Scarlett 4-Channel Audio Interface: Using the Scarlett with Audacity

Let’s break down how the Focusrite Scarlett 3rd Gen 4-channel interface works with Audacity so you can record, monitor and manage multiple tracks. I’ll go from concept to practical setup.

How the Scarlett Communicates with Audacity

The Scarlett 4i4 acts as a USB audio interface, which means it converts analog audio signals (microphones, instruments) into digital audio the computer can understand. It also converts digital audio back to analog for playback in headphones or speakers.

Signal Flow:

1. Input (Analog) → Your mic, instrument or line-level source plugged into the Scarlett.

2. Preamp & ADC (Analog-to-Digital Converter) → Scarlett converts the analog voltage into digital audio.

3. USB connection → Digital audio is sent to your computer.

4. Audacity sees the Scarlett as an audio device. You assign each input to a track in Audacity.

5. Playback (DAC) → Audacity outputs digital audio → Scarlett converts to analog → Headphones/monitors.

Essentially, the Scarlett is the bridge between real-world sounds and Audacity’s digital workspace.

Getting started on a new project

Configuring Audacity

1. Open Audacity → Edit → Preferences → Devices

2. Host:

   • Windows: Choose ASIO if available (for lowest latency), otherwise MME or WASAPI

   • Mac: Core Audio

3. Recording Device: Scarlett 4i4 (or Focusrite ASIO driver)

4. Playback Device: Scarlett 4i4

5. Set Channels = 2 (stereo) or more if Audacity detects multichannel inputs

Note: Audacity only allows recording from one stereo pair at a time in the standard interface. For full 4-channel multitrack recording, you’ll need Audacity multichannel mode.

Enabling inputs

1. Open Audacity → Tracks → Add New → Stereo Track (or Mono Track for mic 1)

2. Click Track Input → Select the corresponding Scarlett input:

   • Input 1 → Track 1 (Your mic)

   • Input 2 → Track 2 (Guest mic)

   • Input 3/4 → Instruments or other sources

3. Arm track for recording → Hit Record

Now each input can record to its own track.

Monitoring Audio

Two ways to monitor:

Option 1: Direct Monitoring (Recommended)

• Use the Direct Monitor switch on the Scarlett.

• Zero latency → performers hear themselves in real time.

Option 2: Audacity Software Monitoring

• Track → Click the Input Monitoring button (microphone icon)

• Slight latency depending on buffer size

Tip: For live podcast or music, Direct Monitor is best. Software monitoring is better for hearing effects, but adds delay.

Multitrack recording example (podcast):

• Arm all tracks → Record → Each track is isolated

• Post-editing: apply EQ, compression, and effects independently

Playback in Audacity

• Output → Scarlett → Headphones or studio monitors

• Can adjust volume independently using Scarlett’s headphone knobs