Infinity 1042w, 840w, 1242w, 1040w, 1240w User Manual

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840w,1040w,1042w,

1240w,1242w

reference series

YOUR CAR AND BASS REPRODUCTION

CHOOSING AN ENCLOSURE

THANK YOU for choosing an Infinity Reference
Series subwoofer. Reference Series subwoofers
are designed to suit a broad range of mobile­audio applications and can be used in a wide
variety of enclosure types to produce extended,
powerful bass in a limited amount of vehicle
space. To ensure maximum subwoofer perfor­mance, we strongly recommend that installation
be left to a qualified professional. Although these
instructions explain how to install a Reference
Series subwoofer in a general sense, they do not
show box-construction details or exact installation
methods for your particular vehicle. If you do not
feel you have the necessary experience, do not
attempt the installation yourself, but instead ask
your authorized Infinity dealer about professional
installation options.

Remember to keep your sales receipt with this
manual in a safe place so both are available for
future reference.

WARNING: Playing loud music in an automobile
can permanently damage your hearing, as well as
hinder your ability to hear traffic. The maximum
volume levels achievable with Infinity speakers,
combined with high power amplification, may
exceed safe levels for extended listening. We
recommend using low volume levels when
driving. Infinity accepts no liability for hearing
loss, bodily injury or property damage as a result
of use or misuse of this product.

Depending on the size of the vehicle’s interior lis­tening space, reproduced bass frequencies below
80Hz are boosted by nearly 12dB per octave as
frequency decreases in the car. NOTE:This effect,
known as the vehicle’s transfer function, plays
an important part in shaping the overall in-car
response and is displayed graphically along with
freespace response on the enclosed data sheet
for your Reference subwoofer.

Reference Series subwoofers are optimized
to perform best in small sealed, vented and
prefabricated bandpass enclosures. While
infinite-baffle mounting of Reference Series
subs is possible, power handling will be greatly
compromised because there’s no enclosed
volume of air to prevent the speaker’s cone
from moving past its limit. For this reason, we
do not recommend infinite-baffle mounting for
Reference Series subwoofers.

You should choose the enclosure you will use
based on the type of music you listen to, how
much amplifier power you will use for the
subwoofer and how much space inside the
vehicle you can devote to a subwoofer enclosure.

Because a sealed enclosure provides the most
control over the woofer’s movement, a woofer
mounted in a sealed enclosure will handle more
power than a woofer mounted in another
enclosure type. Sealed enclosures provide more
accurate sonic reproduction than other enclosure
types, so they are well suited to all types of
music. Sealed-enclosure construction is straight­forward and there are many prefabricated sealed
enclosures available. Optimum sealed enclosures
are always smaller than other types of enclosures
optimized for a particular speaker, so they require
the smallest amount of space inside the vehicle.

Vented enclosures provide better efficiency in
the 40Hz –50Hz range but this efficiency comes
at the expense of sound in the lowest octave
(below 40Hz) and at the expense of some control
and power handling. If you are using a small
amplifier, a vented box will provide more bass
output from less power. Vented enclosures are
also well suited to a variety of music types.

Because vented enclosures require the volume
of the enclosure and the size of the port to have a
specific relationship with the characteristics of the
woofer, the enclosure must be built exactly to the
specifications provided. While there are some
prefabricated vented boxes available, matching
a prefabricated box to a particular woofer is
difficult. If you wish to use a vented enclosure,
we strongly recommend having your authorized
Infinity dealer build it or verify that your design
is correct if you wish to build it yourself. An
optimum vented enclosure is always larger than
the optimum sealed box for the same woofer and
will require more space inside the vehicle.

Bandpass enclosures often provide the most
output available from any amplifier and
subwoofer combination at the expense of sonic
accuracy. If sheer SPL (sound-pressure level) is
what you desire most, choose a bandpass
enclosure. Bandpass-enclosure design is very
tricky and the aid of a computer and enclosure
design software is necessary. If you are an
experienced installer or have some woodworking
experience, you may wish to build the enclosure
described in the enclosure design sheet included
with this woofer. Fortunately, there are many
prefabricated bandpass boxes available and
they are all optimized to extract the most output
possible from any woofer. Bandpass enclosures
can be quite large and may require a lot of space
inside your vehicle.