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The correct acoustic load, normally
the type of enclosure and volume
made available to the subwoofer, is
of prime importance for maximum
performance. All pistonic acoustic
devices (in this case subwoofers)
require a defined acoustic load to
work correctly. This means the type
of charge (sealed or bass reflex)
and volume (litres / cubic ft) must
be chosen wisely, to gain maximum
performance. Never choose "any"
ready prepared subwoofer enclosure.
They may accept your subwoofer,
concerning the hole cut-out size for
chassis, but do they match the volume
or type of charge as defined in the
subwoofer parameters?
Sealed / closed box enclosure
All K2 Power subwoofers (except
the 46 KX 4) have been carefully
optimised to work in sealed or closed
box enclosures. This type of enclosure
ensures sub bass frequencies remain
full and controlled. The available
excursion of the sub is far more
stable, for controlled linearity limiting
distortion, ensuring maximum perfor-
mance is maintained. The added
benefit of a properly defined sealed
enclosure, is that it remains compa-
ratively small in size. Compared to a
defined bass reflex enclosure, which
normally has a slight increase in
the sound pressure level, K2 Power
subwoofers have improved power
handling characteristics. Therefore
this slight reduction of level can
be compensated, with increased
amplification.
Installation
The mighty 46 KX 4 subwoofer incor-
porates a unique feature, consisting
of 4 individual wound voice coils,
intertwined together on the same
vented aluminium former. Each voice
coil winding has an impedance of 1
ohm, giving greater flexibility. Note
that core section of connecting cables
and complete amplifier compatibility
must be verified before, for load
ratings from 0.25, 1 or 4ohms
(fig.
F, G, H)
.
"Bi-amping" can also be included for
the 46 KX 4. Thus load impedance’s
of 2x0.5 ohms and 2x2 ohms, can be
included for parallel or series circuits
(fig. I, J)
.
"Quad amping" can be included,
with 4x separate amplifiers, offering
identical specifications. The impedance
load will be approximately 1 ohms
(fig. K)
. Again, each amplifier power
and load rating must be compatible
for 1 ohms nominal impedance.
Cut-off frequency
Generally, it is accepted the frequency
scale is from 60 to 100Hz, depending
on many parameters (cabinet loading,
exterior load of vehicle interior etc,
etc). If in doubt, we recommend a
cut-off frequency of approximately
80Hz be selected. Too high a cut
off frequency and the "staging" will
be uneven. The bass frequencies
will become directional. Too low a
cut-off frequency and the general
performance maybe reduced.
Finally a process of "trial and error"
can be used to define this aspect,
for maximum enjoyment of your K2
Power KX series subwoofers.
The 46 KX 4 subwoofer has been
developed exclusively to work in bass
reflex enclosures. Due to the large
surface area available, with high
strength multi-ferrite motor structure,
together producing high efficiency
necessary for dynamic power SPL
installations.
Any bass reflex enclosure uses an
acoustic suspension or spring, in
the form of a port. The port whether
a tube, or slot must be correctly
calculated, concerning area and
length to the volume chosen. The
air that passes through the port is
effectively the spring and pressure
load on the subwoofer diaphragm.
To reduce air whistling, the port
should remain smooth internally, with
maximum aerodynamic characteristics
applied throughout. For a port-tube
application, it is advised to use
the maximum diameter possible
corresponding to the appropriate
length; this will further reduce wind
turbulence.
The enclosure structure should be
strong and rigid throughout, not only
due to the weight of the 46 KX 4, but
notably for the amount of air pressure
displacement produced from the
diaphragm movement.
Choosing the correct enclosure or
acoustic load (general)
Bass-reflex enclosure
Connections 46 KX 4
English
notice sub k2 power gb 5
7/01/04, 17:21:50
