to improve the structural strength
of the cabinet. Low Riders can
generate enormous forces inside
the enclosure, and panels that
aren’t tiff enough will vibrate or
if the cabinet panels are not stiff
enough add more bracing.
Vents shown in the examples
require standard Schedule 40 PVC
pipe for vent construction. The pipe
should be dadoed tightly into the
back of the baffle and glued firmly
in place with high quality epoxy or
high strength industrial grade hot
glue. Roughen up the outside of
the pipe to improve the glue bond.
Radius the insides of the vent end
to improve air flow and reduce vent
noise.
Vents for these enclosures
are much longer than typical
for a sound reinforcement sub
woofer. This reflects the special
characteristics of the Low Riders
design that make it possible to
combine a large, high excursion
woofer with an unusually small
enclosure. For best performance,
the inside ends of the vents should
be a distance of at least one vent
diameter from any interior wall of
the enclosure. The vent should
be straight, without elbow fittings
or other methods to bend it for
greater length. Vent diameter
should not be decreased, as high
air velocity will result in noise and
reduced power handling.
Be sure to allow for the
displacement of the vent, bracing
and woofer in your enclosure
design before building it. Mistakes
in net volume will mis-tune the
enclosure and can drastically
reduce performance. This requires
a considerably amount of planning
before construction, but is well
worth the extra effort.
Line the inside of the enclosure
with polyester fiber batting such
as quilt stuffing. For bandpass
loosely fill the sealed side, leave
the vented side empty, and
place the low Rider’s magnet in
the vented side for cooling. The
batting material should conform
to California bedding fire codes.
Attach the batting with spray
adhesive or staples and keep
material away from the end of the
vent tube where it can be pulled in
by air flow.
Handles, protective corners,
cabinet covering, grille materials
and crossovers are available
through Peavey Accessories. Take
particular care when positioning
handles, as sub woofers tend to be
large and heavy.
Do not use ¼” phone plugs or
jacks in the construction of your
enclosures. Power capacity of
Low Rider sub woofers is well
above safe limits for phone
plugs and jacks. Neutrik
®
Speakon
®
connector’s are highly
recommended, and internal
cabinet wiring should be at least 16
gauge stranded copper wire.
These instructions are a general
guideline for design. Proper
construction techniques, good
planning and common sense will
result in a reliable, high quality,
high performance system.
Peavey in no way accepts liability
for any damage, accidents or
injury that may result from design,
construction or operation of
enclosures using this information.
Due to Peavey’s continuing efforts
to improve products, features
and specifications are subject to
change without notice.
PARAMETERS
Thiele-Small parameters for Low
Rider subwoofers follow. This data
is for use in designing enclosures.
Numerous software packages
are available that use this data
to simulate the response of the
driver and enclosure together
for optimum performance in any
application.
PARAMETER DEFINITIONS
Znom
: The nominal impedance of
the driver in Ohms.
Revc:
DC resistance of the driver
in ohms, also known as Re.
Sd:
The functional radiating
surface area of the cone assembly
in meters 2.
BL:
Efficiency of the voice coil and
magnet system in Tesla meters.
Fo:
Free air resonance. Also
known as Fs.
Vas:
Volume of air having the
same compliance (springiness) as
the driver’s suspension.
Cms:
Restorative force of
the driver’s suspension in
micrometers/Newton.
Mms:
The total mass of the
moving parts of the loudspeaker,
including the air load, in grams.
Qms:
Resonance characteristics
of the mechanical factors of the
loudspeaker.
Qes:
Resonance characteristics
of electrical factors of the
loudspeaker.
Qts:
Resonance characteristics
of the electrical and mechanical
factors combined together.
Xmax:
Distance the cone can
move in one direction before the
coil begins to leave the magnetic
gap.
Le:
Inductance of the voice coil in
millihenries.
SPL:
Typical sound pressure level
at 1 watt, 1 meter.
no:
Electrical to acoustical
conversion efficiency in percent.
Vd:
Air displacement of the driver
from negative Xmax to positive
Xmax.
Pmax:
Maximum continuous
program power in watts.
Disp:
Volume displaced by the
driver inside the cabinet when
mounted on its rear flange.
