Electro-Voice MM2TC EDS User Manual

SPECIFICATIONS

Frequency Response:

800-5,000
(see Figure

Power Handling,

8

Hours, 6-dB Crest Factor:
25 watts

Impedance:

16 ohms

Sound Pressure Level at
Input Average, Pink Noise Band
from

104

Horizontal Beamwidth:

82O @ 2 kHz (see Figure

Vertical Beamwidth:

82O @ 2 kHz (see Figure 2)

Directivity Factor

10.25 @ 2 kHz

Usable Low-Frequency Limit:

600 Hz

Construction:

Rugged die
transformer housing. Diaphragm is
phenolic impregnated linen
speaker parts are of anodized aluminum
with baked
entrance is provided on the bottom side

Voice

5.1 cm (2.0 in.)

Magnet Weight:

0.93

Magnet Material:

Alnico

Dimensions,

Height:

25.4 cm (10.0 in.)

Width:

16.4 cm (6.4 in.)

Depth:

1

Net Weight:

4.0

Shipping Weight:

4.5

HZ

f

5

dB

3)

(500-5,000

800-5,000

dB

-

Coil Diameter:

kg (2.1 Ib) with plates

1.3

kg

kg

Hz:

R,

(a):

-

cast aluminum case and

-

on acrylic paint. A cable

V

cm (4.4 in.)

(8.8

Ib)

(10.0

Ib)

Hz

pink noise)

1

Meter, 1 Watt

-

Limited

2)

-

base. All metal

DESCRIPTION

The University Sound MM2TC is aconservatively rated 25-watt "submergence-proof'' speaker
designed for wall, ceiling, or bulkhead mounting.

-

The driver employs a diaphragm with a phenolic impregnated linen
with

"W"

shaped Alnico V magnet structure.

Provisions are made in the housing for installation
University Sound model

The voice-coil/diaphragm assembly is protected by a special anit-fungicide treatment and
easily accessible for cleaning by removal of the die-cast reflector on the front of the speaker.

MM2TC

is

The
gases.

self-draining and designed

It

is built

to

5030

(30

W).

penetrate high noise levels in boiler rooms, mines, railroads, etc.

of

a matching transformer such as the

to

withstand fungus, dust, salt spray, live steam, and

base and 2.0-inch voice coil

is

The

bell,

DIRECTIONAL PERFORMANCE

The directional characteristics of the MM2TC
were measured by running a set of polar

_

responses in University’s large anechoic

-

chamber. The test signal was
band-limited pseudo-random pink noise
centered at the
indicated in Figure 1

Additional typical data
Figure

2

beamwidth versus frequency for an MM2TC.

IS0

standard frequencies

is

which indicates 6-dB-down

provided in

%-octave-

FREQUENCY RESPONSE

Figure 3 shows the axial frequency response
of the

MM2TC.

distance of
wave.

It

was measured at a

1

meter, using a swept sine

INSTALLATION

Mounting of the MM2TC is by way of two

13/32’’

holes spaced 5.688” on centers.

A

cable entrance threaded for l/z”-14 I.P.S.
pipe or rigid conduit is provided in the bot
tom side of its cork-neoprene gasketed
transformer housing.

transformer housing shall be die
aluminum and designed

be

ing of diaphragm. Voice-coilldiaphragm
assembly shall be protected by special anti
fungicide treatment.

Transformer housing shall be provided for
installation of line
exceed
in.), by 7.0
diameter holes shall be provided for moun

ting purposes.
Dimensions shall be 25.4 cm (10.0 in.) high,

by 16.4 cm (6.4 in.) wide, by 11.3 cm (4.4
in.) deep. Net weight shall not exceed
(8.8 Ib). The loudspeaker shall be the
University Sound

-

reflector, and weatherproof

removed for easy accessibility and clean

-

5.8

matching transformer not

cm (2.25 in.), by 5.8 cm (2.25

cm (2.75 in.). Two 13/32-inch

MM2TC.

-

cast

so

that reflector can

4.0

WARRANTY

Speakers and Speaker Systems (excluding
active electronics) are guaranteed for five

-

years from date of original purchase against
malfunction due

-

and materials.
unit will be repaired or replaced (at our
option) without charge for materials or labor
if delivered prepaid to University Sound. Unit

to

will be returned prepaid. Warranty does not
extend
coils, or malfunction due

-

tion under other than specified conditions,
including cone
from improperly designed enclosures, nor
does it extend
damages. Some states do not allow the

kg

exclusion or limitation of incidental or
consequential damages,

sion may not apply
than University Sound will void this
guarantee. This warranty gives you specific
legal rights, and you may also have other
rights which vary from state

Service and repair information for this
product: University Sound,
Phone 818l362-9516. FAX [phone]

(Limited)

If

to

finish, appearance items, burned

to

-

University Sound

to

defects in workmanship

such malfunction occurs,

to

andlor coil damage resulting

incidental or consequential

so

to

you. Repair by other

abuse or opera

the above exclu

to

state.

Inc.,

-

-

LOW-FREQUENCY DRIVER PROTECTION

When frequencies below the low-frequency
cutoff for the horn assembly are fed
driver, excessive current may be drawn the
by driver. For protection
and transformer (if driver with built
transformer is used),
with driver, or transformer primary are
recommended.

of

driver, amplifier,

capacitor(s) in series

to

the

-

in

Applications and technical information for
University Sound products:
University Sound, Inc., Technical
Coordinator, Phone
FAX 81

813673292,

Specifications subject

without notice.

8181362-951 6,

to

change

For drivers without transformers:

16-0hm driver, 25

150

V

dc or 150 V non-polarized electrolytic,
or two 150
required value in series, back
70

-

volt lines.

V

V

-

50

mf

dc electrolytics of two times

ARCHITECTS’ AND ENGINEERS’
SPECIFICATIONS

The loudspeaker shall be integral driver and
submergence
impregnated linen
rugged two

The axial frequency response will extend
from 800
exhibit
Sound pressure level will be 104 dB

(1

Wl1 M) with an 800

noise signal applied. Dispersion shall be
at 2 kHz.

I

-

proof speaker with a phenolic

-

base diaphragm and

-

inch voice coil.

to

5,000

Hz

and the horn shall

a

low-frequency cutoff of

to

5,000

to

back, for

600

Hz

Hz.

pink

82O

BASIC GUIDELINES

FOR

THE USE

OF

HORNS AND DRIVERS WITHIN A SOUND SYSTEM.

DESIGNING
The Basic
Many sound systems would have better performance

principles are kept in mind Speakers
should bechosen, aimed and powered
highly absorbtive audience, with no sound aimed at the reflective wall and ceil
ing surfaces Where multiple speakers are required in order
uniformdirect field, their coverage patterns should beonlyslightly overlapped,
so

that each section of the audience is covered by a single speaker To the
extent this ideal is achieved reverberation is minimized and intelligibility is
maximized

The following
two design approaches

What is Reverberation?
Reverberation is the persistence of sound within an enclosure, such asa room,
after the original sound has ceased Reverberation may also be considered
as aseries of multiple echoes
a single continuous sound These echoes decrease in level with successive
reflections, and eventually are completely absorbed by the room

-

Non
An open, outdoor space is considered
as virtually all sound escapes the area without reflection.

Variations in Level Due to Distance for Non
In non
be reduced by half
(this is called the inverse
expected as distance from the speaker is increased from the one
(3 28

Reverberant Environments
Wheresound is reflectedfrom
which the
higher and more constant than predicted by using the inverse
alone

Variations in Level Due
The reverberant field will begin
feet This distance is greatest for the least reverberant rooms and speakers
with narrow beamwidth angles The frequency and beamwidth

provided by the datasheet are still required

of

the direct sound (or direct field) from the loudspeaker(s) which still follows
the inverse square law
intelligibility This is why the sound system designer should seek a uniform
directfield, with
a single speaker with awide beamwidth angle used
reverberant room The direct field will be
the

backof the room that speech will probably be unintelligible

Calculating Variations in Level Due
Each time the power delivered

dropof3dBoccurs Thenomographof

to

be expected as the power varies from the one-watt input typically used in
SPL specifications

Power Handling
The power rating of a speaker must be known

is capable of meeting the sound pressure level requirements of the system
The power rating combined with the sensitivity will enable a system designer
to calculate the maximum sound pressure level attainable at a given distance

FOR

INTELLIGIBILITY AND ADEQUATE SPL

Idea

if

the following basic

with the appropriatecoverage patterns

to

achievea uniform direct field in the

to

achieve a

material explains these concepts in more detail and illustrates

so

closely spaced in time that they merge into

Reverberant Environments

-

reverberant environments, such as outdoors, sound pressure level will

-

foot) measuring distance typically used in SPL specifications.

(6

dB) every time the distance form thespeaker is doubled

-

square law). Figure A shows the dB losses

"

reverberant field" dominates and the sound pressure level is

aslittle reverberantfieldas possible For example, consider

wallsand other surfaces, thereisapoint beyond

to

Distance for Reverberant Environments

It

is the direct signal that contributes

to

be a non-reverberant environment,

-

Reverberant Environments

-

-

square law

todominatetypicallyatdistancesof

to

obtain satisfactory distribution

to

so

far below the reverberant field at

to

to

Changes in Electrical Power

the speaker is reduced by one-half, a level

FigureBshowsthethechangein

cover a long, narrow

to

determine whethera design

10to30

speckations

to

speech

to

meter

be

dB

DISTANCE

FROM

CHANGE

SPEAKE:IH;

-

Powering to Achieve Both Average and Peak SPL
The average power that must be delivered

desired average SPL can be determined from the previously presented
material on speaker sensitivity, level variation with distance and level varia
tion with power. Enough additional power must be available
without distortion the short
Thisdifference between the
when expressed in
or "headroom." The peaks can be large, as noted earlier: at least
the average

The better sound systemsare designed for peaks that are
average, although
voice paging systems The
requiredfor theaveragesound levels The 6
power.

Utilizing Speaker Beamwidth Information for Maximum Intelligibility
Knowing the beamwidth angle

direct field in the listening area After selecting a desired speaker location, the
beamwidth angle needed
over

to

known the correct speaker can be found by using catalog specifications

Using Easy
In some circumstances

than using the basic horizontal and vertical beamwidth angles Environments
which have excessive reverberation or high ambient noise levels make
especially difficult

In recent years a number of computer based techniques have been
developed
systems use personal computers with relatively sophisticated graphics
Simpler systems, such as Electro Voice
Program) utilize clear overlays and require programmable scientific
calculators However, the

to

utilizeeven thesimpler systems are not attractivetosomesound systems
designers Because of this University Sound has developed a special
adaptation of VAMP, called Easy VAMP
aid without the complexity and cost of the VAMP programs

More information
found in the University Sound Guide

M

lmm

::$a

FIGURE

Level Variation Level Variation

With Distance

(1

0

dB).

the walls or ceilings must be determined Once these angles are

-

VAMP

to

help sound system designers Some of the more complex

IN

4

(dB)

M

A

to

the speaker@)

-

term peaks that exist in voice and music program.

peakand averagecapability of a sound system,

dB, is often called "peak-to-average ratio,

6

dB of headroom is sufficient for most general-purpose

1

0-dB peaks require amplifier power ten times that

-

dB peaks require fourtimesthe

of

a loudspeaker can aid in providing a unlorm

to

adequately cover the listeners without spilling

TM

and Floor-Plan Isobars

d

is desirable

to

achieve the desired

hardwareisoftware and training investment required

on

both the Easy VAMP

to

use an approach that is more detailed

SPL

and intelligibility

TM

s

VAMP

TM

which providesa similar design

TM

and floor plan isobars can be

f25

M

3+m

FIGURE B

With Power

to

to

" "

10

dB above the

(Very Accurate Mapping

achieve the

reproduce

crest factor

10

times

-

"

it

Part Number

US 42-02-

Litho

in

0261

U.S.A

531291-923

17