Studio Technologies 76B 2008 - Manual (Page 32)

Issue 1, July 2008 Model 76B/77B User Guide
Page 32 Studio Technologies, Inc.
for Surround
surround (5.1) signal to be “folded down”
(mixed) to stereo (2-channel). The other
allows a stereo signal to be converted to
mono. Using the downmix functions simply
requires pressing the desired button. The
buttons are set to always “latch” the func-
tions on and off. An LED is located adja-
cent to each button and lights whenever its
respective function is active. Please refer
to the Technical Notes section of this guide
for a detailed description on how the down-
mix functions perform their tasks.
5.1 to S
tereo
When the 5.1 to stereo downmix function
is enabled the LS, RS, and C channels
associated with a surround signal are
combined (“folded down”) with the L and
R signals to create a 2-channel stereo (left
and right) signal. The resulting stereo sig-
nal, sometimes known as LoRo, is routed
to the L and R surround monitor output
channel. The C, LFE, LS, and RS monitor
output channels are muted. By utilizing this
downmix function phase relationships and
inter-channel level issues can be quickly
observed.
Stereo to Mono
The stereo to monaural downmix function
combines the left and right audio channels
to create a single-channel monaural signal.
This signal is sent out the C (center) moni-
tor output channel while the L, R, LS, RS,
and LFE channel monitor output channels
are muted.
Note that when a surround source is
selected for monitoring, the 5.1 to stereo
downmix function will automatically enable
whenever the stereo to mono downmix
function is enabled. This ensures that an
operator will hear a mono signal created
by folding down all channels associated
with the selected surround input. The Mod-
el 77B associates the state of the downmix
functions with the currently selected input.
For example, if input 4 is the selected input
source and the 5.1 to stereo downmix
function is enabled, this condition will be
“remembered” when switching to a stereo
or monaural input source. Upon returning
to input 4, the 5.1 to stereo downmix func-
tion will again become active.
Note that a specifi c downmix function
can only be enabled when it is applicable
for the currently selected input source.
This means that the 5.1 to stereo down-
mix function can only be enabled when a
surround (5.1) input source is selected.
Neither of the downmix functions can be
enabled when an input source confi gured
for monaural is selected. This is because
an input of this type is already monaural
(one channel) and wouldn’t be impacted
by any additional fold down.
Monitor Output General
Functions
Four buttons and one rotary control are as-
sociated with the surround monitor output
functions. The buttons control operation
of the reference level, mute all, dim, and
dialnorm enable functions. The rotary level
control is used to manually set the monitor
output level. These buttons and the control
do not impact the auxiliary monitor output.
Reference Level
The reference level button sets the
surround monitor output level to a preset
value. Technical personnel, using a sound-
pressure-level (SPL) meter and precision
signal source, should have set this level
to meet the requirements of the specifi c