Electro-Voice MH660P User manual

MH660C
Coaxial Constant-
Directivity Horn System
.
.
.
60 degree vertical coverage angle
High-output high-quality music and
speech for stadiums and performing-arts
venues
Large, correctly sized horn mouths
provide uniform directivity control to
500 Hz, for Increased intelligibility under
difficult acoustic conditions
High “Q” for increased intelligibility
Suspension system for safe and easy
installation
DH2As2 2-inch compression driver for
extended high-frequency performance
Short throw/fill-in when used with the
very-large-format MH stadium horn
systems
SPECIFICATIONS
Typical AxialFrequency Response (swept
one-third-octave plnk noise, anecholc
envlronment, 4 volts at 10 feet, normalized
for 1 watt, 1 meter into mld-bass driver;
see Figure 1):
150-20,000
Hz
Low-Frequency 3-dB-DownPoint:
150 Hz
Usable Low-Frequency Limit (10-dB-down
point):
140 Hz
Recommended Crossover Frequencies:
160 Hz, 1,600
Hz
Crossover Slopes per Octave, Suggested:
24
dB
Recommended Signal Delay,
Mid Bass: 0.00 msec
High
Frequency: 0.60 msec
Long-Term Average Power-Handling
Capacity (see Power Handling section),
Mid Bass
(per ANSl/ElA RS-426-A):
300 watts
High Frequency
(per AES2-1984/ANSI S4.26-1984):
60 watts
Sensitivity (SPL at 1 meter, 1 watt input,
anechoic environment, band-limlted pink-
noise signal),
Mid Bass: 107 dB
High Frequency: 111 dB
Impedance,
Nominal (mid bass/high frequency):
16
ohms/8 ohms
Minimum (mid bass/high frequency):
11 ohms/6 ohms
Average Efficiency,
Mid Bass:
25%
High Frequency:
25%
Maximum Long-Term Average Mid-Band
Acoustic Output:
75 watts
Beamwidth (angle Included by 6-dB-down
points on polar responses, Indicated one-
third-octave bands of pink noise; see
Figure
2), 600 to 20,000 Hz Horizontal or
Vertical:
60 degrees +/- 25
Directivity Factor
R, (a), 500- to 20,000-Hz
Median (see Figure 3):
18.2
Directivity Index D,, 500- to 20,000-Hz
Median (see Figure 3):
12.6 dB (+3.8 dB, -4.0 dB)
Distortion (120 dB SPL at 1 meter from
mid-bass horn uslng typlcal music
spectrum; see Figure 4),
Second Harmonic,
1,000 Hz: less than 1%
10,000 Hz: less than 1%
Third Harmonic,
1,000 Hz: less than 1%
10,000 Hz: less than 1%
Transducer Complement,
Mid Bass:
DL10X-SH 25.4-cm (10-in.) driver with
Kevlar epoxy composite cone on
rotatable MH660 60 x 60 degree horn
High Frequency:
DH2As2compression driver on HP66
60 x 60 degree horn coaxially mounted
to a mid-bass horn
Polarity (all drivers):
A positive voltage applied to the positively
marked input terminal produces a positive
acoustic pressure at the front of the system
1. Kevlar is a registered trademark of DuPont.
Input Connectlons,
Mid Bass/High Frequency:
Screw terminals (#10) on barrier strip;
each driver can be individually accessed;
high-frequency driver has blocking
capacitor for protection
Construction,
Main Horn Bell:
One-piece black polyester and
fiberglass laminate with composite
reinforcement
Hanging Hardware:
4-point, black , 10-gauge polyester-
powder-coated steel
Dimensions,
Height:
68.6
cm (27.0 in.)
Wldth:
68.6
cm (27.0 in.)
Depth:
71 .1 cm (28.0 in.)
Net Weight:
27.2 kg (60 lb)
Shipping Weight:
33.6 kg (74 lb)
DESCRIPTION
The Electro-Voice MH660C is a two-wayhorn-
loaded speaker system for permanentinstalla-
tion. Because the mouth dimensions of both
the mid-bass and high-frequency horns were
correctly chosen and are large enough with
respect to the wavelengths reproduced, the
MH660C provides unifon directivity control
down to 500Hz. This super directivity control
increases speech intelligibility and musical clar-
ity in difficult acoustic environments. Other
horn systems wlth smaller radlatlng areas
simply cannot provlde the hlgh degree of
directional control associated with the
MH660C.

FIGURE 1 - Typical Axial Frequency Response (anechoic
environment, 1 watt/1 meter into mid-bass section)
, , , , , , ,, , , , , , , , , ,,
, , , , , , , , ,, ,
,
FIGURE 2 - Beamwidth vs. Frequency
FIGURE 3
-
Directivity Factor and Directivity Index vs. Frequency
*
‘W_
a
d
1
I(D g
t,
I0 i
0
FIGURE 4 - Harmonic Distortion (120 dB SPL at one meter from mid-
bass horn using typical music spectrum)
130
FIGURE 6 - Hanging Points
FIGURE 6 - Polar Response
,,,
“.
_’
5OOHZ
HORIZONTAL -
VERTICAL - - -

The MH660C is a 60 x 60 deg. two-way system
with mid-bass and high-frequency horns that
are coaxially mounted. The common acoustic
axes of these horns ensures smooth response
and coverage in the crossover region when the
appropriate signal delay is applied to the high-
frequency driver.
Delivering smooth and extended performance,
the high-frequency sectionoperatesfrom 1,600
to 20,000 Hz and consists of a specially
developed, low-profile
DH2As2 compression
driver coupled to an HP64 60 x 60
constant-
directivity horn. The HP66 horn features inte-
gral fiberglass-and-zinc construction for excep-
tional strength and performance. Beamwidth-
control vanes in the horn throat correct all
coverage anomalies in the
10- to 20-kHz oc-
tave. This horn and driver combination is se-
curely mounted to the mid-bass horn by a
heavy-duty steel bracket.
The mid-bass system is composed of a
DL1 0X-SH 24.5-cm (10-in.) reproducer
mounted on a MH660 60 x 60 deg. mid-bass
horn. The
DL10X-SH reproducer contains a
Kevlar epoxy cone, which is twice as strong as
the conventional paper cone. The mid-bass
section operates between 140 and 1,600 Hz,
and features a proprietary phase plug (U.S.
patent no.
4,718,517) which extends the high-
end output to blend seamlessly into the coaxial
high-frequency section.
If the MH660Cis used in a full-range applica-
tion, additional low-frequency reinforcement,
such as the PI1 15L or a TL-series enclosure
will be required.
APPLICATIONS
The MH660C has been designed specifically
with the permanent installation market in mind.
Sports arenas, performing arts centers, audito-
riums and large gymnasiums are all candidates
for the MH660C. With its superior directivity
control, the
MH660C is a system that can be
used in almost any situation. The
concert-
sound pedigree of the MH660C is evident by
the ease of installation and by the use of profes-
sional-grade components throughout the line.
SUSPENDING MH660C ENCLOSURES
Suspending any object is potentially danger-
ous and should only be attempted by individu-
als who have a thorough knowledge of the
techniques and regulations of rigging objects
overhead. Electro- Voice strongly recommends
that the MH66OC be suspended taking into
account a// current national, federal, state and
local regulations. It is the responsibility of the
installer to ensure the
MH660C is safely in-
stalled in accordance with all such regulations.
If the MH660C is suspended, Electro-Voice
strong/y recommends that the system be in-
spected af
least once a year. If any sign of
weakness or damage is detected, remedial
action should be taken immediate/y.
A manual entitled installing the MH Series is
available from Electro-Voice. It is included with
every MH system and should be followed care-
fully. A general overview is included here to
help the system designer. This overview does
not replacethe installing the
MHSeries manual,
which includes additional information on sus-
pending, configuring and equalizing the MH
series.
1. Kevlar is a registered trademark of Dupont.
The MH660C can be suspended using the two
front brackets and the rear “U” bracket (see
Figure 5). Therear "U” bracket must be screwed
to the rear cover with the bolts provided. Each
of the mounting brackets contains a %-in.-
diameter hole through which a shackle or chain
link could pass. The MH660C can be oriented
in any direction. Electro-Voice strongly recom-
mends that each MH660C be suspended inde-
pendently using at least three of the four sus-
pension points provided.
If the
MH660C is suspended,it is recommended
that the unit be inspected at least once a year.
If any sign of weakness is detected, remedial
action should be taken immediately.
CAUTION: The MH660C speaker systems
should be suspended overhead only In ac-
cordance with the procedures and
Iimita-
tfons specified in the installation manual
Included wlth the systems.
CONNECTIONS
Each frequency section can be individually
connected via#10 screw terminals. All drivers
are connected with the same polarity. A posi-
tive voltage applied to the positively marked
terminal produces a positive acoustic pressure
at the front of the system.
CROSSOVER, EQ AND SIGNAL DELAY
The
MH660C is a two-way system which must
be biamped with a separate active crossover.
24-dB-per-octave crossover slopes are as-
sumed for maximum performance and reliabil-
ity. For optimum performance, EQ and signal
delay are required. (Note: the delays noted
below are for fourth-order
(24-dB-per-octave)
Linkwitz-Riley crossover filter characteristics.)
The mid-bass section should be crossed over
to match the low-frequency section and at
1,600 Hz at the high end. No signal delay or
overall broadband EQ is required. The
high-
frequency section requires a 1,600-Hz cross-
over and the typical constant-directivity-horn
high-frequency boost EQ. A
0.6-msec signal
delay provides the smoothest response in the
crossover region. A low-frequency blocking
capacitor with a
3-dB-down point of 800 Hz is
included.
An Electro-Voice XEQ-3 electronic crossover/
equalizer/time delay unit with EQW plug-in
module provides all of the necessary signal
processing. The
XEQ-3 is a three-way elec-
tronic crossover with adjustable crossover fre-
quencies utilizing Linkwitz-Riley 24-dB-per-oc-
tave filters and signal delay equalization to
achieve zero lobbing error.
FREQUENCY RESPONSE
The MH660C axial frequency response was
measured in Electro-Voice’s large anechoic
chamber at a distance of 3 meters (10 feet) with
a swept sine-wave input (see Figure 1). It has
been normalized for 1 watt/l meter into the
mid-
bass section. Minimal level adjustment and
equalization have been used.
DIRECTIVITY
The directional characteristics of theMH660C
were measured in Electro-Voice’s large
anechoic chamber, with a test signal of one-
third-octave filtered pink noise at the frequen-
cies indicated. A full spherical measurement
system, which is fully compatible with Electro-
Voice’s AcoustaCADD computer-aided de-
sign program, was used. All directional infor-
mation was measured at 6.1 meters (20 feet).
Figure 6 illustrates the nominal horizontal and
vertical polar responses, with the long system
axis vertical. If the mid-bass/high-frequency
module is rotated, then the horizontal and ver-
tical polars should be interchanged.
Figure 2 illustrates the horizontal and vertical
beamwidths. Beamwidth is
the angle at which
the horizontal and vertical polar responses
have decreased in level by 6
dB when com-
pared to the on-axis frequency response.
Figure 3 represents the total directivity of the
MH660C The directivity factor R, (Q) is the
relative value, at a point, when compared to an
ideal spherical response. The directivity index
(D,) is calculated by D, = 10log,,,Re
SERVICE
In the unlikely event the MH660C requires
service, each driver can be replaced or re-
paired. A service data sheet is available from
Electro-Voice.
POWER-HANDLING TEST
Electro-Voice components and systems are
manufactured to exacting standards, ensuring
they will hold up, not only through the most
rigorous of powertests, but also through contin-
ued use in arduous, real-life conditions. Two
main test specifications are used: the AES
Recommended Practice for Specification of
LoudspeakerComponents Used in Professional
Audio and Sound Reinforcement(AES2-1984/
ANSI S4.26-1984) and the EIA Loudspeaker
Power Rating Full Range (ANSI/EIA RS-426-A
1980). Both of these specifications use ran-
dom-noise spectrums which mimic typical mu-
sic and test the thermal and mechanical capa-
bilities of the components. Electro-Voice will
support relevant additional standards as and
when they become available. Extreme, in-house
power tests, whichpush the performance bound-
aries of the components, are also performed
and passed to ensure years of trouble-free
service.
Specifically, the MH660C high-frequency sec-
tion passes AES2-1984/ANSI S4.26-1984 with
the following values:
Z,,, = 6.0 ohms at 7,000 Hz
P = 60 watts
TestVoltage = 19.0 volts rms,
38.0 volts peak (+6 dB)
Selected decade = 1,500-15,000 Hz
The MH660C mid-bass section passes ANSI/
EIA RS-426-A 1980 with the following values:
R,, = 6.9 ohms (1.15 x RJ
P
= 300 watts
Test Voltage = 45.5 volts rms.
91 .0 volts peak (+6 dB)
ARCHITECTS’ AND ENGINEERS’
SPECIFICATIONS
The loudspeaker system shall be a two-way,
active, horn-loaded type. The mid-bass
fre-
quencies shall be reproduced bya singleDL10X-
SH 25.4-cm (10-in.) driver coupled to a MH660
60 x 60 deg. constant-directivity horn. High
frequencies shall be reproduced by a
60-watt
DH2As2 2-inch compression driver coupled to
an HP66 60x60 deg. constant-directivity horn.
The mid-bass andhigh-frequencydevicesshall
be coaxially mounted. The system will repro-
duce frequencies from 140 to 20,000 Hz and
have a nominal coverage pattern of
60 x 60 deg.
The directivity control shall be maintained down
to 500 Hz. The crossover frequency shall be
1,600 Hz. The module shall be capable of
producing average sound levels in excess of

128 dB (1 watt/l meter) in the long term, with
short-term peaks of 134 dB. Provision shall be
made to provide four safe suspension points,
made from 10-gauge steel.
The dimensions shall be 68.6 cm (27.0 in.) tall,
68.6 cm (27.0 in.) wide, and 71.1 cm (28.0 in.)
deep. Weight shall be 33.6 kg (74 lb).
The loudspeaker system shall be the
Electro-Voice MH660C.
UNIFORM LIMITED WARRANTY
Electro-Voice products are guaranteed against
malfunction due to defects in materials or work-
manship 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 pre-
paid. Exclusions and Llmltations: The Lim-
ited Warranty 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 owners manual; (d) malfunction re-
sulting from misuse or abuse of the product; or
(e) malfunction occurring at any time after re-
pairs have been made to the product by anyone
other than Electro-Voice or any of its authorized
service representatives. Obtaining Warranty
Service:
To obtain warranty service, a cus-
tomer must deliver the product, prepaid, to
Electro-Voice or any of its authorized service
representatives togetherwith 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-Voice
at 600 Cecil Street, Buchanan, MI 49107(616/
6956831 or 800/234-6831). lncidental and
Consequential Damages Excluded: Product
repair or replacement and return to the cus-
tomer are the only remedies provided to the
customer. Electro-Voice shall not be liable for
any incidental or consequential damages in-
cluding, 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
orexclusion 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-Voice Speakers and Speaker Sys-
tems are guaranteed against malfunction due
to defects in materials or workmanship for a
period of five (5) years from the date of original
purchase. TheLimited Warranty doesnot apply
to burned voice coils or malfunctions such as
cone and/or coil damage resulting from improp-
erly designed enclosures. Electro-Voice active
electronics associated with the speaker sys-
tems are guaranteed for three (3) years from
the date of original purchase. Additional details
are included in the Uniform Limited Warranty
statement.
Electro-Voice Flying Hardware(including en-
closure-mounted hardware and rigging acces-
sories) is guaranteed against malfunction due
to defects in materials or workmanship for a
period of one (1) year from the date of original
purchase. Additional details are included in the
Uniform Limited Warranty statement.
Electro-Voice Accessories are guaranteed
against malfunction due to defects in materials
or workmanship for a period of one (1) year from
the date of original purchase. Additional details
are included in the Uniform Limited Warranty
statement.
Service and repair address for this product:
Electro-Voice, Inc., 600 Cecil Street, Buchanan,
Michigan 49107 (616/695-6831 or 800/234-
6831).
Specifications subject to change without no-
tice.