Focusrite Scarlett 18i20 4th Gen USB heliliides

Focusrite Scarlett 18i20 4th Gen — USB Audio Interface

This rack-mountable USB audio interface is built as a studio centerpiece. With 26 simultaneous inputs and 26 outputs, eight remote-controllable mic preamps, and 24-bit/192 kHz conversion, the unit handles full-band tracking and hardware synth racks. This model is the right choice for engineers needing studio-grade I/O density in a single 1U chassis.

RedNet conversion, Auto Gain, and built-in talkback

What separates this generation from earlier Scarletts is the conversion chain: AD/DA stages taken directly from Focusrite's flagship RedNet interfaces. Auto Gain sets levels across all eight preamps at once, while Clip Safe prevents digital clipping in real time. A built-in talkback microphone and Focusrite Control 2 apps complete the feature set.

Inputs, outputs, and digital expansion

Eight rear combo XLR/TRS preamps plus two front-panel XLR/TRS inputs (with switchable Hi-Z instrument mode) cover every tracking scenario. Ten balanced 6.3 mm TRS line outputs drive two pairs of monitors plus outboard gear. ADAT (dual optical, up to 16 channels at 48 kHz) and S/PDIF expand the system; AES/EBU is not supported.

• Number of Channels: 18 — base input count before ADAT expansion
• Number of Preamps: 8 — remote-controllable via Focusrite Control 2
• Phantom Power: Yes (independent per channel)

24-bit/192 kHz conversion with RedNet-derived AD/DA

The fully shielded preamp section delivers 69 dB of clean gain — enough for ribbon, dynamic, and condenser microphones including low-output models. Conversion runs at 24-bit/192 kHz with 122 dB dynamic range on the D/A side, and Air Mode adds two flavors of console-style coloration.

• Sample Rate: 192 kHz / 24-bit
• Bit Depth: 24-bit
• Mic Preamp Gain Range: 69 dB

Line outputs, headphone amps, and routing

Ten balanced 6.3 mm TS line outputs feed two pairs of monitors with hardware A/B switching. Two independent custom headphone amplifiers deliver clean playback for high-impedance cans. Loopback routes stereo audio into the DAW, and Focusrite Control 2 exposes six onboard mixers for custom cue mixes.

• Outputs: Jack 6.3 mm TS (balanced) — 10 line outs plus 2 headphone outs
• Headphone Output: Yes (2 independent)
• Connectivity: USB Type-C (USB 2.0 protocol)