Electronics / Audio
User Guide for Focusrite Scarlett 18i8 3rd Gen Audio Interface
Quick start guide for the Focusrite Scarlett 18i8 3rd Gen audio interface, covering hardware setup, software installation, input/output configuration, and troubleshooting.
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The Focusrite Scarlett 18i8 3rd Gen is a professional audio interface designed for recording microphones, instruments, and line-level signals. This guide helps you set up the device, install necessary software, and configure your DAW for optimal performance.
Getting started
Connect the Scarlett 18i8 to your computer using the provided USB cable and power it with the included 12V DC power supply. Upon first connection, the device enters 'Easy Start' mode, acting as a Mass Storage Device to guide you through registration and software installation. Installing the Focusrite Control application is essential to unlock full functionality, including sample rates up to 192 kHz and MIDI I/O.
Hardware features
The front panel features four combo inputs with independent gain controls, 48V phantom power switches, and indicators for AIR mode and PAD. The AIR function models the sonic characteristics of classic Focusrite ISA preamps. The rear panel houses additional line inputs, line outputs, optical ADAT input, S/PDIF I/O, and MIDI connectors.
Connecting your equipment
Inputs 1 and 2 accept microphones, instruments, or line-level signals. Inputs 3 and 4 are for microphones or line-level signals only. Use the PAD function to reduce input levels by 10 dB if your source signal is too hot. For monitoring, connect active speakers or a power amplifier to Line Outputs 1 and 2. The ALT function allows you to switch between two pairs of monitor speakers by connecting a second pair to Line Outputs 3 and 4.
Focusrite Control
Focusrite Control is the software interface used to manage routing, monitor mixes, and global hardware settings. It is required to configure the ALT speaker switching and to route signals for zero-latency monitoring.
Troubleshooting
If you encounter issues, ensure you are using the supplied power adapter and that your computer's USB port is 2.0 compliant. For further technical support, visit support.focusrite.com.
Official resources from the manual
Manufacturer information
Focusrite
Practical help
Common problems
Audio glitching or clicks/pops
Increase the buffer size in your DAW's audio preferences.
Musicians hear themselves with an echo
Ensure your DAW 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 unlock full features.
Before use
- Use only the supplied 12V DC power adapter.
- Connect to a USB 2.0 or higher compliant port.
- Register the device at customer.focusrite.com/register.
- Install Focusrite Control software.
- Set the Scarlett 18i8 as the default audio device in your OS and DAW.
Specs in practice
- Sample Rates
- Supports up to 192 kHz for high-resolution recording.
Images and diagrams
- Front panel: Inputs 1-4, gain controls, 48V switches, and headphone outputs.
- Rear panel: Line inputs 5-8, line outputs 1-4, ADAT/SPDIF ports, and USB connection.
Model compatibility
- Compatible with Mac OS and Windows.
- ADAT input disabled at 176.4/192 kHz sample rates.
- Requires external power supply; cannot be bus-powered.
Manual page author
David Miller
Documentation analyst
Organizes user manual content into clear summaries, with attention to model details, product context, and everyday usability.