Filter
Top Products
Model 233 User Guide Issue 1, September 2007
Studio Technologies, Inc. Page 33
one of the talkback outputs is active. The
level control on the far right adjusts the
side-tone level. When the sidetone level
control is in its fully counterclockwise posi-
tion the sidetone signal will always be fully
muted.
Astute readers will realize that sidetone au-
dio can also be provided from the intercom
cue sources during Model 233 talkback to
intercom activity. This “passive” sidetone
is created in the intercom interface’s ana-
log talk/listen hybrid sidetone (null) circuit.
Trim pots allow the intercom sidetone level
to be adjusted over a limited range. To
get maximum performance when either or
both intercom channels are used as a cue
source one simple calibration process may
need to be performed. This involves ad-
justing the sidetone (null) trim pots to their
fully counterclockwise positions, providing
minimum sidetone level. This will reduce
the level “build up” that would occur when
both the main and the intercom sidetone
audio signals are sent to the headphone
output. The goal is for the sidetone level to
remain as constant as possible, no matter
what function—main output, talkback-to-
line-level-output, or talkback-to-intercom—
is active.
Advanced
Operation
Adjusting the Line Input
Trim Pots
As has been previously mentioned, associ-
ated with the two line inputs are trim pots
that allow the input levels to be adjusted.
The two trim pots are accessible by way of
round openings in the bottom of the Model
233’s enclosure. By adjusting these trim
pots, signals with a nominal signal level of
–12 dBV to +6 dBu can be effectively used
as cue sources. Unfortunately, there are no
definitive rules regarding how best to adjust
the trim pots, but some suggestions may
prove to be valuable. Depending on how
the line inputs are utilized, the trim pots
can be used to either adjust the absolute
level of each line input signal, or to ad-
just the relative level of the signals when
compared to other sources. The following
examples may provide some clarification.
Let’s begin with an application that has
a stereo cue source connected to the line
inputs. The cue source selection switches
are configured to create a stereo head-
phone output with line input 1 assigned
to the left channel and line input 2 assigned
to the right channel. Begin the trim pot
adjustment process by moving the user
level controls (located on the front panel)
to their detent (50% of rotation) positions.
Then, with the stereo cue source provid-
ing signal at its normal level, adjust the
trim pots to provide a comfortable level
Figure 23. Bottom view showing line input and
talkback-to-intercom sidetone trim pots