Wide - Bang & Olufsen BeoLab 90 Technical Sound Manual

room. This gives the same result at the
listening position as if you used
acoustically absorptive materials on
your walls, or changed the geometry of
your listening room to avoid having
first reflections in the listening position.
Figure 5.5: Conceptual drawing showing
the beam width of the Narrow Beam.
You should note, however, that there
are side-e ects to using a narrow
beam width. The most obvious may be
in the low frequency behaviour of your
BeoLab 90's. Generally, the overall
impression will be that the bass
content is "tighter" or has more
"punch" when the BeoLab 90 is in
narrow mode. However, this e ect is
also dependent on the setting of
another parameter described in
Latency Mode.
Figure 5.6: Press the sector (or "pizza
slice") on the BeoLab 90 interface to
change the Beam Width to Narrow.
A second potential side e ect is the
sensitivity of the system to an incorrect
listening position. You may notice that,
in narrow mode, it is critical that you
are seated at exactly the correct
listening position in order to achieve
both precise and accurate stereo
imaging. Small deviations in listening
position may result in noticeable
detriments in the spatial
representation of your recordings.
Beam Width: Narrow
90
64
5
125
120
250
0
500
1000
−5
2000
150
4000
−10
8000
−15
180
210
240
270
Figure 5.7: Polar plot of the directivity of
the Narrow Beam. Latency: Long
Beam Width: Narrow
150
100
50
0
−50
−100
−150
100 1000
Frequency [Hz]
Figure 5.8: Full frequency range direc-
tivity plot of the Narrow Beam. Latency:
Long. Contours in steps of 3 dB, nor-
malised to the on-axis response.

5.1.2 Wide

As mentioned above, when the BeoLab
90's are set to a narrow beam width,
they are somewhat unforgiving of a
mis-placement of the listening
position. This is particularly noticeable
when you are listening to recordings or
movies with friends and family.
Consequently, in more social or
passive listening situations, it is likely
preferable that the BeoLab 90's have a
wider beam width, more similar to
BeoLab 5 loudspeakers. Although this
will likely result in more energy in the
sidewall reflections, it also ensures that
there is a more equal distribution of
the direct sound across a wider
listening area in the room.
16
60
30
0
330
300
Figure 5.9: Conceptual drawing showing
the beam width of the Wide Beam.
0
−2
−4
−6
−8
−10
−12
10,000
Figure 5.10: Press the curved line shown
above to change the Beam Width to
Wide (Front).
64
125
250
500
1000
2000
4000
8000
180
Figure 5.11: Polar plot of the directivity
of the Wide Beam. Latency: Long
150
100
50
0
−50
−100
−150
100
Figure 5.12: Full frequency range direc-
tivity plot of the Wide Beam. Latency:
Long. Contours in steps of 3 dB, nor-
malised to the on-axis response.
Front
Left
Front
Beam Width: Wide
90
5
120 60
0
−5
150
−10
−15
210
240 300
270
Beam Width: Wide, Front
1000 10,000
Frequency [Hz]
Front
Right
30
0
330
0
−2
−4
−6
−8
−10
−12