Studio Technologies 76B 2008 - Manual (Page 36)

Issue 1, July 2008 Model 76B/77B User Guide
Page 36 Studio Technologies, Inc.
for Surround
Display and Display Mode
The Model 77B’s 4-digit LED display can
be selected to show either the level of the
surround monitor output or the dialnorm
level. The display mode button is used to
select the desired mode. Two LEDs are
associated with this button, indicating
which mode is active.
Both modes will indicate level in dB. What
the digits actually represent will depend
on how the Model 77B has been confi g-
ured. When selected for the output level
display mode, the surround monitor output
level will be shown as either the amount
of attenuation or the sound pressure level
(SPL). If confi gured for the attenuation
mode the display will show the output
level as an attenuation value in reference
to the maximum output. This is in the form
of 0.5-dB steps less than the maximum
of 0.0 dB. So a display of –40.5 would
indicate that the surround monitor output
is set to be 40.5 dB below the maximum
level. As the rotary level control is moved
counterclockwise the output level will go
down and the indicated value will get more
negative.
If the Model 77B is confi gured to display
the output level in SPL, the 4-digit display
will always show the output level in positive
numbers. These numbers are intended to
represent the sound pressure level in dB
SPL, a fi gure that should directly relate to
the actual sound pressure level that the
loudspeaker system is presenting to users.
(Typically, the level value would actually
be in dBC, the C-weighted sound pressure
level.) When the reference level button is
enabled, or the rotary level control is set so
that the reference level has been reached,
the display will typically show something
in the range of 82 to 87 dB. Assuming that
the monitoring environment has been
correctly calibrated, this would indicate
that an average listening level of 85 dB,
for example, had been achieved.
When the 4-digit display is set for the dial-
norm display mode a much different piece
of information will be shown to the user. It
will show the somewhat obscure but impor-
tant dialnorm level parameter that’s associ-
ated with a surround input source. As has
been covered in other parts of this guide,
dialnorm is intended to provide a numeric
value that represents the average dialog
level associated with an audio-for-picture
element. Technically, dialnorm values can
range from –31 to –1 dB but during actual
operation they will typically be in the range
of –30 to –20 dB. The value may change
relatively frequently in conjunction with
changes to the actual audio signal. This
would be the case, for example, with a
television program that consists of alternat-
ing program and advertising segments. In
other situations the dialnorm level will only
change when an “on-air” source is switched
from typical station-originated segments to
an extended-duration broadcast program,
such as a live concert event. And on the
extreme end, in some facilities the dialnorm
level is fi xed and won’t ever change. That’s
not really in the spirit of what dialnorm is
supposed to accomplish, but c’est la vie.
Whatever the dialnorm level—the Model
77B will display it!
In both display modes a special feature is
provided to assist users in knowing if the
current dialnorm level matches a facility’s
“house” reference. This reference level,
typically in the range of –24 to –27 dB, is
entered as part of the Model 77B’s confi gu-
ration process. The “dot” in the lower-right
corner of the 4-digit display will light when-
ever the current dialnorm level matches the