Harman Infinity PRIMUS 1270 - Subwoofer Enclosure Types; Sealed Enclosures; Vented Enclosures; Mounting and Technical Data

~ lnfiniW PRIMUS 1210
- HARMAN
THANK YOU for choosing a Infinity
SEALED ENCLOSURES
Primus subwoofer. These subwoofers
The air trapped Inside a sealed enclosure
are designed to suit a broad range of car
Is compressed when the subwoofer moves
audio applications and can be used In a
rearward and Is rarefied when the
wide variety of enclosure types to produce
subwoofer moves f1rward. In both cases,
extended, powerful bass In a llmlted
the air inside and outside the box will
amount of vehicle space. To get the most
seek equilibrium by pushing and pulling on
performance from your new subwoofer, It
the subwoofer cone. The result Is a
Is strongly recommended that you have a
stiffer suspension when compared to the
qualified professional Install your
subwoofer operating In free air. This
subwoofer. Although this manual does
means that the subwoofer's cone will be
provide general Instructions about
harder to move at low frequencies, a
Installing these Primus subwHfers, It does
condition which pr11tects the subwoofer
not include enclosure construction details
from physical overexcurslon, but
or exact Installation methods for any
requires more power than other designs
particular vehicle. If yeu do nit feel that
t, achieve a given acoustic output.
you have the necessary experience, do not
attempt the Installation yourself, but
SEALED-ENCLOSURE PERFORMANCE
Instead ask your authorized Infinity dealer
ADVANTAGES
about professional installation options.
• The in-vehicle performance will have
Remember to keep your sales receipt In a
the flattest overall frequency response.
safe place, along with this manual, so
• The In-vehicle response will have the
that both are available for future
widest bandwidth. (Usable l1w-frequency
reference,
response Inside the vehicle will be
below 20Hz.)
WARNING
• An optimum sealed enclosure will always
Playing loud music in a vehicle can hinder
be smaller than an optimum enclosure of
your ablllty to hear traffic and
another type.
permanently damage your hearing. The
maximum volume levels achievable by Infinity
SEALED-ENCLOSURE PERFORMANCE
speakers when combined with high-power
TRADE-OFFS
amplification may exceed safe levels for
• An optimum sealed enclosure will have
extended listening. Using low volume
lower overall efficiency than an
levels Is recommended when driving. Infinity,
optimum enclosure of another type,
Inc. accepts no liability for hearing loss,
• A subwoofer In an
bodily In Jury, or property damage as a
optimum sealed enclosure will require
result of use or misuse of this product.
more amplifier power to achieve a given
REPRODUCING
acoustic output than In an optimum
BASS IN VEHICLES
enclosure of another type.
Depending on the size of your vehicle's
SEALED-ENCLOSURE CONSTRUCTION
interior listening space, reproduced bass
Sealed-enclosure construction is straight-
frequencies below 80Hz will be boosted
forward and forgiving of errors In volume
by nearly 12dB per octave as frequency
calculation, but air leaks should be
decreases. This phenomenon, known as
avoided. Use medium-density fiberboard
the vehicle's transfer function (Dr cabin
(MDF), glue and screws to construct the
gain), plays an Important role In shaping
enclosure, and seal all joints with silicone
the subwoofer's frequency response In
caulk.
your vehicle.
SUBWOOFER
RECOMMENDATION
ENCLOSURE TYPES
Subwoofers In sealed enclosures are
The subwoofers are designed to perform
recommended fer enthusiasts who prefer
best In moderately sized sealed
accurate music reproductlen and flat
enclosures, vented enclosures and
frequency response, for those who have a
prefabricated band-pass enclosures.
smaller space to devote to a subwoofer
Infinite-baffle mounting Is possible, but
enclosure, and for those who have plenty
the subwoofer's mechanical power
of amplifier power devoted to driving the
handling will be reduced because there
subwoofer. The sealed-enclosure design
will be no volume of air to stiffen the
indicated In this manual represents the
subwoofer's suspension and prevent
best compromise between low-frequency
overexcurslon. If you choose lnfinlte-baf-
extension and flat response.
fie mounting, consider the RMS and peak
VENTED ENCLOSURES
power-handling ratings to be half of what
Is listed In the specifications In this
A vented enclosure acts like a sealed
manual.
enclosure at frequencies above Its tuned
You should choose an enclosure type
(resonance) frequency, At resonance
(which Is defined by the vent), the vent
based on the amount of cargo space you
produces the majority of sound - the
can devote to the enclosure, the amount
subwoofer cone is nearly stationary while
of power you will use to drive your
the air inside the vent vibrates. This
subwoofer(s), and your llstenlna habits.
provides greater mechanical power
handling at and above resonance, but
reduced mechanical power handling below
resonance. Since the subwoofer cone and
voice coll don't move much at resonance,
airflow across the voice coll Is minimized
and thermal power handling Is reduced
slightly at resonance.
Vented enclosures provide better
efficiency In the 40Hz - 60Hz range, at
the expense of sound output In the lowest
octave (below 40Hz). The use of an
Infrasonic filter Is recommended with
vented enclosures. An 1ptlmum vented
enclosure for a Primus subwoofer Is larger
than an optimum sealed enclosure.
VENTED-ENCLOSURE PERFORMANCE
ADVANTAGES
• An optimum vented enclosure has
greater efficiency and higher 1utput in
the 40Hz- 60Hz range than an optimum
sealed enclosure.
• An optimum vented enclosure provides a
greater sensation of bass than an
optimum sealed enclosure.
• A subwoofer In an optimum vented
enclosure will require less amplifier
power to achieve a given acoustic
output (down t1 the enclosure's
resonance frequency) than in an
optimum sealed enclosure.
VENTED-ENCLOSURE PERFORMANCE
TRADE-OFFS
• Reduced output In the lowest octave
(below 40Hz).
• Reduced mechanical power handling
below the enclosure's resonance
frequency. The use 1f an electronic
Infrasonic filter Is strongly recommend-
ed to reduce the chance 1f overdriving
the subwoofer below the enclosure's
resonance frequency.
• An optimum vented enclosure will
always be larger than an optimum
sealed enclosure.
VENTED-ENCLOSURE CONSTRUCTION
Vented-enclosure construction Is more
difficult than the construction of a sealed
enclosure. The enclosure volume and port
dimensions have a specific relationship
with the physical and electromechanical
characteristics 1f the subwoofer,
requiring that the recommended
enclosure volume and port characterls-
tics be strictly observed. As with sealed
enclosures, use medium-density
fiberboard (MDF), glue and screws to
construct the enclosure, and seal all
Joints with silicone caulk.
RECOMMENDATION
Subwoofers In vented enclosures are
recommended for enthusiasts who prefer
accentuated bass response, for those who
have plenty of cargo space to devote to a
subwoofer enclosure and for those who
will use a less powerful amplifier to drive
their subwoofer. The volume and port
dimensions Indicated must be followed
precisely to ensure 1ptlmum
perf1nunce.
MOUNTING THE
SUB WOOFER
The subwoofers should be
mounted from the outside of the
enclosure.