Focusrite’s Scarlett 18i20 4th Gen finally brings serious studio reputation to the range£629.99/$749.99, focusrite.com
The fourth generation of Focusrite’s eternally popular Scarlett audio interfaces broke cover in late 2023 with the launch of the Solo, 2i2 and 4i4. Since then, those requiring higher input/output counts have had to sit tight whilst Focusrite busied itself updating the larger Scarlett units.

READ MORE: The Scarlett 4th Gen story: Focusrite’s journey from George Martin’s AIR to bedroom studios everywhere

That hiatus has now ended with the launch of the 4th Gen Scarlett 16i16, 18i16 and, most pertinently for this review, the 18i20.
The only difference between the two new i16 models lies in the number of preamp-equipped input channels they offer: 16i16 has two whilst the 18i16 has four. Their design and desktop enclosures make them appear essentially as beefed-up versions of the 4i4, albeit with a more generous analogue in/out count and the inclusion of S/PDIF and ADAT digital connections.
We could easily fill this page talking about these tempting offerings, but it’s the flagship of the Scarlett range, the 18i20, that interests us especially.
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How does the 18i20 4th Gen differ from the rest of the Scarlett range?
As with previous Scarlett generations, the 18i20 immediately stands out as the only member of the range packed into a rackmount case (the lugs can be removed if not needed) and with an internal power supply. The updated version features a less cluttered control panel than the 3rd Gen, and this makes the new hardware look sleeker while also improving accessibility for users with physical restrictions.
Unlike the other Scarletts, which only provide preamps on some of their analogue input channels, all eight of 18i20’s analogue inputs are preamp-equipped, and so all can handle microphone as well as line signals. The XLR/jack combination sockets for these inputs are mounted on the rear of the unit, but the first two are doubled-up on the front panel, from where they can also accept instrument signals.
Connecting anything to one of the front panel inputs disables the corresponding rear connector. This allows the interface to be installed in a rack and fully integrated into the studio’s cabling whilst retaining the ability to quickly hook-up a guitar or other signal directly to the front of the interface. Nice!
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All of 18i20’s analogue output pairs are served by their own digital-to-analogue converter (the same is also true of the new i16 units), and so the eight rear-facing line outputs and two front-mounted headphone outputs can each be routed from any of the interface’s impressive 42 internal busses or six internal mixes. There’s loads of scope for creating multiple cue mixes and for routing signals to external effects and processors.
​​Outputs 1 and 2 are assigned as main monitor outputs, although you can send any of the internal buses or mixes to this monitor out. If the speaker switching option is enabled, outs 3 and 4 carry the same feed for driving an alternate pair of monitors. Monitor sets can then be switched from the interface’s front panel or from the Control 2 software. There are also Dim and Mute buttons, and this pro-grade monitoring setup is topped-off with a talkback button and built-in talkback mic.
18i20 also sports stereo digital in/outs via S/PDIF, and two pairs of ADAT ports. In an ideal world these would provide 16 additional channels at up-to 48kHz, but 18i20 maxes-out at eight. On the plus side, the dual ports support that full eight channels at 96kHz.
ADAT connectivity integrates seamlessly with an external 8-way preamp such as Focusrite’s OctoPre Dynamic. Coupling one with an 18i20 adds cost, but a total spend of £1,300-ish is phenomenal value for a system offering 16 preamp-driven analogue inputs and 16 independent line outputs.
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What’s new with the Scarlett preamps?
The Scarlett 4th Gen interfaces feature an updated low-noise preamp design that is accurate and provides a generous 69dB of gain. This is all well and good, but not unusually so in today’s market. Nevertheless, the new Scarlett preamps do have features that set them apart.
Air mode engages a presence peak EQ curve intended to mimic the response of Focusrite’s classic ISA console preamps. The curve has been modified for the 4th Gen hardware, giving it a slightly sweeter tone that’s more widely useful. There is also now a second Air mode that adds a gentle high-frequency saturation to the presence peak, injecting sparkle and liveliness to benefit a diverse range of sources. It’s especially effective when applied to a guitar plugged into an instrument input, giving front-end punch and drive to add life into amp simulation plugins.
Preamp gain is now controlled digitally, either via the hardware’s Input dial, or via Control 2 running on a computer. A game-changing feature for self-recording musicians is that the Scarlett hardware can also be controlled from any iOS or Android device connected to the same network as the computer. Setup is simple, and it allows you to configure inputs, keep an eye on levels, and set up monitor mixes from anywhere in the studio.
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Digital gain control also lies behind new Auto Gain and Clip Guard features. The former analyses a few seconds of the input signal and then sets an appropriate preamp gain. The system tends to be a bit more conservative than an experienced recording engineer, but it is helpful and reliable nonetheless. The ability to set the gain of all channels simultaneously, in a few seconds, is a huge timesaver when recording a full band or drum kit.
When enabled, Clip Guard ensures you will never have an errant clip or overload ruin an otherwise perfect take. It does this by cutting 6dB from the analogue gain stage and adding it back in digitally. If the incoming signal exceeds -6dB, Clip Guard instantly reduces the digital gain stage accordingly and then maintains that new level. Rather than a nasty digital crunch, resulting level dips can be fixed easily in your DAW.
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How does the Scarlett 18i20 4th Gen stand apart from the competition?
18i20 delivers improved audio accuracy and dynamic range compared to the previous iteration thanks to being loaded with the same converters used in Focusrite’s high-end RedNet hardware. This ensures highly accurate audio capture and playback, as one would expect from Focusrite, but such unimpeachable specs aren’t unusual from today’s crop of audio interfaces.
What differentiates the 18i20 – and indeed the entire Scarlett 4th Gen range – is how easy it makes the process of configuring inputs and capturing performances, especially for self-recording producers and musicians.
The Hitmaker software package included with all Scarlett units also eases things along, with DAWs and tools to get new producers up and running straight away, as well as top-grade plugins and instruments that will be welcomed by more seasoned users.
On the downside, heavy inflation has had an inevitable impact on the price of the 4th Gen 18i20, with an uplift of £180 compared to the launch price of the 3rd Gen. Nevertheless, Focusrite is offering a lot of interfaces, packed with pro features, for what is still a reasonable price. Whether you’re setting up an entirely new rig or upgrading an existing one, 18i20 is an investment that is sure to pay off.

Key features

USB-2 audio interface with USB-C socket
USB-C cable and USB-C to USB-A converter included
Mains powered
2 mic/line/instrument inputs
6 further mic/line inputs
8 line outputs and
2 independent headphone outputs
ADAT (S/MUX) and stereo S/PDIF digital I/O
MIDI in/out
Built-in talkback mic
Word Clock output

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