Focusrite Scarlett 18i20 USB-C Audio/MIDI Interface (3rd Generation) User Manual
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Using the ADAT connection
In addition to the eight analogue inputs, the Scarlett 18i20 has two OPTICAL IN ADAT input ports
which can provide an additional eight audio inputs at sample rates up to 96 kHz. Note that the optical
input is disabled when sample rates of 176.4/192 kHz are in use.
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’s input capability.
Computer
running DAW
and
Focusrite
Control
Inputs 1 & 2 on front panel
Optical ADAT connection (TOSLINK)
Additional TOSlink connection required at 96 kHz
Wordclock link
Inputs 1 & 2 on front panel
Up to 16 Mic/Line Sour
ce
s
Scarlett OctoPre
8ch Mic Amp
At 44.1/48 kHz, the Scarlett OctoPre’s ADAT OUT 1-8 port is connected to the Scarlett 18i20 OPTICAL
IN port marked 48 – 1-8 with a single TOSLINK optical cable. To synchronise the two devices over
ADAT, set the clock source of the Scarlett OctoPre to Internal and that of the Scarlett 18i20 (via
Focusrite Control) to
ADAT
. Alternatively, stable clock synchronisation may be achieved by connecting
the Scarlett 18i20’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. In this case, set the Scarlett 18i20’s clock
source in Focusrite Control to
Internal
.
TIP: When interconnecting two digital devices by any method, always ensure that both are set
to the same sample rate.
The additional inputs realised by use of the ADAT port may be routed using Focusrite Control in
exactly the same manner 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.