Specifications

Appendix C: HD I/O Calibration Mode Instructions 39
16 Adjust the I/O output level trim pot with a
small, flat-head screwdriver to align the outputs
to read “0 VU” on the external VU meter.
We
recommend using a tweaker tool with a recessed
flat-head surrounded by a plastic tube to hold
the trim pot. Tweakers can usually be found at
electronic supply stores.
To calibrate the HD I/O inputs:
1 Connect the HD I/O outputs to a bank of
HD I/O inputs by doing either of the following:
• Use a DB-25 to DB-25 straight through ca-
ble.
• Interconnect the XLR ends of DB-25-to-
XLR together.
2 In Pro Tools, select Options > 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 (default is
–18 dB).
3 Adjust the HD I/O input level trim pots with
the same small flat-head screwdriver or tweaker.
It is best to calibrate the inputs with the back of
the HD I/O facing you and the Pro Tools screen
well in sight. If you cannot see the Pro Tools
screen, consider asking another person to assist
you with the input calibration. When the level
is properly matched, the track name will stop
flashing and the peak volume indicator will in-
dicate your headroom value (the default is
“–18.0”).
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 ap-
pear lit (blue). In this case, trim the I/O in-
put level down.
• When the incoming level is lower than the
reference level the up arrow will appear lit
(red). In this case, trim the 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.
Above the fader is a peak volume indicator. This
indicator will show the dB level above and be-
low your chosen headroom value. If the peak in-
dicator is showing –19.1, you are –1.1 dB below
a headroom value of –18 dB. If the display is
showing –16.5, you are +1.5 dB above your
headroom value of –18 dB.
4 When you have finished, deselect Options >
Calibration Mode.