Studio Technologies 68A 2001 - Manual (Page 31)

Model 68A/69A User Guide Issue 1, March 2001
Studio Technologies, Inc. Page 31
for Surround
e.g., surround signals converted to stereo;
stereo signals converted to mono. How
these functions affect the audio signals
will greatly depend on how the Model 69A
is configured. Being aware of the selected
configuration will allow the functions to
serve a more useful role.
Downmix
The downmix function allows surround
signals to be mixed or “folded down” into
a stereo (left and right) signal. Phase
relationships and inter-channel level is-
sues can be quickly observed. Please
refer to the Technical Notes section of
this guide for a detailed description of
how the downmix function mixes surround
to stereo.
Using the downmix function simply re-
quires the downmix button to be pressed.
The downmix button is always set to
“latch” the function on and off. The associ-
ated LED lights when downmix is enabled.
The stereo signal created by the downmix
function is routed to the left and right
channels of the surround or the stereo
output, depending on which is active.
Depending on how the Model 69A Control
Console is configured, the downmix func-
tion may automatically enable whenever
the mono function is enabled. This is
provided to ensure an operator hears a
valid mono signal when a surround source
is selected as an input.
Mono
The operating characteristics of the mono
function depend on the Model 69A Control
Console’s configuration. Two mono modes
are available, as are four attenuation
levels. In the mono-to-left-and-right mode
the function combines (sums) the signals
on the left and right channels and routes
the result to both the left and right monitor
output channels. This method is the same
as found on many stereo-oriented audio
consoles. Useful for music mixing, it’s
not true monaural but rather binaural. As
expected, the mono signal will be routed
to the left and right channels of either the
surround or the stereo monitor output,
depending on which output is selected
by way of the surround/stereo button.
In the mono-to-center mode the mono
function combines (sums) the left and
right channels and routes the result to
the center channel of the surround output.
This function allows a more accurate
reproduction of a mono signal, but may not
be suitable for all operators. As expected,
in the mono-to-center mode the mono
signal will always be routed to the sur-
round center channel, no matter whether
the surround or the stereo output is se-
lected by way of the surround/stereo
select button.
To enable the mono function simply re-
quires the mono button to be pressed. The
mono function is always set to “latch” the
function on and off. The associated LED
will light whenever mono is enabled.
Bandpass Filter for Mono-to-Center
Mode
A special feature has been included to
assist an operator in determining compat-
ibility with “real world” playback environ-
ments. A bandpass filter can be inserted
into the path of the mono signal when it is
being routed to the center channel. This
allows the simulation of the response of
a loudspeaker associated with an inexpen-
sive monaural television or portable radio.
The filter passes signals in the range of
100Hz to 5kHz, while rejecting those
above and below.