Studio Technologies 78 2004 - Manual (Page 28)

Issue 5, January 2004 Model 78/79 User Guide
Page 28 Studio Technologies, Inc.
for Surround
LED lights when a downmix mode is en-
abled. Normal surround operation takes
place whenever none of the four downmix
LED indicators are lit.
Monitor Output General
Functions
Four buttons and one rotary control are
associated with the monitor output func-
tions. The buttons control operation of LFE
Low-Pass Filter, reference level, mute all,
and dim. The rotary level control is used to
manually set the monitor output level.
LFE Low-Pass Filter
The LFE input low-pass filter function is
provided to emulate the processing done
by some formats to the LFE channel. Un-
like the main channels, an LFE channel is
often bandwidth restricted to save digital
“bits.” It’s important that an audio “mix”
maintain its integrity when such LFE band-
width restrictions are in place. Technically,
when enabled the LFE signal is routed
through a series of analog filters which
provide a 48 dB/octave slope with a –6 dB
frequency of 120 Hz.
To enable the LFE low-pass filter function
simply press the LFE Low-Pass button.
The associated LED indicator will light
when the filter is active in the LFE audio
path.
Philosophy dictates how the filter function
should be used. The function can be used
as a final “double check” to ensure that
material will maintain overall integrity when
digitally processed. Enabling the filter dur-
ing a final listening session should find the
spectral content remaining constant. If the
mix is impacted, content has been incor-
rectly routed to the LFE channel!
It’s also acceptable to leave the filter en-
abled at all times. This will ensure that an
audio mix will “hold up” when processed.
However, this may mask content remain-
ing in the LFE channel which, although it
won’t be present after processing, may be
confusing to mastering engineers or other
personnel who monitor the original source
material.
Reference Level
The reference level button, labeled REF,
sets the monitor output level to a preset
value. A technician, using a sound-pres-
sure-level (SPL) meter, at the time of
system installation normally sets this level.
The LED associated with the reference
level function lights whenever the function
is active. Whenever the reference level
mode is active the rotary level control is
disabled. The 4-digit display will indicate
the reference output level.
The reference LED also serves as a cali-
bration aid. If the reference level mode is
not active, and the rotary level control is
set at precisely the same level as that
stored for the reference value, the refer-
ence LED will flash. Due to the method
that the software reads the position of the
rotary level control, it’s possible that the
control can’t always be set to match the
exact reference value.
Mute All
The mute all function is highly complicated
to operate—not! Pressing the mute all but-
ton causes all eight monitor output chan-
nels to mute. The 4-digit display will always
indicate a mute condition by showing four
horizontal dashes. The mute all button is
always set to “latch” the function on and
off. The LED associated with mute all will
light whenever mute all is active. Note that