Integrating The 12.1 Subwoofer; Installation Examples; Using The 12.1 In Passive Mode; Crossover Frequency And Impedance - Electro-Voice EViD 3.2 Owner's Manual

Installation Examples

The EVID™ Series is a product family with
the flexibility to fit the requirements of
many different applications. Listed below
are some suggested combinations for sys-
tems using the 12.1.
•
Rich, full-sounding low-level background
music and paging in a quiet restaurant,
office, or retail space: two EVID™ 3.2s in
parallel on each output of a 12.1.
•
Moderate-level music and paging in a
sports bar/restaurant or upbeat retail
space: two EVID™ 4.2s in parallel on
each output of a 12.1.
•
Higher-level foreground music in bass-
heavy applications such as dance floors,
amusement arcades, or loud bars: use
one EVID™ 6.2 on each output of a 12.1.
EVID™ systems may be used together.
For example, a large hotel might use eight
3.2s and two 12.1s in the dining room,
eight 4.2s and two 12.1s in the lounge, four
6.2s with two 12.1s surrounding the dance
floor, 6.2s around the pool, 6.2s or 4.2s
with or without 12.1s in the lobby, and 3.2s
in the corridors.
Crossover Frequency and
Impedance
The EVID™ 12.1 is designed to be used as a
passive subwoofer. No additional amplifiers
or signal processors are required to achieve
full benefit of the 12.1's performance. The
built-in passive stereo crossover sends the
lowest notes of both stereo channels to the
12" dual-coil bass driver and reduces the
amount of low frequencies sent to the satel-
lite speakers. This allows them to play loud-
er and cleaner while presenting a more even,
amplifier-friendly impedance load than if all
the speakers were connected in parallel.
The EVID™ 12.1's crossover tunes a com-
bination of electrical and acoustic character-
istics to complement the response of the
full-range EVID™ models. The crossover
point is set electrically in the 160Hz range
with a topology that enables the nominal
12
Appendix A: Integrating the Subwoofer
system impedance to be determined by the
number of satellites per channel.
Using a Separate Amplifier
Channel for the 12.1
In certain specialized applications, it may be
desirable to drive the subwoofer with a sep-
arate amplifier channel. In these applica-
tions the active crossover point must be at
or below 160Hz so as not to interfere with
the built-in passive crossover. Both sections
(left and right inputs) must be connected in
parallel (4 ohm system impedance) when
operating as a mono device. No load resis-
tors are necessary on the hi-pass outputs.
Characteristics of All
Subwoofers
While subwoofers do radiate sound omnidi-
rectionally (in all directions) and the sound
is generally non-localizable (one can't hear
exactly where it comes from), subwoofer
sound level still drops off the farther one
moves from the subwoofer. The highest out-
put and best room loading are accomplished
with the subwoofer mounted in a corner at a
three-boundary junction (wall/wall/ceiling or
wall/wall/floor, an arrangement also referred
to as 1/8 space). Mounting at a two-boundary
junction (wall/ceiling, or 1/4 space) produces
three dB less output, and mounting in the
middle of a room in the ceiling (1/2 space)
reduces output still another three dB.
Subwoofers produce large amounts of long-
wavelength low-frequency energy. Every
object has its own resonant frequency, and
long wavelengths tend to excite large objects
(like walls, floors, doors and ceiling panels).
Anything loose in or on a ceiling or wall will
buzz or rattle as a subwoofer's level is
increased. Most of these can be isolated and
fixed with small, strategically placed bits of
foam tape. Others may require driving addi-
tional nails or screws and perhaps some
caulking to dampen their sympathetic move-
ment. Be aware that as bass levels increase,
so does the likelihood of rattles and buzzes.
EVID Owner's Manual