Studio Technologies 55 2005 - Manual (Page 26)

Issue 5, August 2005 Model 55/56 User Guide
Page 26 Studio Technologies, Inc.
and right signals, drop the level, and send
the result out the left and right outputs.
In our application we drop the level by
6 dB. This is what many recording con-
soles implement, and is what the Studio-
Comm does too!
Talent Amplifi er Mono Function
The Model 35 Talent Amplifi ers contains
a monaural switch. The mono function
sums the left and right input signals, drops
the level of the sum by 6 dB, and sends
the sum to both the left and right outputs.
Input Level and the Talent Amplifi ers
Optimal performance of the Model 35
Talent Amplifi er depends on the head-
phone source signal levels being at
approximately the nominal input level,
either –10 dBV or +4 dBu, depending on
the confi guration. The headphone volume
is adjusted only by the level controls on
the talent amplifi ers. If the selected head-
phone source signal level is signifi cantly
less than nominal, the talent amplifi er will
simply not be able to create the maximum
volume in the headphones. While there is
some gain in the talent amplifi ers, optimal
performance still requires an input close
to nominal.
Communication Switch Noise
During fi eld trials of the StudioComm com-
ponents one item came up for discussion
concerning “thumps” in the communica-
tions functions. A brief discussion may be
useful. Electrically the Model 55 and Model
56 electronics that support the communi-
cations functions are quite quiet, not add-
ing appreciable “clicks, pops, or thumps.”
Software time delays are even added to
minimize noise when a button is pressed.
Mechanical noise being picked up by the
Model 56’s microphone can be an issue.
If the talk to phones or slate buttons are
pushed using a relatively light touch no
objectionable noise will be generated;
pressing the switches with “gusto” will
cause mechanical noise to be transferred
into the microphone. While the Model
56’s microphone is of good quality, shock
mounting it was not possible using
a cost-effective method. The fact that
the Model 56 is physically small and the
buttons must be relatively close to the
microphone adds to the diffi culty. (Note
that most all recording consoles, both
small and large, share this condition.) So
in conclusion, use a light touch on the but-
tons and everyone should stay reasonably
happy!
Power Amplifi er Input Sensitivity
Optimum StudioComm performance is
obtained when the input sensitivity of the
control room power amplifi er is adjusted
to match the Model 55’s output level.
With normal, but loud, listening levels
you should fi nd the level potentiometer
on the Model 56 to be set to about 11 or
12 o’clock. If you fi nd that you don’t have
to turn up the Model 56’s control that high,
reduce the input sensitivity of the power
amplifi er. Most power amplifi ers have con-
trols on their inputs to allow easy adjust-
ment of the input sensitivity.
Control Room Output Transient
Protection
Unique to the Model 55 Central Controller
is a power up/power down transient pro-
tection feature. It limits the chance of
damage to the control room loudspeakers
during the time when AC mains voltage is
connected, disconnected, or has signifi -
cantly changed from nominal. A combina-
tion of hardware and software is used to
monitor one of the power supply “rails.”