Studio Technologies 76B 2012 - Manual (Page 17)

Model 76B/77B User Guide Issue 3, August 2012
Studio Technologies, Inc. Page 17
for Surround
to match the digital input source’s “0 VU” or
average point. The digital input reference
level can be selected from four choices:
–20.0, –18.0, –16.0, and –14.0 dBFS. Note
that this parameter sets, as a group, the
input reference level for all of the Model
76B’s digital input connections. The Society
of Motion Picture and Television Engineers
(SMPTE) recommends a reference level
of –20 dBFS, a value which is also exten-
sively used in professional audio applica-
tions. The recommended digital reference
level for PAL broadcast applications is –18
dBFS. The other two levels were included
because… well, we can’t remember why!
But it seemed like a good idea at the time. If
you end up using the –16.0 or –14.0 dBFS
settings please let us know why and we’ll
add that information to the next version of
this user guide!
Monitor Output Nominal Level
The nominal level of the six channels as-
sociated with the surround (5.1) output
are configured, as a group, to match the
requirements of an installation. This set-
ting defines the analog output level when
a digital input source, at its reference level,
is connected and the monitor output level
is at its maximum. The choices are 0.0 or
+4.0 dBu. Most applications will find the
+4.0 dBu setting correct as it meets the
dominant worldwide audio standards. For
broadcast applications that follow the PAL
standards the 0.0 dBu setting may be
appropriate.
A final review of the two previously selected
settings might now be in order. The most
common input and output combination will
have a digital input reference level of –20.0
dBFS and a monitor output nominal level of
+4.0 dBu. For PAL broadcast applications
a setting of –18.0 dBFS for the digital input
and 0.0 dBu for the analog outputs would
be typical.
Input Select Buttons
The three input select buttons, along with
the group select button, allow six source
configurations to be selected for monitor-
ing. The Model 76B has connections for
two surround (5.1) and three stereo
(2-channel) AES3id digital audio sources.
Any of these sources can be assigned
to any of the input select buttons. To fit
broadcast applications where it’s typical
for non-stereo pairs to share an AES3id
2-channel path, the individual left and right
audio channels of stereo inputs A and B
can be assigned to separate input select
buttons as required. These “mono” signals
will be routed to the center monitor output
channel.
Spending time reviewing the input select
button configuration function may prove
very worthwhile. It is a unique feature of
the StudioComm for Surround system
and offers a great opportunity to optimize
monitoring performance.
Reference Level
For audio-with-picture applications it’s
often beneficial for monitoring to be done
in reference to a known loudspeaker level.
This is often referred to as “mixing to 85
dB” on the monitors. The StudioComm for
Surround system allows a precise monitor
output level to be stored, and then enabled
by pressing the Model 77B button labeled
Reference Level. Setting the reference
level is very simple but care is required:
1. Set up a precision sound pressure
level (SPL) measuring device at the
desired listening location.