Electro-Voice SB121 User manual

Description
The Electro-Voice Sb121 bass module is a
compact, low-frequency enhancement sys-
tem designed for sound reinforcement.
Throughtheextensiveuseofcomputer-aided
design and modeling, Electro-Voice engi-
neers have developed a state-of-the-art por-
table system that combines the advantages
of a long-throw 12-inch woofer in a high-
impact polypropylene structural-foam cabi-
net that is light in weight (only 32.2 lb over-
all).
Low-Frequency Driver Description
The DL12Sx low-frequency driver was spe-
cially developed for the Sb121. Its deep-
frame geometry provides high-peak excur-
sion ability. At the heart of this driver, is a
magneticstructureoptimizedtoyieldthebest
possible Thiele-Small parameters to match
the tuned enclosure.
The woofer features beryllium copper lead
wires,alow-massedge-woundvoicecoiland
high-temperature materials. The part of the
magnet structure adjacent to the coil is insu-
lated using the exclusive EV PROTEFTM
process (U.S. Patent #4,547,632). The coil
is driven by a massive, 16-lb magnet struc-
ture.
Enclosure Description
The enclosure is constructed of high-impact
polypropylene structural foam. It provides a
stiff and extremely durable enclosure.
Molded into the cabinet are an integral
carrying handle and a stand socket for
mounting on 13/8-inch stands such as the
100BK. Rubber feet that are attached to the
bottom of the cabinet and the mating sock-
ets that are molded into the top provide a
means of stacking systems. Four hanging
inserts are also provided (four metric M8 x
1.25).
Xp200A Electronic System Controller
TheoptionalXp200Aelectronic system con-
trollercomplementsthecharacteristics of the
Sb121. Its mono-summed subwoofer outputs
provide crossover and infrasonic protection
(see Crossover and Subpassband Protection
sections).Its 24-db-per-octave filters roll-off
response below 37 Hz and above 100 Hz.
TheXp200A also includes a special low-fre-
quency profile circuit that enhances the per-
formance of the Sb121. The amount of en-
hancement can be adjusted to suit the user’s
personal preference.
Crossover
The Sb121 should be used in conjunction
with an active crossover to roll-off response
above100-200 Hz, so that bass enhancement
does not “muddy up” vocals or call atten-
tion to the physical location of the Sb121.
(The closer the roll-off point is to 100 Hz,
the least the overall sound quality will be
affected by the enhancement of the bass
module.) The roll-off rate should be a mini-
mum of 12-dB per octave.
The optional Xp200A electronic controller
provides a 24-dB-per-octave roll-off above
134 Hz.
Subpassband Speaker Protection
The Sb121, like all other vented systems,
experiences rapidly increasing cone excur-
sion below the box-tuning frequency (60 Hz
for the Sb121). Acoustic output is also de-
creasing rapidly. Therefore, it is sensible to
protect the Sb121 and maximize its undis-
tortedoutput by inserting an active high-pass
filter at a corner frequency somewhat below
boxtuning.Theroll-offrateshouldbeatleast
12-dB per octave. At this minimum rate, a
corner frequency of about 0.8 the box tun-
ing frequency (48 Hz for the Sb121) is ap-
Sb
121
300-Watts Nonpowered
Bass Module
• Lightweight (32 lb) and compact
• Very durable structural-foam
enclosure with integral handle
• Stand mountable and arrayable
• 300-watts continuous power
handling (1,200-watts short term)
for high output
• DL12Sx 12-inch woofer with Kevlar®
Reinforced cone
• Neutrik Speakon®high-current
connectors (1/4-in. phone jacks also
provided)
• Four molded-in attachment points
(metric M8 x 1.25) for secure
suspension

Sb121 300-Watt Nonpowered Bass Module
S
b
121 300-Watt Nonpowered Bass Module
propriate.Forhigherroll-offrates,lowercor-
ner frequencies are permissible and provide
essentially equivalent protection.
The sub output of the optional Xp200A elec-
tronic system controller provides a 24-dB-
per-octave roll-off at 37 Hz.
Suspending Sb121 Enclosures
WARNING: Suspending any object is po-
tentially dangerous and should only be at-
tempted by individuals who have a thor-
ough knowledge of the techniques and
regulations of rigging objects overhead.
Electro-Voice strongly recommends that
theSb121 be suspended takinginto account
all current national, federal, state and lo-
cal regulations.Itis theresponsibility of the
installertoensuretheSb121issafelyinstalled
in accordance with all such regulations. If
the Sb121 is suspended, Electro-Voice
strongly recommends that the system be in-
spected at least once a year. If any sign of
weakness or damage is detected, remedial
action should be taken immediately.
A manual entitled Suspending System 200TM
Loudspeakers is included with every Sb121
system. It gives a summary of the suspen-
sion kits available and an idea of how each
kit is used. A brief overview, which illus-
trates some approaches for single and mul-
tiple suspension, is given here for the ben-
efit of the system designer. Please refer to
individual suspension kit engineering data
sheets for full details and safety information.
The first approach is to suspend an indi-
vidual Sb121 enclosure. The four metric
M8 x 1.25 inserts (see Figures 2 and 4)
which are built into the enclosure allow
the system to be suspended using eyebolts
(Mb100 eyebolt attachment kit).Typically
it will be necessary to attach two cables to
the top eyebolt and “pull up” on the rear. The
Mb200 bracket (see Figure 5) encompasses
the top and bottom of the enclosure and has
additional features to make suspending the
Sb121 easier and more flexible. Electro-
Voice recommends the use of the Mb200 in
all but the simplest situations. The Mb200
has supplementary holes to allow the Sb121
to be attached to a wall or ceiling and aimed
at an audience.
The Mb200 installation kit also allows the
use of OmniMount®Series 100 mounting
hardware by providing three-hole-pattern
groups compatible with these support sys-
tems.WhenOmniMount®Series100mount-
ing hardware is specified, the Mb200 instal-
lationkitmust first be attached to the speaker
enclosure.
The second approach is to suspend multiple
Sb121enclosures.TheSb121enclosureisnot
designed to suspend multiple enclosures
from itself. If an “array” is required, then
multiple Mb200’s must be used. Arrays may
beconstructedvertically by “daisy chaining”
two Mb200’s from each other. The Mb300
arraybracket allows the easy and secure con-
structionofhorizontalarrays, using Mb200’s
to support the enclosure.
Power-Handling Capacity
To our knowledge, Electro-Voice was the
first U.S. manufacturer to develop and pub-
lish a power test related to real-life condi-
tions. First, a random noise input signal is
used because it contains many frequencies
simultaneously, just like the real voice or
instrument program. Second, our signal con-
tains more energy at extremely high and low
frequencies than the typical program, add-
ing an extra measure of reliability. Third, the
test signal includes not only the overall
“long-termaverage”or“continuous” level—
which our ears interpret as loudness—but
also short-term peaks which are many times
higher than the average, just like the actual
program. The long-term average level
stresses the speaker thermally (heat). The
instantaneouspeaks test mechanical reliabil-
ity (cone and diaphragm excursion). Note
that the sine-wave test signals sometimes
usedhavea 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.
Specifically, the Sb121 is designed to with-
stand the power test described in the ANSI/
EIA RS-426-A 1980. The EIA test spectrum
isapplied for eight hours. To obtain the spec-
trum, the output of a white noise generator
(white noise is a particular type of random
noisewithequalenergyperbandwidthinHz)
is fed to a shaping filter with 6-dB-per-oc-
tave slopes below 40 Hz and above 318 Hz.
When measured with the usual constant-per-
centage bandwidth analyzer (1/3-octave),
this shaping filter produces a spectrum
whose 3-dB-down points are at 100 Hz and
1,200 Hz with a 3-dB-per-octave slope
above 1,200 Hz. This shaped signal is sent
to the power amplifier set at 300 watts into
the 6.3-ohm EIA equivalent impedance
(43.5-volts true rms). Amplifier clipping
sets instantaneous peaks at 6 dB above the
continuous power, or 1,200-watts peak
(86.9-volts peak). This procedure provides
a rigorous test of both thermal and mechani-
cal failure models.
Amplifier Power Recommendations
As noted in the Power-Handling Capacity
section,above,the Sb121hasarandom-noise
power capacity of 300-watts long term
(1,200-watts peak) per ANSI/EIA RS-426-
A 1980. The following guidelines will help
relate this number to an appropriate power
amplifier output rating.
1. To use the Sb121 to full capacity,
skilled experts in sound-system installation
and operation will obtain the best results if
the power amplifier is 2.0 to 4.0 times the
long- term average noise power rating of the
speaker system (600 to 1,200 watts).
The caution cannot be made
strongly enough, however, that this ar-
rangement is only for experts or for those
whocandisciplinethemselvesagainst“push-
ing” the system for ever-higher sound levels
and who can avoid “accidents” such as cata-
strophic feedback or dropped microphones.
2. A more conservative, “normal”
amplifier size, which will produce audible
results nearly equal to those of the “expert”
recommendation,is1.0 to 1.4 times the long-
term average noise power rating of the
speaker. For the Sb121 this is 300 to 420
watts.
3. To be very conservative, one can
use an amplifier rated at 0.5 to 0.7 times the
long-term average noise power rating of the
loudspeaker. For the Sb121 this is 150 to
210 watts.

S
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121 300-Watt Nonpowered Bass Module
Sb121 300-Watt Nonpowered Bass Module
Request P.A. Bible Addition No. Two
(“Power-Handling Capacity”) for more
background on these recommendations.
Sb121 Connections
The Sb121 is equipped with one Neutrik
Speakon®NL4MPandone1/4-in.phonejack
connected in parallel, a configuration which
allowsfordaisy-chainingofspeakersystems.
Additional Neutrik Speakon®NL4MP and
1/4-in.phonejacksaresuppliedformaximum
flexibility. Instructions on how to inter-
change the connectors are included with ev-
ery Sb121.
In continued high-power applications,
Electro-Voice recommends the use of the
Speakon connector. However, to provide a
high level of compatibility, the 1/4-in. phone
jacks are also provided. The Speakon
NL4MPwill mate to a NL4FC Speakoncon-
nector, which is a 4-pin connector. Figure 3
shows typical wiring configurations using
banana plugs or 1/4-in. phone jacks (the ba-
nana plug provides the more reliable con-
nection). Cable connections should be made
to the 1+ and 1– terminals only. Cables uti-
lizingtheSpeakonNL4FCareavailablefrom
your local dealer.
Multiple Use
The Sb121 may be used in multiples to in-
crease acoustic output. A 6-dB increase in
maximum acoustic output occurs when two
speaker systems are placed side by side and
paralleled (yielding a 4-ohm load). For op-
eration at very low frequencies, the woofer
cones “mutually couple,” acting as one sys-
tem with twice the effective cone area and
power-handling capacity. Efficiency is
doubled by the increased cone area to pro-
vide 3 dB more output, while the doubled
power capacity provides the potential for an
additional 3-dB gain in maximum acoustic
output.
Mutual coupling occurs when the center-to-
center distance between woofers is less than
one-half the wavelength. For the Sb121
crossed over at 100 Hz (the frequency pro-
vided by the optional Xp200A electronic
system controller), the maximum distance
for mutual coupling across the band is about
1.5 m (5 ft). When the woofers are spaced
greater than one-half the wavelength, the
level increase is limited to the 3-dB input-
power increase.
The Sb121 is connected using the connector
marked “input.” A parallel woofer can be
connected using the other jack. This halves
the impedance the amplifier “sees,” from
8 to 4 ohms. Caremustbetakennottoabuse
the amplifier by connecting impedances
which are too low (refer to amplifier speci-
fications).
Loudspeaker Response Due to the
Acoustical Environment
Several factors must be considered when de-
termining the overall response of a speaker
system in any listening environment. Physi-
cal characteristics of the room itself and
placement of the speakers and listener can
have considerable affect on SPL capability,
perceived and/or measured frequency re-
sponse and stereo imaging.
Thelow-frequencyresponseoftheSb121can
beadverselyaffectedbypoorplacement.The
Sb121wasdesignedforquarter-orhalf-space
use. This requires that the speaker system be
positionedascloseaspossibletofloororwall
surfaces (half space) or a floor/wall junction
(quarter space). Corner placement, in most
cases, will reinforce low frequencies the
most. Also, placement in loose cavities or
resonantmountingscanseriouslydegradethe
overall response.
Architects’ and Engineers’
Specifications
The loudspeaker system shall consist of a
12-inch long-throw low-frequency trans-
ducer mounted in a two-piece vented enclo-
sure made of black textured injection-
molded polypropylene structural foam.
The system shall exhibit a 50- to 500-Hz fre-
quency response with a sensitivity of no less
than 94 dB (1 watt /1 meter, 50- to 200-Hz
band-limited pink noise). It will be capable
of handling 300 watts of power by the test
described in the ANSI/EIA RS-426-A 1980.
Paralleled input and output connectors shall
be present, consisting of a combination of
NeutrikSpeakon®NL4MP and 1/4-in.phone
jacks. Four metric M8 x 1.25 attachment
points capable of supporting the system in a
permanent installation application shall also
be present.
The loudspeaker shall be have a black, per-
forated metal grille covering the woofer.
Overall dimensions shall be 586 mm (23.1
in.) high, 429 mm (16.9 in.) wide, 312 mm
(12.3 in.) deep. The weight shall be 14.6 kg
(32.2 lb).
The loudspeaker system shall be the
Electro-Voice Sb121.
Uniform limited Warranty
Electro-Voice products are guaranteed
against malfunction due to defects in mate-
rials or workmanship for a specified period,
as noted in the individual product-line
statement(s)below, orin the individual prod-
uct data sheet or owner’s manual, beginning
with the date of original purchase. If such
malfunction occurs during the specified pe-
riod, 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
Warranty does not apply to: (a) exterior fin-
ish or appearance; (b) certain specific items
described in the individual product-line
statement(s)below, orin the individual prod-
uct data sheet or owner’s manual; (c) mal-
function 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 EVI Audio
Service or any of its authorized service repre-
sentatives. Obtaining Warranty Service:
To obtain warranty service, a customer must
deliver the product, prepaid, to EVI Audio
Service or any of its authorized service rep-
resentatives together with proof of purchase
of the product in the form of a bill of sale or
receipted invoice. A list of authorized ser-
vice representatives is available from
EVI Audio Service at 600 Cecil Street,
Buchanan, MI 49107 (800/234-6831 or FAX
616/695-4743). IncidentalandConsequen-
tial Damages Excluded: Product repair or
replacement and return to the customer are
the only remedies provided to the customer.

S
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121 300-Watt Nonpowered Bass Module
Sb121 300-Watt Nonpowered Bass Module
Electro-Voice shall not be liable for
any incidental or consequential dam-
ages including, without limitation, in-
jury to persons or property or loss of
use. Some states do not allow the ex-
clusion or limitation of incidental or
consequential damages so the above
limitation or exclusion may not apply
to you. Other Rights: This warranty
givesyou specific legal rights, and you
may also have other rights which vary
from state to state.
Electro-Voice Speakers and Speaker
Systems are guaranteed against malfunc-
tion due to defects in materials or work-
manship for a period of five (5) years from
the date of original purchase. The Limited
Warranty does not apply to burned voice
coils or malfunctions such as cone and/or
coil damage resulting from improperly de-
signed enclosures. Electro-Voice active
electronicsassociatedwiththespeakersys-
tems are guaranteed for three (3) years
from the date of original purchase. Addi-
Figure 1 — Sb121 Frequency
Response (1 watt/1 meter, anechoic
environment)
tional 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 Techni-
cal 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.

S
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121 300-Watt Nonpowered Bass Module
Sb121 300-Watt Nonpowered Bass Module
Figure 3 — Two-Conductor Cable
Configurations for Sb121 Speaker
System using Neutrik Speakon®
NLF4C Four-Pin Connector
Figure 2 — Sb121 Dimensions
Figure 4 — Suspending Sb121 using the
Mb100 Eyebolt Attachment Kit
Figure 5 — Suspending Sb121 Using the
Mb200 Installation Kit
586 mm
(23.1 in.)
190 mm
(7.5 in.)
429 mm
(16.9 in.)
76 mm
(3.0 in.)
341 mm
(13.4 in.)
226 mm
(8.9 in.)
312 mm
(12.3 in.)
190 mm
(7.5 in.)