Electro-voice FORCE SUB DATASHEET
Force Sub
• High-output dual 15 inch slotloaded woofer system designed to
complement the FORCE stage
system
• Integral passive-crossover filter
combined with unique acoustic
design allows for parallel operation with full-range systems for
added bass response
• 300 watts continuous powerhandling capability
• Top-mounted 1-3/8-inch stand
adapter
• 30 inch pole included for elevating EV FORCE full-range system
• Durable industrial-grade carpet
covering
Description
The Electro-Voice Force Sub is an 8-ohm,
dual-15-inch subwoofer system designed to
reproduce high impact bass program material from a small, compact, easily portable
enclosure. The Force Sub is intended for
use with the Electro-Voice Force full-range
stage system, and incorporates a built-in lowpass filter to allow parallel operation of both
systems from a single amplifier channel.
When connected in parallel, the combined
impedance is 4 ohms. Conventional
biamplified operation is also possible using
an active electronic crossover of 12, 18 or
24 dB per octave and a crossover frequency
between 80 and 125Hz. No internal wiring
change is required for biamp operation because the built-in first-order low-pass filter
is only effective above 125Hz. In either
mode of operation an active low-frequency
protection filter is strongly recommended to
reduce unwanted program content below
40Hz. (Bass guitar open low “E” is approx.
41.2Hz) These very low frequencies are not
only potentially damaging to the woofers,
they also waste massive amounts of amplifier power and cause needless distortion of
the upper frequencies.
As seen in the response curve (fig. 1 ), the
frequency response of the Force Sub is not
“flat” nor was it intended to be. The requirements of a subwoofer for live performance
are radically different from those of a typical living room. Most popular music is inherently bass-heavy, with most of that energy concentrated in the kick drum “thump”
region between 60 and 80Hz. Force Sub has
been designed for maximum output efficiency in exactly that range. The use of two
specially designed 15 inch woofers results
in 36% more cone area than a single 18 inch,
and the dual slot-load enclosure design is
derived from technology developed for the
Electro-Voice X-Array touring systems. It
should be noted that the frequency response
graph (fig.1 ) was measured in an anechoic
(whole space) environment. From a practical standpoint, this is a sort of “worst case”
measurement of low-frequency capability.
In actual use, sitting on the floor, the long
bass wavelengths will be reinforced by the
floor and the room boundaries and will result in more low bass output than the graph
implies, depending on the room and the
Force Sub’s position in it.
The Force Sub includes a top-mounted stand
adapter and a 30 inch pole mount for use
with the Force full-range system. Safety
concerns limit the use of a pole greater than
30 inches in length, but under no circumstances should the total height of all components exceed 80 inches.
Force Sub will handle a long term average
power input of 300 watts RMS and realworld peaks of over 600 watts. The input
connections are ¼ inch phone, but may also
be ordered with Neutrik NL4MP connectors
(Force Sub-E), which are recommended for
sustained high power operation.
Power handling.
To our knowledge, Electro-Voice was the
first U.S. manufacturer to develop and publish a power test closely related to real-life
conditions. First, we use a random-noise input signal because it contains many frequencies simultaneously, just like real voice or
instrument program. Second, our signal contains more energy at extremely high and low
frequencies than typical actual program, adding an extra measure of reliability . Third, the
test signal includes not only the overall “long
term average” or “continuous” level—which
our ears interpret as loudness—but also
short-duration peaks which are many times
higher than the average, just like actual program. The long-term average level stresses
the speaker thermally (heat). The instanta-
Force™ Sub
neous peaks test mechanical reliability (cone
and diaphragm excursion). Note that the sinewave test signals sometimes used have a
much less demanding peak value relative to
their average level. In actual use, long-term
average levels exist from several seconds on
up, but we apply the long-term average for
several hours, adding another extra measure
of reliability.
Force™ Sub
Specifically, the Force
™
Sub is designed
to withstand the power test described in
the ANSI/EIA RS-426-A 1980. The EIA
test spectrum is applied for eight hours. To
obtain the spectrum, the output of a whitenoise generator (white noise is a particular
type of random noise with equal energy per
bandwidth in Hz) is fed to a shaping filter
with 6-dB-per-octave slopes below 40 Hz
and above 318 Hz. When measured with
the usual constant-percentage bandwidth
analyzer (one-third-octave), this shaping
filter produces a spectrum whose 3-dBdown points are at 100 Hz and 1,200 Hz
with a 3-dB-per-octave slope above 1,200
Hz.
Amplifier Recommendations.
The power-handling capacity of the Force
Sub is 300 watts EIA (350 watts AES). For
biamp operation choose an amplifier of approximately 300 watts RMS per channel, full
20-20,000 Hz bandwidth at 8 ohms. For
passive operation (Force Sub and Force fullrange connected in parallel) the power capacity of the full-range system must be taken
into consideration. Remember that the Force
full-range has a lower power-handling capacity than the Force Sub, so above the Force
Sub’s 125 Hz low-pass filter frequency all
of the amplifier power is directed to the fullrange system. Only below 125 Hz is the
power shared between the two systems, with
the Force Sub getting the majority only on
the very lowest notes. Therefore, for passive operation select an amplifier whose continuous 8 ohm rating, full 20-20,000 Hz
bandwidth, is appropriately sized to the fullrange system (a nice size for the Force is approximately 200 to 300 watts RMS @ 8
ohms continuous power per channel) and
whose 4 ohm rating per channel is near the
total for both systems. This class of amplifier, especially if it also incorporates good
on-board limiters, provides plenty of power
where you need it down in the bass region
where both systems are drawing power in
short duration pulses, but not so much as to
seriously endanger the more delicate highfrequency components. An amplifier that
matches this description very well is the
Electro-Voice Q44, which is ideally suited
to powering a Force or a passively crossed
(parallel connected) Force and Force Sub
system in stereo. Using an active (electronic)
crossover, the Electro-Voice Q66 is an ideal
choice for powering up to four Force Subs.
WARNING: Under NO Circumstances
should ANY amplifier be used in Bridge
Mode. Bridging an amplifier results in abnormally high peak voltage levels that can
destroy your speakers.
Limited Warranty
Electro-Voice products are guaranteed
against malfunction due to defects in materials or workmanship for a specified period,
as noted in the individual product-line
statement(s) below, or in the individual product data sheet or owner’s manual, beginning
with the date of original purchase. If such
malfunction occurs during the specified period, the product will be repaired or replaced
(at our option) without charge. The product
will be returned to the customer prepaid.
Exclusions and Limitations: The Limited
W arranty does not apply to: (a) exterior finish or appearance; (b) certain specific items
described in the individual product-line
statement(s) below, or in the individual product data sheet or owner’s manual; (c) malfunction resulting from use or operation of
the product other than as specified in the
product data sheet or owner’s manual; (d)
malfunction resulting from misuse or abuse
of the product; or (e) malfunction occurring
at any time after repairs have been made to
the product by anyone other than ElectroVoice Service or any of its authorized service representatives. Obtaining Warranty
Service: To obtain warranty service, a customer must deliver the product, prepaid, to
Electro-Voice Service or any of its authorized service representatives together with
proof of purchase of the product in the form
of a bill of sale or receipted invoice. A list of
authorized service representatives is available from Electro-V oice Service at 600 Cecil
Street, Buchanan, MI 49107 (800/234-6831
or FAX 616/695-4743). Incidental and
Consequential Damages Excluded: Product repair or replacement and return to the
customer are the only remedies provided to
the customer. Electro-Voice shall not be liable for any incidental or consequential damages including, without limitation, injury to
persons or property or loss of use. Some
states do not allow the exclusion or limitation of incidental or consequential damages
so the above limitation or exclusion may not
apply to you. Other Rights: This warranty
gives you specific legal rights, and you may
also have other rights which vary from state
to state.
Electro-V oice Speakers and Speaker Systems are guaranteed against malfunction due
to defects in materials or workmanship for a
period of five (5) years from the date of original purchase. The Limited W arranty does not
apply to burned voice coils or malfunctions
such as cone and/or coil damage resulting
from improperly designed enclosures. Electro-Voice active electronics associated with
the speaker systems are guaranteed for three
(3) years from the date of original purchase.
Additional details are included in the Uniform Limited Warranty statement.
For warranty repair, service information, or
a listing of the repair facilities nearest you,
contact the service repair department at:
616/695-6831 or 800/685-2606.
For technical assistance, contact Technical
Support at 800/234-6831 or 616/695-6831,
M-F, 8:00 a.m. to 5:00 p.m. Eastern Standard time.
Specifications subject to change without
notice.
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