Studio Technologies 591 - Manual (Page 15)

Issue 1, September 1999 Model 58/591 User Guide
Page 18 Studio Technologies, Inc.
in where the trim pots are located in the
circuitry, and why the meter outputs are
specified as a measurement point, should
refer to the Model 58 Block Diagram,
available from Studio Technologies, Inc.
Main Input Trim Pots
This first procedure will ensure that the
Model 58 main inputs are level matched
against each other. It is assumed that
calibrated metering devices are not al-
ready connected to the meter outputs.
1. On the Model 58, connect the audio
level meter to meter output 1.
2. Using the Model 591 Control console,
select main input 1 to be routed to the
left monitor output. Be certain that
inserts 1 and 2 are not enabled. En-
able the mute all function, ensuring
that you won’t have to hear a steady
tone during the entire procedure!
3. Confirm that the audio source con-
nected to main input 1 is generating a
steady signal at precisely its reference
level. (This is assumed to be nominally
+4dBu.)
4. Observing the level meter, adjust main
input trim pot 1 to give a +4dBu level
at meter output 1.
5. Repeat steps 1-4 for main inputs 2, 3,
and 4.
Insert Return Trim Pots
Describing the calibration process for the
insert returns is a bit more difficult as the
exact implementation of the insert sections
is dependent upon the specific installation.
The goal is to have no unwanted level
change to occur when switching an insert
section between disabled and enabled.
Note that the insert sends are not cali-
brated for a precise +4dBu nominal level.
Trim pots on the insert returns allow level
inaccuracies in the insert sends, as well as
the connected device’s input and outputs,
to be accounted for.
The following procedure would be appro-
priate when an insert section is configured
to place another device in the audio path,
replacing the original. This procedure
assumes that main input calibration has
already been performed. It is also as-
sumed that calibrated metering devices
are not permanently connected to the
meter outputs.
1. On the Model 58, connect the audio
level meter to meter output 1.
2. Using the Model 591 Control console,
select main input 1 to be routed to the
left and right monitor outputs. Confirm
that inserts 1 and 2 are disabled.
Enable the mute all function, ensuring
that you won’t have to hear a steady
tone during the entire procedure!
3. Confirm that the audio source con-
nected to main input 1 is generating a
steady signal at precisely its reference
level.
4. Observing the level meter, confirm that
the output level is exactly +4dBu. (If
this is not the case, the main input trim
pot must be re-calibrated.)
5. Using the Model 591 Control Console,
enable insert 1.
6. Observing the level meter, adjust
the trim pot associated with insert 1,
return 1 to give a +4dBu level at
meter output 1.
7. Repeat steps 4, 5, and 6 for insert 1,
return 2.