want the option to reach eighteen inputs later over ADAT, in a desktop footprint. Choose the 18i20 when you need eight mic preamps on the box itself, ten balanced outputs for multi-zone monitoring or outboard sends, a built-in talkback mic, and a 1U rack chassis.

3rd Gen vs 4th Gen: An Honest Answer

Buyers researching the 18i8 almost always end up asking whether they should wait for a 4th Generation version. The short answer: Focusrite does not make a 4th Generation Scarlett 18i8. When Focusrite extended the 4th Gen range to larger-format interfaces, it launched the 16i16, 18i16 and 18i20 — the 18i8 has no direct 4th Gen successor. The nearest current-generation equivalent is the 18i16 4th Gen, which shares the 18-input count and four mic preamps but doubles the output count to sixteen and adds an ADAT output.

What 4th Gen adds over 3rd Gen, according to Focusrite:

• Auto Gain and Clip Safe — automatic level setting and clip protection, neither of which exists on 3rd Gen hardware.
• Air with Presence and Harmonic Drive — 3rd Gen Air provides Presence only; 4th Gen adds a harmonic drive stage on top.
• Higher converter dynamic range — 122 dB on the 18i16 4th Gen D-A stage, versus 108 dB on the 18i8 3rd Gen line outputs.
• Focusrite Control 2 with desktop and mobile control, plus output metering.

What has not changed: both generations are 24-bit / 192 kHz, both use USB-C, both need an external PSU at this channel count, and both use the same ADAT expansion approach. If Auto Gain, Clip Safe and sixteen outputs matter to your workflow, the 18i16 4th Gen is the better buy. If you want four preamps, ADAT expansion and 24-bit/192 kHz conversion at the lower 3rd Gen price, the 18i8 remains a fully supported product — Focusrite still publishes current Mac and Windows drivers for it, and it works with both the original Focusrite Control and Focusrite Control 2.

What's in the Box

• Focusrite Scarlett 18i8 3rd Gen USB audio interface
• External power supply
• USB-C cable
• Getting Started guide and safety information
• Software bundle redemption — Ableton Live Lite, three months of Pro Tools Artist, and the Hitmaker Expansion with plugins from Antares, Brainworx, Softube, Landr, XLN Audio, Relab and more

Focusrite revises the bundled software offer from time to time; as currently listed on Focusrite's own product page the bundle also includes Avid Pro Tools Intro+ and Cubase LE alongside Ableton Live Lite and the Hitmaker Expansion. Check Focusrite's product page linked below for the offer in force at the time of purchase.

Deployment, Compatibility and Rack Mounting

• macOS: supported on both Apple Silicon and Intel Macs, per Focusrite.
• Windows: supported on Intel, AMD and Arm64 processors, per Focusrite.
• Connection: USB-C connector running the USB 2.0 protocol. USB 2.0 is not a limitation at this channel count — 18 in / 8 out at 24-bit/192 kHz fits comfortably within USB 2.0 bandwidth.
• Power: the 18i8 is not bus-powered. The supplied external PSU must be connected, which also means it will not run from a laptop alone in the field.
• Rack mounting: the 18i8 3rd Gen is a desktop chassis measuring 9.5 × 6.3 × 2.4 in and weighing 3.4 lb. If you need a 19-inch rack unit from the same generation, the Scarlett 18i20 3rd Gen is the 1U rack-mount model in the range.
• Channel expansion: the ADAT optical input accepts up to eight additional channels from an external ADAT preamp or converter — the usual pairing is a Scarlett OctoPre, which takes the 18i8 from four mic preamps to twelve.
• Streaming and podcasting: loopback is available through Focusrite Control, letting you capture computer playback — browser audio, a remote guest, a backing track — as an input alongside your microphones without a physical loop cable.
• Monitoring: low-latency monitor mixes are built in Focusrite Control rather than in the DAW, so performers hear themselves without waiting on the round trip through plugins.

Documentation and Resources

• Focusrite Scarlett 18i8 3rd Gen official product page and specifications
• Scarlett 18i8 3rd Gen User Guide — hardware features, getting started, and full specifications
• Scarlett 18i8 3rd Gen downloads — Focusrite Control and Focusrite Control 2 for Mac and Windows, plus the user guide PDF

Frequently Asked Questions

What does "18-in, 8-out" actually mean on the 18i8?
Eighteen simultaneous input channels to your DAW, made up of eight analogue inputs on the unit (four with mic preamps), up to eight channels over the ADAT optical input, and two channels over S/PDIF. The eight outputs are the four balanced line outputs plus the two independent stereo headphone feeds. Out of the box, without any external gear, you have eight analogue inputs and four mic preamps.

Is there a 4th Gen Scarlett 18i8?
No. Focusrite's 4th Generation multi-channel models are the 16i16, 18i16 and 18i20 — the 18i8 was not carried forward. The closest 4th Gen equivalent is the 18i16, which keeps the 18 inputs and four mic preamps but offers sixteen outputs and adds an ADAT output. The 18i8 3rd Gen remains a supported product with current Mac and Windows drivers.

Should I buy the 18i8 3rd Gen or the 18i16 4th Gen?
Buy the 18i16 4th Gen if you want Auto Gain and Clip Safe, the Air Presence plus Harmonic Drive circuit, 122 dB D-A dynamic range, output metering, sixteen output channels, and an ADAT output. Buy the 18i8 3rd Gen if four preamps, eight analogue inputs, ADAT expansion, four balanced outputs and 24-bit/192 kHz conversion cover your needs at a lower price. Both share the same core resolution, USB-C connection and external-PSU requirement.

How does the 18i8 compare to the 18i20 3rd Gen?
Both offer 18 input channels, but the 18i20 puts eight mic preamps on the unit itself rather than four, has ten balanced outputs instead of four, has two ADAT inputs and two ADAT outputs instead of one input, includes a built-in talkback mic, and ships as a 1U rack-mount chassis. Choose the 18i20 for tracking full bands live, multi-zone monitoring, or outboard sends; choose the 18i8 for a desktop footprint with room to expand over ADAT.

How does the 18i8 compare to the 8i6 3rd Gen?
The 8i6 has two mic preamps and no ADAT port at all, so its eight input channels are the ceiling. The 18i8 doubles the preamp count to four, adds two more line inputs, and adds the ADAT optical input that takes it to eighteen channels. If there is any chance you will need more than eight inputs, the 18i8 is the one that can grow.

Can I add more microphone inputs later?
Yes. Connect an eight-channel ADAT preamp or converter — typically a Scarlett OctoPre — to the 18i8's ADAT optical input over a single optical cable. That takes you from four mic preamps to twelve without replacing the interface.

Is the 18i8 rack-mountable, and is it bus-powered?
The 18i8 3rd Gen is a desktop unit, 9.5 × 6.3 × 2.4 in and 3.4 lb; the 18i20 3rd Gen is the 1U rack model in the range. The 18i8 is not USB bus-powered — the supplied external power supply is required, so plan on a mains outlet at the desk.

Does it work with Apple Silicon Macs and Windows on Arm?
Yes. Focusrite lists macOS support for both Apple Silicon and Intel Macs, and Windows support for Intel, AMD and Arm64 processors. Current drivers, Focusrite Control and Focusrite Control 2 are available from the Focusrite downloads page linked above.

Does the 18i8 have loopback for streaming, and how do I keep monitoring latency low?
Loopback is built in and configured in Focusrite Control, so you can record computer playback as an input channel alongside your mics — useful for streaming, podcast remotes and sampling. For tracking, build the performer's monitor mix inside Focusrite Control rather than in your DAW; that path bypasses plugin processing and keeps what the performer hears tight.

Related Products

• Focusrite Scarlett 18i20 3rd Gen USB Audio Interface — eight mic preamps and a 1U rack chassis
• Focusrite Scarlett 8i6 3rd Gen USB Audio Interface — two preamps, no ADAT expansion
• Focusrite Scarlett 2i2 4th Gen USB Audio Interface — 4th Gen Auto Gain and Clip Safe in a two-channel unit
• Focusrite Clarett+ 4Pre 18-in/8-out Audio Interface — same channel count, Clarett+ preamps and converters
• Microphones collection — pair the 18i8's four preamps with condenser and dynamic mics