User Guide

Sealed enclosures are also very commonly used for
guitar—for some very good reasons. Like open-backed
enclosures, sealed enclosures are very easy to design
and build. The EVM12L loudspeaker performs very well
in virtually any possible sealed enclosure, from 0.9 to
3.0 ft
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(internal volume). The enclosure size makes
very little difference within this range. EVM12L
loudspeaker performance in sealed enclosures is tight
and punchy. The low end is fast and solid. The overall
performance is very focused.
Vented Enclosures
The most extended and contoured low-frequency
performance with the least amount of distortion is
typically realized in properly designed vented
enclosures. In such designs, the vent, or port, actually
reproduces the lowest octave or so of bass response.
The vent is driven to full acoustic output by a relatively
small motion of the speaker cone itself, acting through
the air contained within the enclosure. The excursion
of the EVM12L loudspeaker at these frequencies is
much reduced compared to sealed or open-backed
enclosures, directly reducing harmonic distortion.
INSTALLATION
The EVM12L loudspeaker may be front- or rear-
mounted, although front mounting is preferred
because of convenience. It is important that
recommended baffle openings and mounting hole
locations be followed.
Front Mounting
Front mounting requires a 279-mm (11.0-in.) diameter
cutout and a 294-mm (11.56-in.) bolt circle. Mark the
baffle opening and screw locations on the blank panel
first. Drill the screw holes before cutting the large
baffle opening. If 1/4-20 screws are used, four screws
are sufficient for secure mounting of the speaker. T-
nuts are recommended for simple, secure mounting. If
T-nuts are used, the holes should be 7.1-mm (0.281-
in.) diameter (letter “L” drill). Apply glue to the flanges
of 1/4-20 long shank T-nuts before driving into the rear
of the holes. Length of the 1/4-20 screws should be
1/2-inch plus the panel thickness when using T-nuts.
The screws must be fillister head or internal hex drive
machine screws to seat down in the recess of the
speaker frame gasket. Screws should be tightened
evenly and securely. Maximum torque possible with a
proper size screwdriver should be sufficient.
Fillister-head screw (left) and internal hex-drive machine
screw (right) for front mounting (not to scale)
!
Caution!
When front mounting, the screw head must fit
down into the front gasket cutout.
Front mounting detail (Not to scale)
Rear Mounting
Rear mounting requires the same diameter cutout and
screw circle as front mounting. Other comments
regarding the use of T-nuts apply to rear mounting as
well. Screw length should be 3/4-inch plus panel
thickness if using T-nuts—longer for standard hex nuts.
If hex nuts are used, a second nut should be tightened
against the first nut to prevent loosening during
operation. A lock washer and flat washer are
recommended between the screw head and frame.
Rear mounting detail (Not to scale)
Screws should be tightened evenly, but not
excessively. Maximum torque possible with a proper
size screwdriver should be sufficient. Do not use
adhesive-back gasket segments for rear mounting.
Normal fasteners up to 6 mm (1/4 in.) will fit through
the eight holes in the frame.
Custom Enclosures
If a cabinet is to be constructed from scratch, 3/4-inch
solid and jointed or marine plywood is recommended.
After construction, be certain interior is completely
free of metal filings, wood chips, etc.
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