The front panel includes all the input gain and monitoring controls as well as two of the input connectors for Mic, Line, and Instrument signals.
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Inputs 1 and 2 – “Combo” input sockets - connect microphones, instruments (e.g., guitar), or line level signals here. Combo sockets accept both XLR and ¼” (6.35 mm) jacks. Microphones connect using XLR plugs: instruments and line level signals connect via ¼” (6.35 mm) jack plugs of either TS or TRS type. The preamp gain is appropriate for microphones when an XLR plug is inserted, and for higher level signals when a jack plug is inserted. Do not connect anything other than a microphone - e.g., the output of a sound module or FX unit - via an XLR plug, as the signal level will overload the preamp, resulting in distortion. If phantom power is enabled, you may damage your equipment.
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48V – two switches (1-4, 5-8) enabling 48 V phantom power at the XLR contacts of the Combo connectors for mic inputs 1-4 and 5-8 respectively. (Note that inputs 3 to 8 are on the rear panel.) The switches each have an associated red LED indicating phantom power is selected.
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Gain 1 & 2 – adjust the input gain for the signals at Inputs 1 and 2 respectively.
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INST – two switches changing the input configuration for the jack contacts at Inputs 1 and 2. When INST is selected, the gain range and input impedance are altered (relative to LINE), and the input is made unbalanced. This optimises it for the direct connection of instruments (via a 2-pole (TS) jack plug). When INST is off, the inputs are suitable for the connection of line level signals. Line level signals may be connected either in balanced form via a 3-pole (TRS) jack or unbalanced via a 2-pole (TS) jack. ‘INST’ illuminates red when Instrument mode is selected. INST may also be selected from Focusrite Control.
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AIR – eight yellow LEDs indicating selection of AIR mode for each channel. AIR mode, selected from Focusrite Control, modifies the frequency response of the input stage to model the classic, transformer-based Focusrite ISA microphone preamps.
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PAD – eight switches to select the PAD function for each channel. PAD decreases the signal level going to your DAW by 10 dB; use when the input source has a particularly high level. ‘PAD’ illuminates red when active. PAD may also be selected from Focusrite Control.
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Gain 3 to 8 – adjust the input gain for the signals at Inputs 3 to 8 respectively. (Note that the connectors for these inputs are on the rear panel.)
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Input meters – eight 5-segment LED bar graph meters indicating the signal levels of the eight analogue input signals. The meters show signal level after the input gain stage, and thus their indication is affected by the gain controls. The LEDs illuminate at -42 (green, “signal present”),
-18 (green), -6 (green), -3 (yellow) and 0 dB (red). A level of 0 dBFS results in digital clipping, and should always be avoided.
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USB active LED –a green LED illuminates when the Scarlett is connected and recognised by your computer.
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Locked – a green LED which confirms clock synchronisation, either to the Scarlett 18i20 3rd Gen’s internal clock or to an external digital input.
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MIDI LED – green LED, illuminates when MIDI data is received at the MIDI IN port.
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MONITOR – main monitor output level control: this will normally control the level at the main monitor outputs on the rear panel, but can be configured in Focusrite Control to adjust the level at any of the unit’s ten analogue outputs.
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DIM and MUTE – two switches to control the 18i20’s monitor outputs; DIM reduces the output levels by 18 dB, while MUTE turns the outputs off. By default, these switches affect the MAIN monitor outputs 1 and 2, but in Focusrite Control you can configure them to control any of the analogue outputs. The switches each have an associated LED (DIM: yellow, MUTE: red) indicating the function is selected. DIM and MUTE may also be selected from Focusrite Control.
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Talkback microphone
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TALKBACK – press and hold this button to activate talkback. When active, ‘TALKBACK’ illuminates green, and the talkback mic [14] may be routed to the 18i20’s various outputs. By default, talkback routes to the two headphone outputs [17], but the routing may be configured in Focusrite Control to feed any combination of outputs. This button is ‘momentary’ – talkback is only active while it is pressed. Talkback may also be activated, momentary or latching, from Focusrite Control.
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ALT – when the ALT function is enabled in Focusrite Control, pressing this button diverts the main monitor mix from MAIN LINE OUTPUTS 1 and 2 to ALT LINE OUTPUTS 3 and 4. Connect a pair of secondary monitor speakers to the ALT outputs, and select ALT to switch between your main monitors and the secondary pair. ‘ALT’ illuminates green when selected. This function may also be selected from Focusrite Control. (Note that when ALT is enabled, the line outputs not in use are muted: e.g., to use Line Outputs 3 and 4 for another purpose, first unmute them in Focusrite Control.)
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Headphone volume 1 and 2 – connect one or two pairs of headphones at the two ¼” (6.25 mm) TRS jack sockets below the controls. The headphone outputs always carry the signals currently routed to analogue outputs 7/8 and 9/10 (as stereo pairs) in Focusrite Control.
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POWER – AC power switch.
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MIC/LINE INPUTS 3 to 8 – Combo type input sockets - connect further microphones or line level signals via XLR or ¼” (6.35 mm) jacks as appropriate. Either ¼” TRS (balanced) or TS (unbalanced) jack plugs can be used for line level signals.
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LINE OUTPUTS 1 and 2 (MAIN) – two balanced analogue line outputs on ¼” (6.35 mm) jack sockets; use TRS jacks for a balanced connection or TS jacks for unbalanced. We recommend the use of balanced connections wherever possible, to minimise grounding and hum problems. These will generally be used for driving the main L and R speakers of your monitoring system. However, the signals at the outputs may be defined in Focusrite Control
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LINE OUTPUTS 3 and 4 (ALT) – connect a secondary pair of monitor speakers here To use the 18i20’s ALT function. The outputs are electrically identical to Line Outputs 1 and 2. The signals at the outputs may be defined in Focusrite Control.
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LINE OUTPUTS 5 to 10 – six further line outputs with identical electrical characteristics to Line Outputs 1 to 4. The signals available at these outputs are defined in Focusrite Control, and can be used for driving the additional speakers in a multichannel monitoring system, or to drive outboard FX processors.
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OPTICAL IN and OUT – four TOSLINK connectors for handling eight channels of digital audio in ADAT format at either 44.1/48 kHz or 88.2/96 kHz sample rates. At 44.1/48 kHz sample rate, only the right-hand port of each pair is used; at 88.2/96 kHz sample rate, both ports are used, with the right-hand port carrying ADAT Channels 1-4 and the left-hand port carrying ADAT Channels 5-8. (Note that the optical input and output are disabled when sample rates of 176.4/192 kHz are in use.) The left-hand port of each pair (IN and OUT) may be configured to receive and transmit a two-channel S/PDIF signal from/to an external source equipped with optical S/PDIF I/O: this option is selected from Focusrite Control. Please refer to the Channel Listing tables in the Appendix section for more details.
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WORD CLOCK OUT – a BNC connector carrying the Scarlett 18i20 3rd Gen’s word clock; this may be used to synchronise other digital audio equipment forming part of the recording system. The source of sample clock synchronisation used by the Scarlett 18i20 3rd Gen is selected from Focusrite Control.
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MIDI IN and MIDI OUT – standard 5-pin DIN sockets for connection of external MIDI equipment. The Scarlett 18i20 3rd Gen acts as a MIDI interface, allowing MIDI data to/from your computer to be distributed to additional MIDI devices.
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S/PDIF IN and OUT – two phono (RCA) sockets carrying two-channel digital audio signals into or out of the Scarlett 18i20 3rd Gen, in S/PDIF format. Note that S/PDIF inputs and outputs are unavailable at 176.4/192 kHz sample rates. Please refer to the Channel Listing tables in the Appendix section for more details.
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AC mains – standard IEC socket.
The Scarlett 18i20 3rd Gen should be connected to AC mains with the supplied AC power cable. Plug the IEC connector into the rear panel IEC socket. When using the Scarlett 18i20 3rd Gen with a computer (i.e., not as a “stand-alone” mixer), we recommend the unit is not turned on until the USB connection has been made.
To connect the Scarlett 18i20 3rd Gen to AC mains, use the provided AC power cable. Insert the IEC connector into the rear panel’s IEC socket. When using the Scarlett 18i20 3rd Gen with a computer (rather than as a “stand-alone” mixer), turn on the device only after connecting the USB cable.
USB Port Types: The Scarlett 18i20 3rd Gen has a single Type C USB 2.0 port (on the rear panel). Once the software installation is complete, connect the Scarlett 18i20 3rd Gen to your computer; if your computer has a Type A USB port, use the Type A-to-Type C USB cable provided with the unit. If your computer has a Type C USB port, please obtain a Type C-to-Type C cable from a computer supplier.
USB Standards: Note that because the Scarlett 18i20 3rd Gen is a USB 2.0 device, the USB connection requires a USB 2.0 compliant port on your computer. It will not operate with USB 1.0/1.1 ports: however, a USB 3.0 port will support a USB 2.0 device.
When the USB cable has been connected, turn the Scarlett 18i20 3rd Gen on with the rear panel power switch.
The Scarlett 18i20 3rd Gen is compatible with any Windows-based DAW that supports ASIO or WDM or any Mac-based DAW that uses Core Audio. After following the Getting Started procedure, you can start using your Scarlett 18i20 3rd Gen with the DAW of your choice.
Please note - your DAW may not automatically select the Scarlett 18i20 3rd Gen as its default I/O device. You must manually select Focusrite USB ASIO as the driver on your DAW’s Audio Setup* page. Please refer to your DAW’s documentation (or Help files) if you are unsure where to select the ASIO/ Core Audio driver. The example below shows the correct configuration in the Ableton Live Lite Preferences panel (Windows version shown).
*Typical name. Terminology may differ between DAWs.
Once the Scarlett 18i20 3rd Gen is set as the preferred Audio Device* in your DAW, all inputs, and outputs appear in your DAW’s Audio I/O preferences. Depending on your DAW, you may need to enable certain inputs or outputs before use.
The two examples below show two inputs and two outputs enabled in Ableton Live's Input and Output Config pages.
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*Typical name. Terminology may differ between DAWs.
Two additional inputs, inputs 9/10 are listed in the Input Config page of your DAW’s I/O Preferences. These are virtual “loopback” inputs within software, not additional physical inputs. You can use Loopback to record DAW tracks from sources within your computer, e.g., from a web browser. Focusrite Control incudes a Loopback 1-2 mix tab, where you can choose which inputs to record.
Full details of how to use the loopback inputs can be found in the Focusrite Control User Guide.
The Scarlett 18i20 3rd Gen is an excellent choice for several different recording and monitoring applications. Some typical configurations are shown below.
This setup shows a typical configuration for recording a group of musicians with DAW software on Mac or PC.
A selection of sources – microphones, guitar, and a keyboard – are shown connected to the Scarlett 18i20 3rd Gen’s inputs. Only Inputs 1 and 2 can be configured to accept instruments directly, so we have chosen to plug the guitar into Input 2. Ensure INST is selected for this input.
The connection to the PC or Mac running DAW software is via the USB cable supplied. This will carry all the input and output signals between the DAW and the Scarlett 18i20 3rd Gen. Once the audio setup is configured in the DAW, each input source will be routed to its own DAW track for recording.
You will frequently hear the term “latency” used in connection with digital audio systems. In the case of the simple DAW recording application described above, latency will be the time it takes for your input signals to pass through your computer and audio software, and back out again via your audio interface. While not an issue for most simple recording situations, under some circumstances, latency can be a problem for a performer who wishes to record while monitoring their input signals. This might be the case if you need to increase the size of your DAW’s recording buffer, which could be necessary when you record overdubs on a particularly large project using many DAW tracks, software instruments and FX plug-ins. Common symptoms of a buffer setting too low could be glitching audio (clicks and pops), or a particularly high CPU load within your DAW (most DAWs have a CPU monitoring function). Most DAWs will allow you to adjust buffer size from their Audio Preferences* control page.
The Scarlett 18i20 3rd Gen, with Focusrite Control, allows “zero latency monitoring”, which overcomes this problem. You can route your input signals directly to the Scarlett 18i20 3rd Gen’s headphone outputs. This enables the musicians to hear themselves with ultra-low latency – i.e., effectively in “real time” – along with the computer playback. The input signals to the computer are not affected in any way by this setting. However, note that any effects being added to the live instruments by software plug-ins will not be heard in the headphones, although the FX will still be present on the recording.
In the example, each of the band members is receiving his/her own monitor mix, because they each have their “own” Scarlett 18i20 3rd Gen output. Focusrite Control lets you define up to eight separate mixes, and these mixes may include previously recorded DAW tracks as well the current input signals.
When using Direct Monitoring, ensure your DAW software is not set to route any inputs (what you are currently recording) to any outputs. If it is, the musicians will hear themselves “twice”, with one signal audibly delayed as an echo.
The 1/4” jack MAIN outputs on the rear panel (Line Outputs 1 and 2) will normally be used to drive your primary monitoring speakers. Active monitors incorporate internal amplifiers with a volume control, and may be connected directly. Passive loudspeakers will require a separate stereo amplifier; the rear panel outputs should be connected to the amplifier’s inputs.
Connecting active speakers:
Connecting passive speakers with a stereo amplifier:
All the line output connectors are 3-pole (TRS) ¼” (6.35 mm) jack sockets, and are electronically balanced. Typical consumer (hi-fi) amplifiers and small powered monitors will probably have unbalanced inputs, either on phono (RCA) sockets, or via a 3.5 mm 3-pole jack plug intended for direct connection to a computer. In either case, use a cable with jack plugs at one end.
Professional active monitors and professional power amplifiers will generally have balanced inputs.
When mixing, you might want to use several pairs of additional speakers (mid-field. near-field, etc.) to check how well your mix translates to other types of speaker. You can connect additional pairs of speakers to other pairs of Line Outputs (e.g., near-fields to Line Outputs 3 and 4, mid-fields to Line Outputs 5 and 6) and switch between them in Focusrite Control. Scarlett 18i20 3rd Gen’s ALT function (see below) has been included to make using a second pair of monitors simple.
Caution
You run the risk of creating an audio feedback loop if loudspeakers are active at the same time as a microphone! We recommend you always turn off (or turn down) monitoring loudspeakers while recording, and use headphones when overdubbing.
The Scarlett 18i20 3rd Gen’s ALT function makes adding a second pair of monitors easy: connect the second pair to LINE OUTPUTS 3 and 4. After enabling Speaker Switching in Focusrite Control, you can switch between your main monitors and the secondary pair by clicking on the front panel or on-screen MAIN and ALT buttons. When ALT is active, the main mix output will be fed to the LINE OUTPUTS 3 and 4 instead of 1 and 2, and the green ALT LED will light to confirm this.
In the example below, we have shown passive speakers with a separate power amplifier as the main monitors and active speakers as the secondary pair, but of course, any type of monitors you prefer may be used in either case.
Because the Scarlett 18i20 3rd Gen is equipped with ten line outputs, it is ideally suited for use when working in multichannel sound formats – LCRS, 5.1 surround or 7.1 surround, for example.
To route each channel to the correct output you will need to route the DAW outputs to the Line Outputs in Focusrite Control (e.g. DAW Output 1 > Line Output 1, DAW Output 2 > Line Output 2, etc.).
The example below shows how you connect the six loudspeakers to the Scarlett 18i20 3rd Gen in a 5.1 surround monitoring arrangement.
Windows users:
On Windows, surround sound can be used in both software supporting multichannel ASIO and non- ASIO applications (using our driver). In most cases this will be your DAW, and in general, DAWs capable of mixing in surround allow you to set the speaker mapping up in the DAW’s Audio Output Preferences or I/O Settings page.
Please see the user guide (or Help files) for your DAW for guidance on setting up the outputs for surround mixing with the speaker configuration you wish to use.
To set up surround sound in non-ASIO applications:
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Right-Click on the Focusrite Notifier icon in your Windows taskbar and click to open Windows Sound Panel.
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Click the Focusrite device listed in the Playback tab to highlight it.
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Click the Configure button.
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Select a multichannel format, the option you choose depends on how you are using your Scarlett.
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Go to Focusrite Control and click, File > Presets > Direct Routing, to set up one-to-one routing.
Mac users:
On Macs, surround sound configuration can be done from all applications that support multichannel audio (DAWs & regular macOS Applications). To do this, go to: Applications > Utilities > Audio MIDI Setup > Scarlett 18i20 3rd Gen > Configure Speakers > Configuration > Select the desired configuration.
In addition to the eight analogue inputs, the Scarlett 18i20 3rd Gen has two OPTICAL IN ADAT input ports. These provide eight additional audio inputs at sample rates up to 96 kHz. The optical inputs are disabled at sample rates of 176.4/192 kHz.
Using a separate 8-channel microphone preamplifier equipped with an ADAT output – such as the Focusrite Scarlett OctoPre – provides a simple and excellent method of expanding the Scarlett 18i20 3rd Gen’s input capability.
At 44.1/48 kHz, the Scarlett OctoPre’s ADAT OUT 1-8 port is connected to the Scarlett 18i20 3rd Gen OPTICAL IN port 48 – 1-8 with a single TOSLINK optical cable. To synchronise the devices over ADAT, set the clock source of the Scarlett OctoPre to Internal and Scarlett 18i20 3rd Gen (via Focusrite Control) to ADAT. Alternatively, stable clock synchronisation may be achieved by connecting the Scarlett 18i20 3rd Gen’s WORD CLOCK OUT to the Scarlett OctoPre’s WORD CLOCK IN and setting the Scarlett OctoPre to use Word Clock as its clock source. Set the Scarlett 18i20 3rd Gen’s clock source in Focusrite Control to Internal.
When connecting two digital devices, always ensure both are set to the same sample rate.
You can route the additional ADAT inputs using Focusrite Control in exactly the same way as the other inputs. The additional inputs can form part of any musician’s headphone mix, as required.
When working at 88.2/96 kHz, add a second TOSLINK optical cable between the Scarlett OctoPre’s ADAT OUT 5-8 port and the 18i20’s OPTICAL IN 5-8 – 96 port. At the higher sample rate, this second link will carry Channels 5-8, while the other link (described above) will carry Channels 1 to 4.
If you have a digital-to-analogue converter, you can use the 18i20’s OPTICAL OUT ADAT ports in the opposite way; for example, additional outputs from your DAW can be converted into the analogue domain to use an external hardware mixing console to mix down many DAW tracks. At
44.1/48 kHz sample rate, the right-hand OPTICAL OUT port carries Channels 1 to 8, while at 88.2/96 kHz, the right-hand port carries Channels 1 to 4 and the left-hand port Channels 5 to 8.
The Scarlett 18i20 3rd Gen has the ability to store a mix configuration defined in Focusrite Control within the hardware. This feature lets you configure it – for example, as an on-stage keyboard mixer – using your computer, and upload the configuration to the device itself. You can use the Scarlett 18i20 3rd Gen as a simple local mixer as part of your keyboard rig to control the overall mix of multiple keyboards.
In the example illustrated, three stereo keyboards are connected to the rear panel inputs of the Scarlett 18i20 3rd Gen; Outputs 3 and 4 go to the main PA system. The performer can adjust the gain for the individual keyboards from the front panel; he/she can also adjust the overall level of the keyboard mix.
Using the digital connections on the Scarlett 18i20 3rd Gen 3rd gen it is possible to use it as a two-channel (S/PDIF) or up to eight-channel (ADAT) standalone preamp.
You can connect input sources to any of the inputs on the Scarlett (microphone, line or inst) and using Focusrite Control you can route the analogue inputs directly to the S/PDIF or ADAT outputs. Then you can connect the digital output you are using to the S/PDIF or ADAT input on another interface to expand that interface’s channel count. For example a second Scarlett 18i20 3rd Gen’s ADAT input port.