-5- ULTIMATE PERFORMANCE SUBWOOFERS & MIDBASS
-4- ULTIMATE PERFORMANCE SUBWOOFERS & MIDBASS
BRAVOX ULTIMATE PERFORMANCE SUBWOOFERS have Thiele/Small parameters more suitable for operation in closed enclosures, but can
also provide good results when installed in vented enclosures (SVC models only). While it is possible for the advanced installer to use the
Thiele/Small parameters provided in the chart at page 2 to design their own enclosures (for more on “doing it yourself”, check out Vance
Dickason’s Loudspeaker Design Cookbook, 6th Edition at www.audioXpress.com), all this work has been done for you and provided in the
recommended enclosure charts. The choice of which type of enclosure, vented or sealed, is strictly up to you. As a rule, sealed enclosures
provide better transient (read that “quicker”) bass response than their vented counterparts, although the vented enclosures generally provide more
deep bass. Your choice should be based on the amount of space available and the size of the vehicle. In general, smaller vehicles (Corvettes to
Camry’s) probably work best with sealed enclosures while larger vehicles such as SUV’s, Vans, large trucks or RV’s can benefit from the kind of
performance available from vented enclosures. However, both enclosure types will work in any situation.
This enclosure is made up of a totally closed, air-tight box. This type of enclosure gives excellent, tight bass response, as well as providing an
effective control of loudspeaker excursion, maintaining it within reasonable limits and generally providing lower distortion and very high volume
levels. If you build your own enclosure, BRAVOX recommends that you glue and screw all joints using enough glue to ensure that all joints are
air-tight.
Vented enclosures are not air-tight and incorporate an additional opening known as a port or vent, which is generally fabricated from either
plastic or cardboard tubing. The port augments the sound coming out of the woofer and is in most cases capable of going lower in frequency
than the same woofer in a sealed box. Even though vented enclosures are not air-tight, you should follow the same procedure as with sealed
boxes and glue and screw together all joints.
Table in page 6 shows the internal volume (Vb) in liters and cubic feet for sealed and vented enclosures, specifically designed for ULTIMATE
PERFORMANCE SUBWOOFERS. For sealed enclosures there are options for normal and for “enhanced” bass response (note: the normal
response enclosure provides more accurate bass while the smaller “enhanced” bass enclosures are somewhat less accurate, but have marginally
increased power handing). Intermediate volumes to those shown on the table may also be used, with corresponding results between a normal
response and one with enhanced bass response. For vented enclosures there are two options for normal and “enhanced” bass response, but in
this case, rather than changing the volume of the enclosure, a different tuning (vent length) is used.
The dimensions shown in the tables are intended as a guideline and specific dimensions (HxWxD) may be changed provided the internal
volume of the enclosure is maintained. Please note that the internal volumes shown in the table already take in account volume occupied by
driver and port. For best performance the walls of the enclosure should be rigid and not vibrate as a result of the internal pressures generated by
the loudspeakers. BRAVOX recommends constructing enclosures from medium-density fiberboard (MDF) with a minimum thickness of 3/4”. For
larger 12” and 15” subwoofers it is desirable to use 1” thick MDF. In larger enclosures over 1 cubic foot, internal bracing that joins opposite
walls can be incorporated and the final enclosure should be as rigid as possible. All joints should be glued and fastened with screws.
Additionally, internal joints can be covered with a small bead of silicone adhesive to ensure that the enclosure is completely air-tight. ULTIMATE
PERFORMANCE SUBWOOFERS are all moderately heavy for their size and should be fastened to the enclosure with self-threading screws with
adequate length and diameter, utilizing all the mounting holes in the frame. To avoid air leakage, a foam rubber gasket or similar sealing method
should be applied between the loudspeaker and the enclosure. The external surface of the enclosure may be painted or fabric-covered, to suit
the consumer.
Since low frequency sounds are not directional, subwoofer enclosures can generally be placed anywhere within the car, without compromising
stereo imaging. While the trunk is the most obvious location, locating them behind the seats is another possibility. However, different
placement locations of subwoofer enclosures can sometimes influence the overall quality of bass/midbass response. As interior acoustics are
different for each vehicle, you may wish to experiment with various mounting locations before permanently mounting the woofer.
VENTED (BASS REFLEX) ENCLOSURES
SEALED ENCLOSURES
CONSTRUCTION AND INSTALLATION
INSTALLATION - ENCLOSURES
