Avid Technology HD I/O User Manual

Pro Tools | HD I/O Guide30
Using Input Trims
Input Trims
The Input Trims below the two DB-25 connectors
on the HD I/O AD Expansion card are used to store
a calibration settings for each channel. These ad-
justable Input Trims are for precisely calibrating
the adjustable headroom settings for each channel.
You can adjust each Input Trim by hand with a
small screwdriver.
About Input Operating Levels
Check the manufacturer’s documentation for your
mixer, power amplifier, or effects processor to see
if it operates more comfortably at line level, in
which case consider setting the HD I/O to operate
at –10 dBV line levels and adjusting the Input
Trims.
Consider the following when connecting a mixer:
 If your mixer cannot handle more than 1.5V
(RMS) inputs at +4 dBu, then you should set the
HD I/O to operate at –10 dBV line level.
 If your mixer can handle up to 15.5V (RMS) in-
puts, or has pads or attenuators on its inputs, then
you can use the +4 dBu setting on the HD I/O.
 HD I/O is calibrated at the factory for 18 dB
headroom at the +4 dBu setting.
Most manuals contain device input specifications,
including whether or not there are pads or attenua-
tors. Refer to the manufacturer’s documentation
for your mixer or power amplifier for more infor-
mation.
Input Trims
If you want to switch the input levels of the
HD I/O from +4 dBu to –10 dBV, you can ac-
cess these parameters on a channel-by-chan-
nel basis in the Hardware Setup dialog (see
“Hardware Setup” on page 21).

Avid Technology HD I/O Specifications

General

Brand	Avid Technology
Model	HD I/O
Category	Accessories
Language	English