Specifications
Chapter 3: Installation Overview 23
Input Trims
The Input Trims below the two DB–25 connec-
tors on the Analog In card are used to store two
different calibration settings (A and B) for each
channel.
These two adjustable Input Trims are for pre-
cisely calibrating and switching between a
choice of independently adjustable headroom
settings for each channel. You can adjust each
Input Trim by hand with a small screwdriver.
Choose between your A and B Input Trim set-
tings from within Pro Tools in the Hardware
Setup dialog on the Analog In tab.
For example, you could use the A trims for the
+4 dBu port, and use the B trims for –10. Or, use
A and B to maintain two different trims for any
signal input port (+4 dBu or –10 dBV).
However, if you do are not using the –10 dBV in-
put connector, the B trims can be used to store
an alternate set of headroom values for the
+4 dBu inputs. Once set, you can switch be-
tween the different trim headroom values for
the same input level in the Analog Input tab in
Hardware Setup.
See also “+4 dBu Balanced” on page 5 and
“–10 dBV Balanced” on page 5.
Soft Clip Limiting
The Soft Clip limiter attenuates the incoming
analog signal, providing extra protection from
temporary clipping transients that can cause
digital distortion when they exceed the maxi-
mum input of the unit.
With Soft Clip enabled, 192 I/O supports an ad-
ditional 4 dB of headroom by rounding off the
top 4 dB to the clip point. This is useful for elim-
inating that stray transient or emulating analog
tape saturation.
To enable Soft Clip limiting:
1 Launch Pro Tools.
2 Choose Setups > Hardware Setup in Pro Tools.
3 Click on the Analog In tab.
4 Select Soft Clip for each channel to which you
want to provide this protection.
Synchronization Mode and
Clock Source
The 192 I/O lets you resolve your Pro Tools|HD
system to most digital clock references in use in
today's complex, multi-unit production envi-
ronments.
The Hardware Setup dialog lets you specify
among digital input sources and select a clock
source.
Choices for Clock Source vary depending on
Sample Rate and Digital Format that is enabled
(AES/EBU, S/PDIF, or Optical S/PDIF).
Pro Tools|HD and the 192 I/O give you multiple
clock reference choices at all sample rates and
digital format settings.