Focusrite Scarlett Solo 4th Gen

accessories Hi-Fi Audio Pro Tools Sound Cards

Focusrite Scarlett Solo 4th Gen

Device Type: 2-In / 2-Out USB-C Audio Interface
•
Resolution: 24-bit / 192 kHz (AES17)
•
Line Out Dynamic Range: 120 dB (RedNet Tier)
•
Preamp Gain Range: 57 dB
•
Inputs: 1x XLR Mic + 1x 1/4″ Line/Inst
•
Outputs: 2x 1/4″ Balanced TRS + 1x 1/4″ Phones
•
Bus Power: USB-C (5V DC @ 900 mA)

1. Core Specifications Overview

Parameter Engineering Specification
Product Identity & Platform
Manufacturer Focusrite Audio Engineering Limited (High Wycombe, UK)
Model Scarlett Solo (4th Generation)
Interface Class USB Audio Class 2.0 (High-Speed USB-C)
Measurement Standard All audio specifications measured strictly following AES17 standard
Digital Audio Subsystem
Conversion Resolution 24-bit linear PCM conversion
Supported Sample Rates 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz, 192 kHz
Clocking Architecture Internal master clocking; low-jitter crystal oscillator
DAC Performance Tier Flagship D/A conversion offering 120 dB dynamic range (derived from Focusrite RedNet series)
I/O Channel Topology
Physical Analog Inputs 2 channels (Ch 1: Front 1/4″ Line/Instrument; Ch 2: Rear XLR Microphone)
Virtual DSP Inputs 2 channels (Ch 3-4: Stereo Hardware Loopback)
Physical Analog Outputs 2 channels (Outputs 1-2: Left & Right balanced TRS monitor outputs)
Headphone Output Feed Mirrors Outputs 1-2 with independent dedicated analogue potentiometer

2. Analog Input Specifications

Parameter Microphone Input
Ch 2 • Rear XLR		 Line Input
Ch 1 • Inst Off		 Instrument Input
Ch 1 • Inst On
Physical Connector Neutrik 3-pin XLR 6.35 mm (1/4″) TRS 6.35 mm (1/4″) TS
Frequency Response 20 Hz – 20 kHz ± 0.06 dB 20 Hz – 20 kHz ± 0.05 dB 20 Hz – 20 kHz ± 0.15 dB
Dynamic Range (A-weighted) 113 dB 113 dB 112 dB
THD+N -100 dB (-1 dBFS @ min gain) -100 dB (min @ min gain) -80 dB (min @ 8 dB gain)
Noise EIN (A-weighted) -127 dBu N/A N/A
Max Input Level (@ min gain) +9.5 dBu +22 dBu +12 dBu
Gain Range 57 dB 57 dB 57 dB
Input Impedance 3 kΩ 60 kΩ 1 MΩ (Hi-Z)
Phantom Power +48V DC switchable N/A N/A
Air Circuit Support Presence & Drive Presence & Drive Presence & Drive

3. Analog Output Specifications

Parameter Line Outputs 1 & 2
Balanced 1/4″ TRS		 Headphone Output
Stereo 1/4″ TRS
Physical Connectors 2x Rear 6.35 mm (1/4″) TRS jacks 1x Front 6.35 mm (1/4″) stereo TRS jack
Circuit Topology Electronically balanced line drivers High-current stereo headphone amplifier
Frequency Response 20 Hz – 20 kHz ± 0.02 dB 20 Hz – 20 kHz ± 0.1 dB (@ 33 Ω / 300 Ω)
Dynamic Range (A-weighted) 120 dB 112 dB (@ 33 Ω) • 115 dB (@ 300 Ω)
THD+N -109 dB -97 dB (@ 33 Ω) • -102 dB (@ 300 Ω)
Maximum Output Level +16 dBu +2.5 dBu (@ 33 Ω) • +10 dBu (@ 300 Ω)
Output Impedance 200 Ω 50 Ω
Recommended Load Active Studio Monitors / Line-In Headphones up to 300 Ω nominal load
Level Potentiometer Continuous analogue potentiometer Continuous analogue potentiometer (independent)

4. Hardware Controls, Metering & Physical Layout

Control / Indicator Physical Action Functional Behavior
Dynamic Gain Halos Concentric rotary rings Tri-color LED metering around each gain knob:

• Green: Signal present (-42 dBFS to -6 dBFS)

• Amber: Pre-clip warning (-6 dBFS to 0 dBFS)

• Red: Digital clipping overload (0 dBFS)
Inst Mode Switch Latching push-button Toggles Input 1 impedance between Line Level (60 kΩ, white LED) and Instrument Hi-Z (1 MΩ, green LED).
Air Mode Engine Multi-state push-button Cycles through 3 distinct analogue and DSP sonic profiles:

• Off (White LED): Transparent, ultra-linear preamplification.

• Air Presence (Green LED): Pure analogue circuit boosting high-frequency clarity and acoustic presence.

• Presence & Harmonic Drive (Amber LED): Analogue presence boost combined with DSP harmonic drive (up to 96 kHz).
+48V Phantom Power Push-button Sends +48V DC phantom power to the rear XLR input for studio condenser microphones.
Direct Monitor Push-button Routes incoming signals directly to monitor and headphone outputs with zero round-trip digital latency.
Hardware Loopback Internal virtual routing Feeds computer system audio outputs back into DAW Inputs 3-4 for livestreaming and podcasting.

Front Panel Schematic

+-----------------------------------------------------------------------------------------------+
|  FOCUSRITE                                                            SCARLETT SOLO 4th Gen   |
|                                                                                               |
|  [ INST ]       ( GAIN 1 )       ( GAIN 2 )       [ 48V ]        (  MONITOR  )   ( PHONES )   |
|    6.35mm     (O) Halo Ring    (O) Halo Ring                                                  |
|  Line / Inst                                      [ AIR ]                                     |
|  Jack In 1                                     [ DIRECT MON ]      MAIN OUTPUT    HEADPHONE   |
|                                                                    LEVEL POT      LEVEL POT   |
+-----------------------------------------------------------------------------------------------+

Rear Panel Schematic

+-----------------------------------------------------------------------------------------------+
|  [ K ]              [ USB-C ]              ( R )              ( L )               [ XLR IN ]  |
|  Kensington        5V DC 900mA        SPEAKER OUTPUTS (BALANCED) 1/4" TRS          MICROPHONE |
|  Security Slot     Power & USB 2.0         Right              Left                  INPUT 2   |
+-----------------------------------------------------------------------------------------------+

5. Physical, Electrical & Environmental Characteristics

Characteristic Specification
Dimensions (H × W × D) 46.5 mm × 143 mm × 96 mm (1.83 in × 5.63 in × 3.78 in)
Unit Weight 382 g (0.84 lbs)
Chassis Construction Precision anodized aluminium unibody enclosure with rubberized feet
Power Supply Protocol USB-C bus powered (USB 2.0 standard protocol)
Power Consumption 5V DC @ 900 mA (4.5 Watts maximum)
Standalone Operation Supported; powers via external standard 5V USB-C wall adapter without computer for direct monitoring
Ambient Operating Temp Up to 40 °C / 104 °F maximum ambient operating temperature
Physical Security Integrated Kensington Security Slot (rear chassis)

6. Driver Architecture & DAW Integration

Host Environment Driver Architecture Configuration & Control
Apple macOS Class-compliant Core Audio Focusrite Control 2 application (software switching, firmware updates)
Microsoft Windows Focusrite USB ASIO driver Focusrite Control 2 with system tray buffer size and sample rate control
Avid Pro Tools Setup • Windows: Setup > Playback Engine > Focusrite USB ASIO

• macOS: Setup > Playback Engine > Scarlett Solo 4th Gen

• I/O Routing: Inputs 1-2 (Mic/Line), Outputs 1-2 (Monitors/Phones), Inputs 3-4 (Loopback)
Software Bundle Pro Tools Artist subscription license, Ableton Live Lite, Focusrite Control 2, Hitmaker Expansion suite (Antares Auto-Tune Access, Softube Marshall Silver Jubilee 2555, Native Instruments MASSIVE, Landr Studio mastering tools, Brainworx bx_console Focusrite SC, XLN Audio Addictive Keys & Drums).