JVC XP-A1000BK - Page 18

XP-A1000BK
Description
of
New
Technology
Patterns of Sound
The
acoustic
patterns
in
the
live
performance
space
can
be
classified
into
three
types:
direct
sound,
early
reflec-
tions,
and
reverberations.
Early
reflections
are
created
when
the
sound
is
reflected
off
walls
a
few
times
before
Fig.1
THE
PATTERNS
OF
EARLY
Fig.
2
REFLECTIONS
reaching
the
listener.
Each
early
reflection
has
its
own
direction
and
sound
intensity
and
is
the
most
important
factor
in
determining
the
acoustic
characteristics
of
the
performance
space.
(See
Fig.
1
&
Fig.
2)
PATTERNS OF SOUND
ear aaa etic naie CRE
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Early reflections reach the listener from
various directions
Acoustic
Characteristics
of
a
Concert
Hall
The
reflected
sound
heard
in
a
concert
hall
varies
in
character
depending
on
direction
and
intensity.
Their
dis-
tribution
can
be
plotted
as
shown
in
the
Distribution
Pat-
tern
for
Virtual
Image
Source
Locations
(Figs.
2a
through
2e.).
The
centre
of
the
many
circles
represents
the
virtual
image
source
locations;
the
size
of
the
circle
indicates
DISTRIBUTION
PATTERN
OF
VIRTUAL
IMAGE
SOURCE
LOCATIONS
Left
e
Rear o
°
°
Right
Fig.
2a
Location
of
Sound
Source:
Centre
on
the
Stage
Location of Measurement: Centre-Front
1-18
(No.
20062)
Pulsive Sound t=O
DS
G
|
Typical Patterns of Sound
ER: Early Reflections
DS: Direct Sound
REV: Reverberations
- ER
ER1
ER2
—
REV
50 to
150mS
Time —
sound
intensity.
These
figures
show
that
the
distribution
changes
as
the
measuring
position
(represented
by
the
cross
section
of
the
horizontal
and
vertical
lines)
changes.
(Figs.
2a
and
b.)
The
same
is
true
when
the
position
of
the
sound
source
is
moved
across
the
stage
of
the
hall.
(See
Figs.
2c,
2d
and
2e.)
Front
<™| Q
° Right © 0. (~O
Fig.
2b
Location
of
Sound
Source:
Centre
on
the
Stage
Location
of
Measurement:
Centre-Rear