811W, 1011W, 1211W
®
R EFERENCESERIES
INSTRUCTIONS
Thank you for choosing an Infinity Reference Series sub-
woofer. 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 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 automotive
environment 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.
A FEW WORDS ABOUT ENCLOSURES
Your Reference Series subwoofer
requires an enclosure to realize its full lowfrequency response. The speaker’s design is
flexible enough to produce exceptional
results no matter whether you specify a
small sealed, vented or bandpass enclosure. In vented and bandpass enclosures,
box size and port tuning frequency will also
help dictate the low-frequency performance
and output capability of your system.
Your Reference Series subwoofer will
also work in infinite baffle applications
where there is no space or budget to build
a box. Be aware that infinite baffle or “free
air” mounting will reduce the power handling of any subwoofer compared to an
application using an enclosure.
Finally, any deviation from recommended
enclosure volumes or port dimensions
should be made using dedicated enclosuredesign software. If this type of software is
not available to you, ask your authorized
Infinity dealer for help.
YOUR CAR AND BASS REPRODUCTION
Depending on the size of the vehicle’s
interior listening space, reproduced frequencies below 80Hz are boosted by nearly
12dB per octave in the car as frequency
decreases. 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.
ENCLOSURE CALCULATIONS AND
BUILDING BOXES
Use the recommended box designs on
the enclosed data sheet. Choose cabinet
dimensions to fit your vehicle, but do not
change the enclosure’s volume. Doing so
will change the tuning frequency of the
enclosure and may adversely affect final
performance. If you cannot perform the
necessary calculations yourself, please contact your authorized Infinity dealer for help.
In addition, there are a number of points
you’ll want to keep in mind as you construct an enclosure:
1. Use 3/4" (19mm) MDF (medium-density
fiberboard) or marine birch wood to build
an enclosure. Enclosures for 12" and larger
subwoofers, or small subwoofers driven by
high-power amplifiers, should be constructed using 1" (25mm) material.
2. Seal all joints with glue and screws; do
not use nails. We recommend "deck", "zip"
or drywall screws since they have coarse
threads for better grip and don’t require
pre-drilling holes. Once the box has been
tested, seal all interior joints with silicone
caulk.
3. Depending on the application, fill the
enclosure according to the design you have
chosen from the enclosed data sheet in one
of three ways: zero-percent fill (i.e., no fill),
50-percent fill (i.e., 1"-thick polyfill sheets on
all inside walls except where subwoofer is
mounted), or 100-percent fill (i.e., entire box
is stuffed with loosely packed polyester
fiberfill).
4. Use PVC or ABS pipe for ports. Keep in
mind the openings at either end of the port
must be at least one port diameter away
from any obstructions, including filling
material inside the box. Rectangular vents
can be used as long as the cross-section
surface area matches the recommended
port-area values in the enclosed data sheet.
5. When using vented boxes, we recommend using a subsonic filter (like the DBO™
feature found on Kappa Series power
amplifiers) to limit the power sent to the
speaker at frequencies below, the enclosure’s port tuning frequency, thus limiting
the speaker’s excursion.
POWER-HANDLING LIMITATIONS
SPECIFICATIONS
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 larger than the Vas of the
subwoofer, it will perform as if it were in
an infinite baffle installation.
Vented 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 port tuning range, 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 squarewave,
contains nearly twice the power of a clean
sine wave at the same level. Bass that
sounds broken up and distorted at higher
volumes usually indicates that the amplifier
is clipping (i.e., being asked to deliver
power beyond its rated power).
• Infinite baffle or “free air” mounting
applications allow for greater cone excursion than subwoofers mounted in an enclosure. In order to compensate, recognize
that the power-rating value 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 recommended 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.
Reference 811w
Configuration: 8" woofer
Nominal Impedance: 4 ohms
Power Handling: 200W
Sensitivity @ 2.83V/1m: 91dB
Frequency Response: 50Hz – 1kHz
Mounting Depth: 4-3/8" (112mm)
Cut-out Diameter: 7-1/8" (181mm)
Reference 1011w
Configuration: 10" subwoofer
Nominal Impedance: 4 ohms
Power Handling: 225W
Sensitivity @ 2.83V/1m: 92dB
Frequency Response: 40Hz – 500Hz
Mounting Depth: 4-5/8" (118mm)
Cut-out Diameter: 9-1/8" (232mm)
Reference 1211w
Configuration: 12" subwoofer
Nominal Impedance: 4 ohms
Power Handling: 250W
Sensitivity @ 2.83V/1m: 93dB
Frequency Response: 30Hz – 500Hz
Mounting Depth: 5" (127mm)
Cut-out Diameter: 12-1/8" (308mm)
Declaration of Conformity
We, Infinity Systems A/S
Kongevejen 194B
DK-3460 Birkerød
DENMARK
declare in own responsibility, that the products described
in this owner’s manual are in compliance with technical
standards:
EN 50 081-1/1992
EN 50 082-1/3.1995
Steen Michaelsen
Infinity Systems A/S
Birkerød. DENMARK. 3/98
Infinity Systems, Inc. • 250 Crossways Park Drive,
Woodbury, NY 11797 USA • (516) 496-3400 • FAX (516) 682-3583
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