Electronics / Audio Interfaces
User Guide for Focusrite Scarlett 18i20 Audio Interface
Quick guide for the Focusrite Scarlett 18i20 audio interface. Learn about setup, hardware features, software configuration, and troubleshooting.
Table of contents
Manual images
Click an image to enlargeQuick Start Guide
To get started with your Scarlett 18i20, connect the device to your computer using the provided USB cable. The interface will initially appear as a Mass Storage Device (MSD) in 'Easy Start mode'. Follow the on-screen instructions to register your product and download the Focusrite Control software. Installing Focusrite Control is essential as it installs the necessary drivers and unlocks the full potential of the interface, including sample rates up to 192 kHz and MIDI functionality.
Hardware Overview
The Scarlett 18i20 features a comprehensive set of inputs and outputs for professional recording:
- Front Panel: Includes two combo inputs (XLR/TRS) for microphones, instruments, or line signals. It also houses gain controls, 48V phantom power switches, AIR mode activation, PAD switches, monitor level controls, talkback microphone, and headphone outputs.
- Rear Panel: Features six additional combo inputs (3-8), main monitor outputs (1-2), ALT outputs (3-4), additional line outputs (5-10), optical ADAT I/O, S/PDIF I/O, MIDI I/O, and Word Clock output.
Connecting and Setup
The Scarlett 18i20 is compatible with any DAW that supports ASIO (Windows) or Core Audio (Mac). Ensure you manually select the Scarlett 18i20 as your default I/O device in your DAW's audio preferences. For surround sound setups, you can route DAW outputs to specific line outputs via Focusrite Control.
Advanced Features
- AIR Mode: Modifies the preamp frequency response to model classic transformer-based ISA preamps.
- Talkback: Uses a built-in microphone to communicate with musicians via headphones or other outputs.
- ALT Speaker Switching: Allows you to switch between two pairs of monitor speakers connected to Main (1-2) and ALT (3-4) outputs.
- ADAT/S/PDIF: Provides digital expansion for additional inputs and outputs.
- Stand-alone Mode: The interface can be configured via Focusrite Control to function as a stand-alone mixer or preamp without a computer connection.
Troubleshooting
If you encounter issues, visit the Focusrite Help Centre at support.focusrite.com for a comprehensive collection of answers to common technical queries. Ensure your computer's OS is compatible and that you have installed the latest version of Focusrite Control.
Technical Specifications
The Scarlett 18i20 supports sample rates up to 192 kHz and 24-bit resolution. It features 18 inputs (8 analogue, 8 ADAT, 2 S/PDIF) and 20 outputs (10 analogue, 8 ADAT, 2 S/PDIF). The unit is housed in a 1U rack-mountable chassis.
Official resources from the manual
Manufacturer information
Focusrite
Practical help
Common problems
Audio glitching or high CPU load
Increase the buffer size in your DAW's Audio Preferences.
Musicians hear themselves twice (echo)
Ensure your DAW software is not routing inputs to outputs while using Direct Monitoring.
Interface not recognized or limited functionality
Install Focusrite Control to disable 'Easy Start mode' and install the correct drivers.
Audio feedback loop
Turn off or turn down monitoring loudspeakers while recording with a microphone; use headphones instead.
Before use
- Connect the Scarlett 18i20 to AC mains using the supplied cable.
- Connect the interface to your computer using the provided USB cable.
- Register your product at the Focusrite website.
- Download and install the Focusrite Control software.
- Select the Scarlett 18i20 as the audio device in your DAW settings.
- Ensure speakers/headphones are connected to the appropriate outputs.
Specs in practice
- Sample Rates
- Supports 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz, and 192 kHz.
- Dynamic Range (Mic Inputs)
- 111 dB (A-weighted) for high-quality recording.
- Input Impedance (Instrument)
- 1.5 MΩ, optimized for direct connection of instruments like guitars.
Images and diagrams
- Rack mounting: Remove rubber inserts from sides and attach rack ears with M4 screws.
- Front Panel: Controls for gain, phantom power, AIR, PAD, and monitoring.
- Rear Panel: Connections for inputs, outputs, digital I/O, and power.
- Speaker Switching: Connect main monitors to outputs 1-2 and secondary monitors to outputs 3-4.
Model compatibility
- Requires a USB 2.0+ compliant port on your computer.
- Compatible with Windows (ASIO/WDM) and macOS (Core Audio).
- Optical ADAT ports are disabled at 176.4/192 kHz sample rates.
Manual page author
David Miller
Documentation analyst
Organizes user manual content into clear summaries, with attention to model details, product context, and everyday usability.