Appendix C: 192 I/O Calibration Mode Instructions 23
appendix c
192 I/O Calibration Mode Instructions
Before you use the 192 I/O audio interface, you
may want to calibrate its input and output levels
to the level of your mixing console.
The 192 I/O has +4 dBu and –10 dB(V) inputs,
and +4 dBu outputs, each with their own trim
pots for proper calibration.
The 192 I/O is factory-calibrated so that its
+4 dBu input operating level is set for 18 dB
headroom above +4 dBu (maximum input/out-
put +22 dBu).
If you need to recalibrate your 192 I/O or other
components of your studio, you can use the
alignment procedure described in this chapter.
About Calibration
Calibrating levels on a digital recording device is
different from calibrating levels on an analog re-
cording device. Unlike analog devices, most dig-
ital devices do not have a standard “0 VU” level
setting that corresponds to nominal input and
output levels. Instead, with an interface such as
the 192 I/O, the meters are calibrated in decibels
below peak or dBFS (dB full scale)—digital clip-
ping level.
Headroom
The concept of headroom is slightly different for
analog and digital devices.
Analog Most analog devices allow for a certain
amount of headroom above 0 VU. If you send a
signal above 0 VU to an analog recorder, you
still have a margin of headroom, and if tape sat-
uration occurs, it does so fairly gracefully, giving
the audio a compressed sound that some find
desirable.
Digital Digital devices, on the other hand, do
not allow for signals that exceed the dynamic
range of the input or dBFS (dB full scale). When
a signal exceeds the maximum input level for a
digital device, clipping occurs, causing digital
distortion, which is harsh and usually undesir-
able.
The Calibration Process
Analog To calibrate the input level of an analog
device to a mixing console’s output level, you
would typically send a 1 kHz tone at 0 VU from
the console to the analog deck and align the re-
cording deck’s meters to read 0 VU.
To Next Page
Loading...
Need help?
General
