Specifications

HD I/O Guide40
For example, to have 12 dB of headroom above
0 VU with the HD I/O, you must align the in-
coming 0 VU 1kHz tone to a level of –12 dBFS.
For 18 dB of headroom, you would align it to
–18 dBFS. (Since it is assumed that you are us-
ing the HD I/O with a +4 dBu device or console,
a 0 VU signal level coming out of the device or
console is actually equivalent to a nominal
+4 dBu level signal.)
Calibrating the HD I/O
To calibrate your HD I/O, use one of the HD I/O
calibration sessions included with Pro Tools
(located in the Pro Tools Utilities/Calibration
Mode Session/HD IO Calibration Session
folder). You can use these sessions as is and
change the input and output assignments for
more HD I/O channels or use it as a template to
make your own calibration session.
The following instructions show how to create a
calibration session from scratch.
To create a session for calibrating your HD I/O:
1 Launch Pro Tools and create a new session.
2 Choose Setup > Preferences and click the Op-
eration
tab.
3 Enter the desired Calibration Reference Level
value in dB. A level of –18 dB is typical. (It is not
necessary to type a minus sign here.)
4 Click OK.
5 Create a new mono audio track by choosing
Track > New.
6 Insert the Signal Generator plug-in on the
track.
7 Set the Signal Generator plug-in output level.
This should be the same value you entered as the
Calibration Reference Level (such as –18 dB).
8 Set the Signal Generator frequency to 1000 Hz.
1000 Hz is typical, but any frequency will work.
Other typical values are 250 Hz and 500 Hz.
9 Set the Signal Generator signal waveform to
Sine.
10 Route the track’s output to Bus 1. In the cali-
bration template, Bus 1 has been renamed to “1k
Tone.”
11 Create a mono Auxiliary Input track for each
HD I/O output you want to calibrate. Set the out-
put assignment for each of these Auxiliary In-
puts to its respective I/O output.
12 Set the input of each Auxiliary Input track to
Bus 1, or 1k Tone for the template session.
If your system includes one or more EUCON
controllers, be sure to disable “Auto-bank to
selected track” in EuControl software before
enabling Pro Tools Calibration Mode to en-
sure that faders remain silent. To make sure
“Auto-bank to select track” is not enabled,
open the EuControl Settings window, click
to go to the General tab, and verify the set-
ting is not enabled. If necessary, click to dis-
able “Auto-bank to selected track.” After ex-
iting Calibration Mode, be sure to re-enable
the “Auto-bank to selected track” setting (if
necessary).
Turn down your monitoring system before
beginning calibration. The Signal Genera-
tor plug-in emits a continuous signal when
inserted on a track.