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O
THER APPLICATIONS
MOUNTING SPEAKERS IN BOXES
Many people prefer to mount their component speakers into some sort of
enclosure in order to mimic that of a conventional home speaker system. We
support this concept because such an enclosure provides an acoustical "air
spring" for the woofer thus lowering distortion, increasing power handling, and
increasing the life of the speaker system. But, you must also supplement the
low frequency part of the music (below @ 100 Hz) with some kind of subwoofer
for an acoustically balanced audio system.
Although you can place your speakers into nearly any reasonable sized box,
the box technology dictates a sealed design because of inherent the "Thiele-
Small" parameters of the woofers. The woofers in our systems all have Qts
values near 0.7 which allows for a sealed box or a semi-infinite baffle door
speaker installation only. Attempting to design and vent a woofer box in any
way will only raise distortion, lower power handling, and shorten speaker life
while providing little or no additional bass response. In other words...don't
bother trying to make any unique vented box systems - they don't benefit this
type of speaker.
Please refer to the adjacent table for
recommended dimensions of an enclosure
keeping size to a minimum yet providing
good acoustical response. This table
shows suggested exterior dimensions
needed to achieve the interior air volumes
yet compensating for 3/4 inch wood panels
and interior speaker air volume
displacements. Other panel dimensions can
be used (e.g., an equal length cubic box)
but this is not recommended since the
lengths given here help prevent internal
standing wave induced frequency response
problems.
A
R
DDITIONAL
The following is a list of materials and sources of recommended reading for the person interested in loudspeakers,
acoustics, and audio in general. Subjective comments are noted for each.
DESIGNING, BUILDING, AND TESTING YOUR OWN SPEAKER SYSTEM, David Weems, Copyright 1984, TAB Books
#1964, Blue Ridge Summit, PA 17294. (This is an excellent introductory book on designing speakers for the home but is
quite applicable to the car since many concepts are carried over.)
LOUDSPEAKER DESIGN COOKBOOK, Vance Dickason, copyright 1991-1996, distributed by Old Colony Sound Lab,
Peterborough, NH, 03458. (A significant technical step up from Weems addressing complex woofer box and crossover
designs. Clearly a reference book useful for all.)
BLAUBOX WOOFER BOX DESIGN COMPUTER PROGRAM, Thomas Breithaupt, Blaupunkt div. Robert Bosch
Corporation, 2800 S. 25th Avenue, Broadview, IL 60153. (This is a simple to use IBM PC computer program used to
predict the frequency response of a subwoofer in 10 different enclosures including sealed, vented, and bandpass
configurations. Basic passive crossover designs are covered as well. It is provided free of charge as a download from
the Blaupunkt Internet site at: http://www.blaupunkt.com.)
R
ECOMMENDED SEALED BOX VOLUMES
(Exterior dimensions using 3/4" panels and speaker volume compensated)
MODEL
RECOMMENDED
VOLUME
f3 (Hz)
HEIGHT
WIDTH
DEPTH
I
EFERENCE
NFORMATION
ODc54
0.10 cu.ft.
110
10.0
7.0
5.5
– 9 –
ODc65
ODc66
0.13 cu.ft.
0.15 cu.ft.
100
90
10.5
11.5
8.0
8.5
5.5
5.5
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