Installation guide

Chapter 7: Calibrating the 888/24 I/O 55
14 Create an additional mono Auxiliary Input
track for each 888/24 I/O input you want to cal-
ibrate. Set the input assignment for each of
these Auxiliary Inputs to its respective
888/24 I/O input. Then set the output of each of
these Auxiliary Inputs to an unused bus pair (for
example Bus 31–32) so that feedback doesn’t oc-
cur when monitoring main outputs 1–2.
15 Connect an external VU meter to each of the
888/24 I/O outputs in turn. (One at a time as
you calibrate.)
16 Set all Pro Tools track faders to their default
of 0 dB by Shift-Option-clicking each fader in
the session.
17 Adjust the 888/24 I/O output level trim pots
with a Phillips screwdriver to align the outputs
to read “0 VU” on the external VU meter.
18 Connect each output of the 888/24 I/O di-
rectly to its input. Connect channel 1 output to
channel 1 input, and so on for each channel.
19 In Pro Tools, select Operations > Calibration
Mode.
The names of all uncalibrated tracks begin to
flash. In addition, the track volume indicator of
each Auxiliary Input track receiving an external
input signal now displays the reference level
coming from the calibrated output.
20 Adjust the 888/24 I/O input level trim pots
with a Phillips screwdriver to align the inputs to
match the reference level. When the level is
properly matched, the track name will stop
flashing.
The Automatch indicator arrows on each track
show the direction of adjustment required for
alignment:
◆ When the incoming level is higher than the
reference level, the down arrow will appear lit
(blue). In this case, trim the 888/24 I/O input
level down.
◆ When the incoming level is lower than the
reference level the up arrow will appear lit (red).
In this case, trim the 888/24 I/O input level up.
When you have properly aligned the incoming
peak signal levels to match the calibration refer-
ence level, both Automatch indicator arrows
will light: the up arrow red and the down arrow
blue.
21 When you have finished, deselect Opera-
tions > Calibration Mode.
Calibrating a System with Both
888/24 I/O and 882/20 I/O Audio
Interfaces
The 888/24 I/O is factory preset with 18 dB of
headroom in its +4 dB line level operating
mode. The 882/20 I/O, however, is fixed at
14 dB of headroom and its inputs are not adjust-
able.
When setting up an 882/20 I/O (particularly in
systems using a combination of the 882/20 I/O
and 888/24 I/O), make sure that you use a head-
room setting of –14 dB for your system. This
helps ensure that recorded audio files have the
same relative levels regardless of which interface
they are recorded with.
TDM_Install.book Page 55 Saturday, January 13, 2001 9:35 PM