Infinity reference series User manual

reference series
1020w,1220w
Thank you for choosing an Infinity Reference Series
subwoofer. Reference Series subwoofers are designed to suit a
broad range of mobile-audio 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 and 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.
instructions
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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.
YOUR CAR AND BASS REPRODUCTION
Depending on the size of the vehicle’s interior lis-
tening 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.
CHOOSING AN ENCLOSURE
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.

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POWER-HANDLING LIMITATIONS
The power-handling capability of any woofer is
related to both its ability to dissipate heat and the
maximum excursion limits of its cone. Once the
speaker’s voice coil moves outside the magnetic
gap, power can no longer be converted into
motion and all the amplifier’s power is converted
into heat in the voice coil.This voice-coil heating
is the largest detriment to speaker longevity, so
overexcursion should be avoided. Since speaker-
cone excursion is different for each type of
enclosure, power handling is different for each
enclosure.
Sealed enclosures exert the most control over
the motion of a subwoofer because the air inside
the box acts like a spring against the motion of
the woofer cone. Larger boxes allow for more
excursion, thus providing more low-frequency
output for the amount of power used.When
placed in a sealed box much larger than theVas
of the subwoofer, it will perform as if it were in
an infinite-baffle installation.
Vented and bandpass enclosures have the lowest
amount of excursion for the amount of sound
output.This is a result of port output reinforcing
the sound output from the woofer.The mass of
the air contained in the port provides an acoustic
load on the woofer’s cone at the tuning frequency,
and this added mass decreases woofer-cone
excursion. Vented boxes do not provide adequate
woofer control when driven below the tuned
frequency (Fb), so proper design is important. A
vented bandpass box will have the lowest overall
cone excursion provided a subsonic filter is used.
•Voice-coil overheating and burning due to
overexcursion are often caused by overdriving
an amplifier into “clipping.”A severely clipped
signal, or square wave, contains nearly twice
the power of a clean sine wave at the same level.
Bass that sounds broken up and distorted at
higher volumes is usually indicative of an
amplifier that is clipping and being asked to
deliver power beyond its ability.
•Infinite-baffle or “free-air”mounting applica-
tions allow for greater cone excursion than
subwoofers mounted in an enclosure. In order
to compensate, the power handling of the
subwoofer will likely be half its rated power
in this application.
•Study the excursion curves on the enclosed
Reference Series data sheet and note the
differences for different enclosure applications.
The type and size of box used will produce
different excursion demands on the enclosed
subwoofer and, consequently, different
levels of power handling. As long as the
recommended enclosure parameters are
used, the subwoofer will perform properly
in its enclosed environment. However, any
design deviation may result in less than
optimum performance, and may also subject
the subwoofer to overexcursion (i.e., where the
voice coil leaves the gap) that can eventually
damage the speaker. For additional help with
this issue, please contact your authorized
Infinity dealer.
SPECIFICATIONS
Reference 1020w
Configuration: 10" subwoofer
Nominal Impedance: 4 ohms
Power Handling: 250W RMS/1000W peak
Sensitivity @ 2.83V/1m: 90dB
Frequency Response: 22Hz –800Hz
Mounting Depth: 5-1/2" (140mm)
Cutout Diameter: 9-1/4" (235mm)
Reference 1220w
Configuration: 12" subwoofer
Nominal Impedance: 4 ohms
Power Handling: 300W RMS/1200W peak
Sensitivity @ 2.83V/1m: 92dB
Frequency Response: 20Hz –800Hz
Mounting Depth: 6-1/8" (156mm)
Cutout Diameter: 11-1/8" (283mm)

DECLARATION OF CONFORMITY
We, Harman Consumer International
2, route de Tours
72500 Chateau-du-Loir
France
Lutz Uphoff
Harman Consumer International, 1/00
declare in own responsibility, that the products described in this owner’s manual are in compliance with technical standards:
EN 55013/A12/8.1994
EN 55020/12.1994
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Infinity Systems, Inc. •250 Crossways Park Drive,Woodbury, NY 11797 USA
[phone] •FAX [phone] •www.infinitysystems.com
© 2000 Infinity Systems, Inc. •P/N: INFREF1020W/1220W Made in USA Printed in USA 1/00