Studio Technologies 761 - Manual (Page 33)

Model 761/771 User Guide Issue 1, March 2008
Studio Technologies, Inc. Page 33
for Surround
alternate action manner to change the
current state of the output. An associ-
ated LED lights whenever the director cue
output is active. The director cue output is
not impacted, nor does it impact any of the
other Model 771 functions.
Display and Display Mode
The 4-digit LED display can be selected
to show either the output level or the
dialnorm level. The display mode button
is used to select the desired mode. Two
LEDs are associated with the button, indi-
cating which mode is active. When select-
ed for the output level display mode, what
the digits actually show will depend on how
the Model 771 is confi gured. If confi gured
for the attenuation mode the display will
show the output level as an attenuation
value in reference to the maximum output.
For example, when the rotary level control
is set to its fully clockwise position the dis-
plays will typically show 0.0. This indicates
that no attenuation is taking place in the
signal path. (The signal path starts with the
selected input source and ends with the
monitor outputs.) As the rotary level control
is moved counterclockwise readings such
as –20.0 or –35.0 would be typical.
If the Model 771 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. Assuming that
the monitoring environment has been
correctly calibrated, this would indicate
that an average listening level of 85 dB
SPL, 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 im-
portant dialnorm level parameter that’s as-
sociated with the HD primary input source.
As has been covered in other parts of this
guide, dialnorm is intended to provide a
numeric value that represents the aver-
age 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 frequently in conjunction
with changes to the actual audio signal. In
other situations the dialnorm level will only
change when certain sources, such as a
live 5.1 surround event, are being “aired.”
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 771 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 771’s
confi guration process. The “dot” in the
lower-right corner of the 4-digit display will
light whenever the incoming dialnorm level
matches the stored reference level. Refer
to Figure 8. This feature can be useful in
broadcast transmission and distribution
applications. In theory, any time the