Lexicon 480L | PDF - Freeverb3

Lexicon 480L Owner's Manual
Page One
CH1
Left Channel In
CH2
Right Channel In
EFF
Effect
ANG
Speaker Angle
LFB
L-R Boost
MIX
Dry Input
The Panorama (Binauaral) Program
Panorama is a crosstalk elimination program. It increases
the apparent width of stereo sounds by eliminating
the crosstalk around the ears of the listener. One
of the major uses of this program in the 480L is to
spread the sound of a reverb or effect outside the
bounds of the loudspeakers. This is easily done with a
mixing board by putting the 480L in cascade mode with
Ambience or a reverb program in machine A, and
Panorama in machine B. The mix control in machine A
should be ALL EFFECTS. In machine B the Effect
control and the Low frequency width are used to
increase the width of the reverb, and the Dry Input Mix
control or an external mixer can be used to add the
unexpanded original sound back into the expanded
reverb.
In making expanded recordings the listener is assumed
to be exactly between the two loudspeakers,
and the speakers should be at the angle set in the
program. For this reason, this expansion is best done
at the time of playback, using a home processor.
However, there may be good reasons for doing some
expansion in a recording. Low frequencies are spread
by the program through the whole listening room —
they do not require precise adjustment. Even under
non-ideal playback conditions, some improvement
may be noted. Recordings made with ORTF, or closely
spaced omni microphone techniques, will probably
greatly benefit from some LF L-R boost, which can be
adjusted independently from the crosstalk cancellation
controlled by the EFFECT control.
This program may also be of use to professionals using
Binaural recordings to study acoustic or noise environments.
Binaural recordings played with Panorama
through a carefully set up loudspeaker system give
nearly ideal reproduction of the original recorded
sound field, at least in the front hemisphere.
Setting up the program for this application is best done
with a noise source at the input. Use CH1 to turn off the
left input level, and move your head to find a position
which gives a sharp null in the left ear. Now raise CH1
and lower CH2. The null should now be in the right ear.
If it is not, adjust ANG and the listening position until a
sharp null occurs for each ear.
About the parameters
CH1, CH2 (Left In, Right In)
These controls are simple linear attenuators on the left
and right inputs. They can be used to set up the
program, or they can be used as input balance controls.
They can also be used to trim the balance into the
L-R boost control.
EFF (Effect)
EFF sets the amount of crosstalk cancellation in the
mid frequencies, and acts as a width control. If EFF is
set to 0, and L-R boost is also set to 0, the program has
no effect on the sound.
ANG (Speaker Angle)
ANG sets the speaker angle expected in the listening
environment. This is the total angle between the speakers.
Lower settings of the speaker angle control (40° or
so) are more effective when the actual speaker positions
to be used by the listener are unknown. This is
because most listeners tend to use smaller speaker
angles, and because the effective listening area is
greater when ANG is low.
LFB (LF-LR BOOST)
LFB is a L-R bass boost with a maximum boost of 20dB.
It is similar to the Spatial Eq control in Stereo Adjust, but
works differently. It is a pure boost in the difference
channel only. It does not affect the mono channel. If
Panorama is being used to process a binaural recording
for loudspeaker reproduction, LFB should be at
least half-way up. This control is independent of EFF,
so the low frequency width can be increased without
changing the mid-frequency width.
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