QUAD 33 - Loudspeaker Phasing

duction that voice will
take up
a
position
at the
centre
of, and in
the
plane
of the loudspeakers.
For
natural
sound, therefore,
the loudspeakers
should
radiate
similar
power
to
that of the
original voice. If
on the
other
hand
the voice is
picked
up
some way from
the microphone
in
a more live
studio, then the voice
on
reproduction
will
take
up a
position
some distance
behind the loud-
speakers
and
it is
clear that
the
power
required
for
natural
sound is now very much
less. The
position
or
perspective
of the reproduced
sound
is fixed
at the
studio
end
and
there is little
that can be
done at the
listening
end to alter it. It follows
that the volume
setting for natural
sound is to a large
extent fixed at
the
studio end.
Filters
(See
page
16).
The
filters
affect the extreme harmonic range
only and
do
not interfere
with musical
brilliance.
Their
purpose
is
to enable the maximum
content
of the
programme
to be reproduced with
the minimum
distortion.
With
most types
of
recording
the
distortion
rises
Pape
Fourteen
rapidly
at high
frequencies
and
the wider
the loud-
speaker range
the more
audible
this will
be. It may
be
removed
or
mitigated
by rotating
the filter
slope
control
anti-clockwise
from
the
level position.
As the control
is
rotated,
the
quality
and
"
cleanness
"
of the reproduc-
tion
will
improve.
There will,
however,
be a
point
beyond which
further rotation
degrades
the
sound due
to loss
of the useful harmonic
range.
The
pushbuttons
marked
5K,
7K and l0K,
determine
the frequency
at which filtering
commences
and
that
marked
7K is
the most
useful for modern
recordings.
Pressing
the 5K
pushbutton
transposes
the filter
opera-
tion to a lower frequency
for
use with
older recordings
and
pressing
the lOK
pushbutton
transposes
it
to a
higher
frequency where it
is
useful with very
good
records
or
high
quality
radio
transmissions.
The Cancel
button bypasses
the
bass,
treble
and filter
controls to
give
a level response.
This
position
is a
reference
by
which
the effects
of the settings
of the
other
controls may be
judged
without
upsetting the
position
of these controls.