Studio Technologies 68 V.1 - Manual (Page 16)

Issue 2, June 1999 Model 68/69 User Guide
Page 16 Studio Technologies, Inc.
for Surround
Level Calibration
Sixteen multi-turn trim potentiometers
grace the front panel of the Model 68
Central Controller. Taking time to carefully
adjust the trim pots will ensure that accu-
rate monitoring can take place. Each trim
pot allows an adjustment range of nomi-
nally ±2dB, which is spread over the trim
pot’s 15 turns. Calibrating the surround
and stereo input levels to within one-tenth
of a dB of the desired point is easily
performed.
The monitor outputs are used as the
measuring point when adjusting the trim
pots. A laboratory-grade audio level meter,
or equivalent, is required for accurate
calibration. In addition, the audio sources
connected to the inputs must be set to
generate audio signals at their nominal
operating level.
Procedure
This procedure will ensure that the sur-
round and stereo inputs are level matched
against each other. The trim pots will be
adjusted in groups corresponding to their
associated input sources.
1. Begin by turning the audio amplifiers
or amplified speakers to their off state.
This will protect the operator’s ears
from possible damage.
2. Rotate the level control on the Model
69 to the fully clockwise (maximum)
position.
3. On the Model 68, connect the audio
level meter to the left channel of the
monitor output.
4. Using the Model 69 Control console,
select input 1 (Surround A) as the
audio source.
5. Confirm that the audio source’s left
channel is generating a steady signal
at precisely its reference level. (For
this procedure, it is assumed to be
+4dBu.)
6. Observing the level meter, adjust input
1, trim pot L, to give a precise +4dBu
level at monitor output L.
7. Disconnect the level meter from the
left channel of the monitor output.
8. Repeat steps 3-7 for the center, right,
left surround, right surround, and
subwoofer channels of input 1
(Surround A).
9. Repeat steps 3-8 for inputs 2-4 (Sur-
round B, Stereo A, and Stereo B).
Obviously, the stereo inputs have only
left and right inputs, requiring only that
two trim pots be adjusted for each.
10. Rotate the level control on the Model
69 to the fully counterclockwise (mini-
mum) position.
11. After ensuring that the Model 69’s level
control is set to minimum, return the
AC mains switches on the power
amps or amplified speakers to their
on position.
Model 69 Operating
Parameters
Many StudioComm functions can be
configured to meet the exact needs of your
installation. Here’s an overview of what
you can configure:
• Input channels active for each of the
four inputs
• Monitor output channels active
• Local L/R Bypass