Studio Technologies 230 2014 - Manual (Page 34)

Issue 9, November 2014 Model 230 User Guide
Page 34 Studio Technologies, Inc.
program-only audio that is routed to the
right channel. Line input 1 is connected to
an audio source associated with a sports-
event “spotter” position. This source is
routed to the headphone output’s right
channel. The input trim pot associated
with line input 1 can now serve a critical
role—adjusting the relative level of the
“spotter” audio as compared to the level
of IFB channel 2. The trim pot allows the
desired “mix” to be created, providing the
user with an effective cue signal.
Talkback-to-Intercom
Sidetone Adjustment
Associated with the talkback-to-intercom
functions are sidetone trim potentiometers
that are used to adjust the talkback levels
that are being returned to the intercom
line receive audio sources. These two trim
pots are part of the analog hybrid circuit
that separates (“nulls”) talkback audio
from receive (“listen”) audio. If audio from
either or both of the intercom channels is
to be used as a headphone source, and
talkback to these intercom channels is
also desired, the sidetone trim pots may
need to be adjusted.
One trim pot is associated with the side-
tone level for each channel of the inter-
com interface. Both are accessible on
the bottom of the Model 230’s enclosure,
adjacent to the trim pots associated with
the line-level inputs. Adjusting them is very
simple, requiring only a pair of ears and
a screwdriver.
With the Model 230 configured as previ-
ously described, activate one of the talk-
back-to-intercom functions. Audio from
the connected microphone should be
heard in the configured headphone output
channel(s). Adjust the trim pot associated
with the active intercom channel so that
the desired sidetone level, relative to the
intercom receive level, is achieved. The
adjustment range is approximately 18 dB,
with the sidetone level increasing as the
trim pot is rotated in its clockwise direc-
tion. Now change to the other intercom
channel and adjust its sidetone trim pot
as desired.
Using the Model 230’s sidetone function,
talkback audio will be routed to the head-
phone outputs by means of dedicated cir-
cuitry. If this is enabled be certain to place
the two intercom sidetone trim pots to
their fully counterclockwise positions. This
will minimize the increase in sidetone level
that will occur when both the sidetone and
talkback-to-intercom functions are active.
Additional details are provided later in this
user guide.
Technical Notes
Grounding and Shielding
As previously discussed in this user guide,
the pin 1 connections on the main and
line-level talkback outputs’ 3-pin male XLR
connectors are “floating,” i.e., not con-
nected to anything within the Model 230’s
enclosure. Some audio experts might
take offense to this, complaining that
this should have been left to the user or
installer to be connected or disconnect as
desired. However, repeated field testing
found that floating pin 1 on these outputs
was the key to maintaining quiet audio.
From Fenway Park in Boston, to the
Orange Bowl in Florida, and then north-
west to Husker Stadium in Nebraska,
lifting pin 1 did the trick.
A simple solution is available if an
application does require that a ground
be available on the main and line-level