Orban OPTIMOD-FM 8600, Operating Manual

Page: 88 / 397

2-28
INSTALLATION ORBAN MODEL 8600
This setup maximizes the 8600’s signal-to-noise ratio. If the clip level is set too
low, the 8600’s analog-to-digital converters will overload and distort on program
peaks. If the clip level is set too high, the signal-to-noise ratio will suffer. Use care
and attention in setting this adjustment.
We have found that the single most common reason for distorted sound on-air in
other Orban digital processors is maladjustment of the
C
LIP
L
EVEL
control, such
that the A/D converter is clipping and distorting. This will always be clearly indi-
cated by the
I
NPUT
meters’ going into the red part of their scale.
If you are adjusting the 8600 during normal programming and cannot interrupt
or distort the program to play program material from your studio at a much
higher level than normal, follow the directions to:
•
Calibrate while on air with normal programming: step (A) on page 2-28.
If you are able to interrupt or distort normal programming, you can achieve cali-
bration that is more precise. Follow the directions to:
•
Calibrate with unprocessed audio: step (B), page 2-28, or
•
Calibrate with a Studio Level Control System that has a built-in 100% Calibra-
tion Tone, such as the Orban 6300, 8200ST-Studio Level Controller or 4000
Transmission Limiter: step (C), page 2-29, or
•
Calibrate with an Orban 464A Co-Operator: step (D), page 2-29, or
•
Calibrate with an Orban 1100 or 1101 OPTIMOD-PC
as appropriate.
Note that in this step, you are calibrating to the absolute peak level; this is quite
different from the maximum peak indication of the studio meters.
A) Calibrate with program material and normal programming levels.
[Skip this step if you are calibrating in another manner.]
a) Adjust the
C
LIP
L
EVEL
so that program peaks indicate approximately –15 dB
on the input meters.
Observe the meters on the 8600 screen for a long period; be sure to ob-
serve live announcer voice. If this setting is misadjusted, distortion will re-
sult.
0 dB indicates input clipping on the 8600. These meters should never
peak as high as 0 dB with program material; always leave a safety margin
of headroom.
B) Calibrate with program material and worst-case programming levels (best
method):
[Skip this step if you are calibrating in another manner.]
a) Play program material from your studio at a much higher level than nor-
mal—turn the faders up all the way!
This will usually produce the highest peak level output that your system
can produce.