MOTU 1248 User Manual page 52

provides individual preamp gain, pad and 48V
phantom power. (Phantom power is supplied to the
XLR connector only.) Use these general guidelines
for the 48V phantom power, pad and gain settings
on these combo input jacks:
Input
Condenser mic
Dynamic mic
Guitar
-10 dBV Line level via TRS
-10 dBV Line level via XLR
+4 dBu Line level (XLR
only)
V-Limit™
Each 8M mic input is individually equipped with
V-Limit (page 18), which help prevent digital
clipping from overloaded input signals. For details,
see "8M mic/guitar input meters with V-Limit™
compressor" on page 69.
Soft Clip™
Additional or alternative protection can be applied
individually to 8M mic/guitar inputs by enabling
Soft Clip (page 18). When enabled, Soft Clip
engages just before clipping occurs and helps
further reduce perceptible distortion.
TRS quarter-inch analog inputs and outputs
Quarter-inch analog inputs and outputs are
balanced (TRS) connectors that can also accept an
unbalanced plug.
☛
Quarter-inch analog outputs are not
cross-coupled. Therefore, when connecting them
to an unbalanced input, use a TRS plug with the
ring disconnected. Not floating the negative
terminal will short it to the sleeve ground and
cause distortion.
52
48V Pad Gain
On As needed As needed
Off As needed As needed
n/a n/a As needed
n/a n/a As needed
Off -20 dB +12dB
Off -20 dB Zero
Dedicated main outs and monitor outs
Like all I/O on the 1248, the main outputs and
monitor outputs operate as independent pairs
(they don't share signal with any other output
pair). In a standard studio configuration, these
outputs are intended for pairs of studio monitors,
but they can also be used as regular outputs for any
purpose. With adjustable converter trim, they
support a wide range of industry-standard
reference levels. Volume is controlled by the MAIN
and MON (Monitor) volume knobs on the front
panel.
TRS quarter-inch analog trims
All quarter-inch analog inputs and outputs can be
trimmed. This allows them to support a variety of
standards, including EBU-R68, SMPTE RP-155,
+4dBu, -10dBV, 2vRMS, 1vRMS.
Quarter-inch analog inputs are equipped with
high-quality, digitally controlled analog trim that
provides a range from -96 to +22 dB in 1dB steps.
Quarter-inch outputs can be trimmed in the DAC
itself. Range is 24 dB. The Main Outs, Monitor
Outs and Phones provide full trim range from 0 dB
to -∞ (-127).
Trim controls are most easily accessed in the web
app. See "Device tab" on page 18. Trim settings can
also be accessed in the LCD menu.
Optical
Your MOTU audio interface provides two banks of
ADAT optical ("lightpipe") connectors. Each bank
provides an input and output connector. Together,
they provide 16 channels of ADAT optical digital
I/O at 44.1 or 48 kHz, or 8 channels at 88.2 or 96
kHz. The optical ports are disabled when the
interface is operating at a 176.4 or 192 kHz. At the
high sample rates (88.2 or 96 kHz), 4-channel
SMUX operation supports two modes (item #23
on page 21):
H A R D W A R E I N S T A L L A T I O N