Control Parameters
5.1
Beam Width Control
The beam of sound that is radiated
from the BeoLab 90 can be adjusted by
selecting from three options:
•
•
•
Beam Control
Master
Distance
Level
Left
3.5 m
5.0 dB
Distance
Level
3.5 m
5.0 dB
Master
Left
3.5 m
5.0 dB
Wide sound
...
Beam Control
Wide sound
...
Beam Control
Level
Wide sound
Figure 5.1: The Beam Control menu for
the Master loudspeaker. To switch be-
tween the Master and the Slave loud-
speaker, swipe the upper area of the
screen left and right.
Note that, if an Active Room
Compensation zone has been created,
and is applied to the preset you are
currently editing, then an appropriate
filter setting will be calculated each
time you change Beam Width. This
calculation takes approximately 20
seconds to perform, and is indicated by
a progress wheel. If you wish to
audition differences in Beam Width
more quickly, this can be done by
disabling the ARC filter for the preset in
the Room Compensation menu.
5.1.1
Narrow
Sit in the “sweet spot” – a location in
your listening room that is exactly the
same distance from each of your
BeoLab 90’s, and where the two
loudspeakers are facing (shown in
Figure
). Using your BeoLab 90
interface, set the Beam Width Control
to “Narrow”.
"Reflection-free Zone"
Figure 5.2: A “perfect” loudspeaker con-
figuration with BeoLab 90’s. Both loud-
speakers are aimed at the listening po-
sition.
The distance from the listen-
ing position to each loudspeaker is the
same as the distance between the two
loudspeakers. For more detailed infor-
mation on loudspeaker configuration,
see
Appendix 1: Recommendations for
While facing a point located at the
centre between the two loudspeakers,
play “Tom’s Diner” (recorded by
Suzanne Vega in 1987 for her album
“Solitude Standing”). Vega’s voice
should appear to float at a position
between the two loudspeakers. If her
voice does not appear to be located
exactly mid-way between the two
loudspeakers, it is likely that you are
sitting slightly closer to one
loudspeaker than the other – in other
words, to one side of the sweet spot.
Try moving slightly side-to-side and
pay attention to the lateral movement
of Vega’s voice in space.
This ability for a pair of loudspeakers to
deliver the illusion of a sound coming
from a location in space between them
is called
phantom imaging
or
stereo
imaging
or simply
imaging
.
Now pay attention to the apparent
distance
to the voice. If the Beam
Width Control of the loudspeakers is
set to “Narrow” mode, the voice will
appear to floating roughly half-way
between you and the loudspeakers.
This is shown in Figure
tri
tri
tom
tom
tom
hh
voice
bongos
bk
bk
bass
bass
gtr
synth pad at end
sax
snare
"choir"
"choir"
cow
synth fx around 2:20
shake
tri
tri
Figure 5.3: A map of the phantom im-
age location of the voice (shown in red)
in Suzanne Vega’s recording of Tom’s
Diner. Beam Width: Narrow
Change the track to Jennifer Warnes’s
recording of “Bird on a Wire” from the
Album “Famous Blue Raincoat: The
Songs of Leonard Cohen”. In this
recording, there are many more
instruments and voices, however, it
should be very easy to locate the
position of each of those sources as
coming from somewhere between the
two loudspeakers. A partial map of
these locations is shown in Figure
tri
tri
tom
tom
tom
hh
voice
bongos
bk
bk
bass
bass
gtr
synth pad at end
sax
snare
"choir"
"choir"
cow
synth fx around 2:20
shake
tri
tri
Figure 5.4: A map of the phantom im-
age locations of instruments and voices
in Jennifer Warnes’s recording of Bird on
a Wire. Beam Width: Narrow.
BeoLab 90 is able to deliver such a
precise stereo imaging for active
listening because it is able to reduce
the amount of energy in the reflections
off the side walls of your listening
15