Boston Acoustics 351 361 381 User manual

351
361
381
Designer Series
In-wall Speaker Systems

2
Specifications 351 361 381
Frequency Response (±3dB) 65–20,000Hz 57–20,000Hz 48–20,000Hz
Recommended Amplifier Power 10–100 watts 10–125 watts 10–150 watts
Nominal Impedance 8 ohms 8 ohms 8 ohms
Sensitivity [1 watt (2.83v) at 1m] 90dB 89dB 89dB
Tweeter Kortec 1" (25mm) Kortec 1" (25mm) Kortec 1" (25mm)
soft dome soft dome soft dome
Bass Unit 51⁄4" (135mm) copolymer 61⁄2" (165mm) copolymer 8" (200mm) DCD copolymer
Crossover Frequency 3500Hz 3400Hz 3200Hz
External Dimensions (HxW) 91⁄2x63⁄4" (241 x 171mm) 109⁄16 x73⁄4" (268 x 197mm) 123⁄8x 99⁄16" (315 x 243mm)
Mounting Hole Cutout (HxW) 83⁄4x53⁄4" (223 x 146mm) 97⁄8x71⁄8" (251 x 181mm) 113⁄4x 81⁄2" (298 x 216mm)
Mounting Depth (from surface) 25⁄8" (67mm) 27⁄8" (73mm) 31⁄4" (83mm)
Introduction
The Designer Series in-wall speakers are designed to be as accurate, clean and musical as our free-
standing speakers. The unobtrusive, flush-mount design makes them ideal for installation in walls
or ceilings of rooms where space or decor make conventional speakers undesirable or inappropri-
ate. They can also be used for front and/or rear channels in a home theater system.
The front surface has a matte white finish. The speaker can be installed as is, or can be painted to
match the room environment by using the supplied painting mask. The epoxy-painted, galvanized
steel speaker grille is removable.
The speakers are constructed of rugged materials suitable for use in a variety of environments,
indoors or out. Offering complete placement flexibility, all exposed components are moisture-,
rust-, and temperature-resistant for worry-free installation in the bath, kitchen or on the patio.
Their smooth, detailed sound comes from two highly refined driver elements: a powerful, long-
excursion copolymer bass unit and our 1-inch (25mm) Kortec™soft dome tweeter. The silk-like
fabric dome delivers a remarkably accurate response for outstanding clarity and articulation. The
tweeter and bass unit are mounted close together in a point-source configuration for excellent
imaging and extremely broad, uniform dispersion. This is important, because wide dispersion gives
you the flexibility to install the speakers where they look the best (high on the walls, for example),
yet still project a smooth, natural sound throughout the listening area.
In combination, these advanced engineering technologies and Boston’s state-of-the-art manufac-
turing facilities give the Designer Series a level of performance unmatched by other in-wall speakers.

3
Installation Instructions
NOTE: This manual assumes the installer possesses skill in the proper use of hand and power
tools, a knowledge of local building and fire codes and a familiarity with the environment behind
the wall or ceiling in which the speakers will be installed.
Quantity Description
2 Designer Series Speakers
2 Mounting Bracket
2 Barrier Cloth
2 Painting Mask
2 Metal Grille
1 Template
1 Owner’s Manual/Installation Instructions
1 Hardware Package*
Examine the contents of the package and verify that it contains the following:
Loudspeaker Side View Mounting Bracket Mounting Hole
351
361
381
91⁄2"
(241mm)
95⁄8"
(143mm) 83⁄4"
(223mm)
10 9⁄16"
(268mm)
101⁄2"
(267mm) 97⁄8"
(251mm)
123⁄8"
(315mm)
123⁄8"
(315mm)
113⁄4"
(298mm)
63⁄4"
(171mm)
25⁄8"
(67mm) 55⁄8"
(143mm) 53⁄4"
(146mm)
73⁄4"
(197mm) 27⁄8"
(73mm) 611⁄16"
(170mm)
71⁄8"
(181mm)
99⁄16"
(243mm) 31⁄4"
(83mm) 89⁄16"
(218mm)
81⁄2"
(216mm)
Quantity Description
Hardware package* contents:
12 8-32 x 2" screw
2 Cable clamp – 3⁄16"
* If the hardware package is missing any items, or is not found,
additional packages are available from Boston Acoustics.

4
Placement
Since the speaker installation is permanent and the furniture placement may not be, the user
should first determine the best long-term location — one that will accommodate future relocation
of the furniture in the room, while still allowing for an unobstructed sound path from the speakers
to the listening area.
Within reason, wherever the speakers look
right is where they’ll sound right. For best
results, place the speakers 6–10 feet
(1.8–3.3m) apart, so they form a triangle
with the main listening area. Try to keep the
speakers at least 12–18 inches (30–45cm)
from the nearest reflective surface (side
walls or ceiling). When used near a color
television, the speakers should be mounted
a minimum of 6 inches (150mm) from the
TV to avoid interference with the picture.
As a final check on the suitability of the
mounting location, it’s a good idea to
temporarily place a pair of small box
speakers, if available, at the mounting
locations chosen for the system. This will
give the listener an approximate idea of
what the speakers will sound like in that
location. Listen for pleasing stereo image,
realistic stage height or balanced surround-
field coverage (if using the speakers as rear-
channel surrounds). Note if any objects in
the room impede the sound path from the
speakers to the listening area.
Outdoor Use
The Designer Series is moisture- and
temperature-resistant and may be used
outdoors or in a marine setting. Placement
under the eaves of a roof or in the cockpit
of a boat reduces exposure to constant
direct sunlight, precipitation and salt spray,
thereby maximizing the speaker’s life.
12-18 inches
(30-45cm)
6-10 feet
(1.8-3.3m)

Painting the Speakers
If you intend to paint the speakers, it’s best to
do so before installation.
1. Remove the speaker grille. Carefully pry at
each corner with an awl or small screwdriver.
2. Use the form-fitting painting mask provided
to paint the housing. Cover the slots with
masking tape.
3. After painting, remove the mask by carefully
inserting a screwdriver into the slots. Do not
puncture the drivers behind the mask with the
screwdriver.
4. When painting the grilles, be certain that the
paint does not fill the perforated holes in the
metal. If using spray paint, use two thin coats.
If using house paint or other canned paint, thin
the paint to avoid filling the holes.
Be sure to use appropriate exterior paint for
outdoor applications.
5
Boston
Boston
Boston
Boston
Use masking tape
to cover slots.

6
Preparing for Installation
Map out the wiring paths from the speakers to the amplifier. We recommend 18-gauge wire for
runs up to 25 feet, and 16-gauge or thicker for longer runs. Be sure the speaker wire does not rest
or rub against any sharp or pointed objects.
The speakers should be mounted on a flat surface to form a good seal between the speaker flange
and the mounting surface.
Each speaker is 8 ohms nominal. When connecting more than two speakers per amplifier channel,
you should use series/parallel wiring or line transformers. In all cases, make certain that the total
impedance does not fall below the amplifier’s minimum rating. If you are not sure, contact your
Boston Acoustics dealer.
Use the cable clamp supplied to secure the speaker wire to the housing. Affix the clamp to one of
the screws used to hold the printed circuit board to the housing.
You Will Need
1. A utility knife, electric jigsaw or other means of cutting a hole in the mounting surface.
2. Phillips and flat-blade screwdrivers.
3. A wire cutter or stripper for preparing the speaker wires.
4. An awl or small screwdriver to remove the speaker grille.
With the hardware supplied, the speaker can be installed in existing walls and ceilings from 3⁄8"
(9.5mm) to 11⁄2" (38mm) thick. For thinner walls, you will need to use spacers (not provided) for the
mounting bracket. In walls greater than 11⁄2" (38mm) thick, you will need longer screws.
Installation
1. Make a cutout using the supplied template.
2. Run wire from the amplifier to the cutout. Allow an extra foot of wire
at the cutout. Strip 1⁄2" (12mm) off wire, and tightly twist the wire strands.
BostonAcoustics
351
HOLE CUTTING TEMPLATE
Cut hole to exact size of template. For details, see page 6 of installation instructions.
BostonAcoustics
361
HOLE CUTTING TEMPLATE
Cut hole to exact size of template. For details, see page 6 of installation instructions.
BostonAcoustics
381
HOLE CUTTING TEMPLATE
Cut hole to exact size of template. For details, see page 6 of installation instructions.
83⁄4"
(223mm)
53⁄4"
(146mm) 71⁄8"
(181mm) 81⁄2"
(216mm)
97⁄8"
(251mm) 113⁄4"
(298mm)

3. Remove speaker grille. Carefully pry each corner
with an awl or small screwdriver.
4. Prepare the speaker/bracket assembly for instal-
lation as shown.
For new construction, an optional bracket
(Model 35UB for the 351, Model 36CB for the 361,
Model 38B for the 381) is available from your
Boston Acoustics dealer.
5. Route the speaker wire through the cable clamp
and connect the wire to the speaker.
WARNING: To prevent electrical shock hazard,
always switch off the amplifier or receiver when
making connections to the speaker.
IMPORTANT: Typically, one side of the wire is
smooth. Connect this side to the –(black) speaker
terminal. The other side has a rib or stripe. Connect
this to the +(red) speaker terminal. Connect wire
at the amplifier in the same way. Failure to do so
will result in degraded sound.
6. Install speaker according to diagram below.
IMPORTANT: Do not overtighten screws. Doing so
will break the frame and/or make it impossible to
insert the grille.
7
Install barrier
cloth for ceiling
installations.

Listening Levels and Power-Handling
The power recommendation for the speakers assumes that you will operate the amplifier in a way
that will not produce distortion. Even our rugged speakers can be damaged by an amplifier if it is
producing distortion.
If you hear a harsh, gritty noise, turn down the volume. Prolonged or repeated operation of your
speaker with a distorted signal from the amplifier can cause damage that is not covered by the
warranty.
Limited Warranty
For one year from the date of purchase, Boston Acoustics will repair for the original owner any
defect in materials or workmanship that occurs in normal use, without charge for parts and labor.
Your responsibilities are to use the system according to the instructions supplied, to provide safe
and secure transportation to an authorized Boston Acoustics service representative and to present
proof of purchase in the form of your sales slip when requesting service.
Excluded from this warranty is damage that results from abuse, misuse, accidents, shipping, or repairs
or modifications by anyone other than an authorized Boston Acoustics service representative.
This warranty is void if the serial number has been removed or defaced.
This warranty gives you specific legal rights, and you may also have other rights which vary from
state to state.
If Service Seems Necessary
First, contact the retailer from whom you purchased the speakers. If that is not possible, write to:
Boston Acoustics, Inc., 300 Jubilee Drive, Peabody, MA 01960.
We will promptly advise you of what action to take. If it is necessary to return your speaker to the
factory, please ship it prepaid. After it has been repaired, we will return it freight prepaid in the U.S.
and Canada.
300 Jubilee Drive
Peabody, MA 01960
508-538-5000
Kortec is a trademark and Boston and Boston Acoustics
are registered trademarks of Boston Acoustics, Inc.
Specifications subject to change without notice.
© 1996 Boston Acoustics, Inc.
42-353-4