Gear article
Focusrite Scarlett 18i20 4th Gen
The Focusrite Scarlett 18i20 4th Gen is a rack-mountable USB audio interface designed for project studios and multi-channel recording setups. It features eight 4th Generation microphone preamps and pro-grade conversion technology derived from the flagship RedNet range.

Overview
The Focusrite Scarlett 18i20 4th Gen serves as the high-connectivity flagship of the Scarlett range, tailored for users who require significant I/O for outboard gear and multi-track recording. It integrates eight mic preamps with a variety of line and instrument inputs to accommodate full band sessions or complex studio routing. The unit is designed for professional reliability while maintaining the accessibility characteristic of the Scarlett series.
Key Features and Preamplification
Central to the 4th Generation hardware are the eight mic preamps, which provide 69dB of gain. This high gain range allows for the clean recording of dynamic performances and lower-output microphones without excessive noise.
Connectivity includes: * Eight 4th Gen mic preamps. * Two Hi-Z instrument inputs for direct connection of guitars and basses. * Eight line inputs for external hardware such as synthesizers or mixers. * Pro-grade 24-bit/192kHz converters.

Smart Recording Workflow
The 18i20 4th Gen introduces automated workflow features to assist in technical setup. The 'Auto Gain' function listens to the incoming signal and sets the optimal recording level within seconds. To prevent digital distortion, the 'Clip Safe' feature monitors the input levels and automatically adjusts the gain if the signal nears clipping, ensuring that take-destroying peaks are avoided during volatile performances.
Audio Quality and Fidelity
The audio fidelity of the 18i20 is driven by converters sourced from Focusrite's high-end RedNet range. These converters offer a 122dB dynamic range, enabling the capture of both subtle nuances and loud sound sources with transparency. The result is a sonic character that is neutral and detailed, suitable for high-resolution professional productions.
Comparison to Alternatives
Within the Focusrite ecosystem, the 18i20 offers significantly more I/O than the Scarlett 2i2 4th Gen, which is designed for solo creators. In the broader market, it competes with units like the MOTU 10Pre, which also offers high-channel counts. While entry-level options like the Behringer U-PHORIA UMC202HD, M-Audio M-Track Solo, or Tascam US-2x2HR provide basic recording capabilities at a lower price point, they lack the 18i20's high dynamic range, large preamp count, and automated gain features.
Related gear
£319.00 ($405)Blackstar
Blackstar Polar 4 Audio Interface
£1,499.00 ($1,904)Motu
MOTU 10Pre USB/Thunderbolt Audio Interface
£40.80 ($52)M-Audio
M-Audio M-Track Solo 2 Channel USB Interface
£134.00 ($170)Tascam
Tascam US-2x2HR USB Audio Interface
£54.70 ($69)Behringer
Behringer U-PHORIA UMC202HD USB Audio Interface
£299.00 ($380)M-Audio
M-Audio AIR 192 6 Audio Interface and BX5-D3 Monitor Bundle
£300.00 ($381)Focusrite
Focusrite Scarlett 2i2 4th Gen Audio Interface
Frequently asked questions
- How many mic preamps does the Scarlett 18i20 4th Gen have?
- It features eight 4th Generation microphone preamps, offering a high gain range of 69dB for recording various sound sources.
- What is the dynamic range of the converters?
- The interface uses pro-grade converters derived from the RedNet range, providing a dynamic range of 122dB.
- What does the Auto Gain feature do?
- Auto Gain automatically sets the ideal recording level for your input signal within seconds, simplifying the setup process.
- How does the Clip Safe feature work?
- Clip Safe constantly monitors the input levels and automatically adjusts the gain if it detects a risk of clipping, preventing digital distortion.
- Can I plug a guitar directly into the 18i20?
- Yes, it includes two Hi-Z instrument inputs specifically designed for the high-impedance signals of electric guitars and basses.
- What is the maximum recording resolution?
- The Scarlett 18i20 4th Gen supports audio recording and playback at resolutions up to 24-bit and 192kHz.
- How many total line inputs are available?
- In addition to the mic preamps, the unit provides eight line inputs for connecting outboard gear like synthesizers and drum machines.
- Is this interface suitable for professional project studios?
- Yes, with its high channel count, RedNet-derived conversion, and 122dB dynamic range, it is designed to meet the needs of project studios.
- What is the typical price for the Scarlett 18i20 4th Gen?
- The typical price for this audio interface is approximately £600.
- How does the 18i20 4th Gen compare to the Scarlett 2i2?
- The 18i20 offers much higher I/O capacity with eight preamps compared to the two found on the 2i2, making it better for full band recording.
- Does the 18i20 4th Gen use the same converters as the RedNet range?
- Yes, Focusrite has utilised converters derived from their flagship professional RedNet range for this 4th Generation interface.
- What type of connectivity does it use for the computer?
- It is a USB audio interface, allowing for high-speed data transfer and compatibility with modern digital audio workstations.
