Studio Technologies 216 - Manual (Page 14)

Issue 1, July 2014 Model 216 User Guide
Page 14 Studio Technologies, Inc.
observe that the 2-digit display is not light-
ing. For example, a Model 216 has been
operating normally but the security panel
has just been removed. To cause the
2-digit display to again light just requires
pressing either of the bottom pushbut-
ton switches. This “wakes up” the display
and resets the timer. The initial press of
either pushbutton will not cause the gain
to change or impact the phantom power
on/off status. Only when the 2-digit display
is active will the pushbuttons impact the
settings.
Microphone Preamplifier Gain
The two pushbutton switches are used
to select the gain of the microphone
preamplifier. The range is 19 to 64 dB in
3 dB steps. There’s no problem changing
the gain setting while the unit is operating.
Small audio clicks or pops might occur
during gain transitions, but this shouldn’t
be a major issue as long as associated
monitor loudspeakers are temporarily
attenuated or muted. As expected, the
2-digit LED display will directly indicate,
in dB, the selected amount of gain.
Selecting the correct amount of gain for an
application might take a little experimenta-
tion. The goal is to bring the mic’s signal
up to the Dante reference level which is
typically considered to be –20 dBFS. (This
is 20 dB below digital maximum.) Operat-
ing at this signal level will help ensure the
delivery of “clean” audio to the destination
device or devices.
There’s no “perfect” gain setting that this
guide can recommend. The two issues
that impact the setting are output sensi-
tivity of the connected microphone and
the acoustical output level of the micro-
phone’s user. With some headset micro-
phones, such as the Sennheiser HMD26,
selecting an initial setting of 43 or 46 dB
would be appropriate. Users who speak
loudly might need to have the gain reduced
to 40 or even 37 dB. Quiet users might
need 49 or 52 dB of gain.
Using the device that’s digitally connected
(via Dante) to the Model 216’s main output
channel is typically the best way to check
the signal level and the setting of the mic
preamplifier. Most devices have some
method of providing an indication of the
digital level, either in the form of a numeri-
cal value, virtual meter, or LED-based meter
display. The Studio Technologies’ Model
5202 Dante to Phones and Line Output
Interface would also be an excellent means
of monitoring the Model 216’s output level.
The Model 5202 provides a 2-channel LED
level that is calibrated in dBFS.
A dual-color LED, located on the back
panel directly below the microphone in-
put connector, is provided as an aid when
using the Model 216. It can also be useful
when setting the gain of the Model 216’s
microphone preamplifier. It provides a
3-step indication of the output level of
the microphone preamplifier. It will light
green when the signal level is –40 dBFS or
greater, a mix of green and red when the
signal level is –14 dBFS or greater, and red
only when the signal level is –4 dBFS or
greater. When the gain of the microphone
preamplifier is set optimally a normal signal
applied to the microphone input will cause
the LED to light green with an occasional
“peak” signal causing the LED to light both
green and red at the same time. A more
conservative gain setting would find that
the LED would only light green. A gain
setting that results in the LED ever lighting
only red is incorrect. The gain must be re-
duced or the audio quality will be severely
compromised.