Electro-Voice EVI-15, EVI-12, EVI-28 User Manual

EVI-12, EVI-15 and EVI-28

Loudspeaker Systems

Applications Guide

W elcome to the world of V ari Intense® horn
technology from Electro-V oice. This Applications
Guide is not intended as a “very intense” descrip­tion of installation procedures, but more as a partial
description of applications and a discussion with
the designer to help you understand this revolution­ary technology and use the Electro-Voice V ari In­tense® systems to install better-sounding systems
and significantly reduce time and material costs.

In a nutshell, here are the major advantages of

the new EVI systems:

• Rectangular coverage pattern.

Traditional horns deliver an elliptical pattern
to the floor. VI horns deliver a rectangular
pattern, which helps to fill in the corners of
the room. No more costly delay lines or cheap
seats!!

• Even SPL front-to-back.

The unique, patented throat and flare struc­ture of the VI horn delivers a 6-10 dB hotter
signal to the rear of the room, eliminating ear­strain at the back of the seating area and pain­ful ears at the front.

• Greater Intelligibility.

VI horns deliver sound to fill only the
floorplan, providing uniform direct-field SPL
and an order of magnitude less energy into
the reverberant field. This provides an increase
in mid- to high-frequency intelligibility of 6 dB
in most applications.

• One horn replaces two.

With VI technology we’ve eliminated the de­structive interference which occurs between
long- and short-throw horns. We’ve also elimi­nated the cost of a properly designed two-horn
system which must include another power am­plifier channel for good power control and
impedance matching.

• Labor savings in the box.

With structural rigging from the factory, these
systems will fly more conveniently and in less
time than many competitive products. In addi­tion, less time is spent on the aiming and repo­sitioning that is required with traditional long­throw/short-throw horn combinations. This
will save you additional money.

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Installation procedures for any conventional
loudspeaker are fairly well-defined and easy to un­derstand: find an appropriate hanging height and
position that affords a clear path to the listening area
(such as above the center of a stage or above the
lectern in a church), and aim the loudspeaker to­wards the center or just to the rear of center of the
room. With this method you hope to cover the
majority of the room with fairly consistent sound,
but the mid and high frequencies never seem to fill
perfectly . It is frequently aimed a little too far back
and there is a large amount of slap echo, or the
front row is too loud, the back row too soft and the
front and back row corners sound muted due to a
lack of high-frequency energy . Other solutions to
filling the room have been suggested and imple­mented, including a dual-horn format (one long
throw and one short throw). This method works
fairly well, but encounters several problems: the
added expense of another horn/driver combination;
the vastly increased time to physically install and
then tune the level and aiming of two horns; the in­evitable destructive interference patterns through­out the listening area; the expense of another ampli­fier channel to achieve correct impedance match­ing; and the need for a very aesthetically clean in­stallation, with no odd-looking (to the customer)
dangling horns. Another solution is to have a horn
that is variable angle, in order to throw a narrow
pattern to the back of the room. The problem with
this concept is that this doesn’t take into account
the drop in SPL between the near throw (about 25
feet) and the far throw (about 70 feet), so the high
frequencies are about 10 dB down in the back of the
room. T o solve all of these problems, the V ari In­tense® horns were invented, yet another innovation
in the long tradition of Electro-V oice. When properly
aimed, the V ari Intense® horns can provide extremely
even SPL throughout an entire room, filling in the
corners without pushing too much energy at the
back wall, thus avoiding slap echo. The rules of
fixed installation have just changed...

The Electro-Voice EVI-12, EVI-15 and
EVI-28 enclosures are the first in a new generation
of problem-solving systems. The new systems are
designed as a package, with easy mounting, refin­ishing ability , lightweight, compact and unobtrusive
size and shape and the classic musical sound that
Electro-V oice is known for . The new small-format
VI horn maintains consistent directional control
down to 2,000 Hz. In the EVI-12 and EVI-15 the
VI horn is optimally crossed over to an specially

angled woofer. Note: the 12-in. driver in the EVI­12 is at a different angle than the 15-in. driver in the
EVI-15, optimizing the floor pattern with the differ­ing directivities of the two drivers. In the EVI-28,
the VI horn is crossed over to a pair of vertically­arrayed 8-inch woofers with a proprietary technique
that provides delay , amplitude and frequency shad­ing to the two woofers.

The EVI-12, EVI-15 and EVI-28 systems are
installed just like any conventional loudspeaker,
keeping in mind a few simple guidelines. Let me
preface these guidelines with a simple but impor­tant comment: the VI systems are extremely versa­tile and will work in a large variety of applications.
They will work well with tall ceilings, short ceilings,
rectangular rooms, slightly trapezoidal rooms and a
whole host of odd shapes so long as the coverage
area is fairly close to rectangular. The larger
EVI-12 and EVI-15 have been tested in rooms with
12-foot ceilings and performed very well, although
with reduced width of throw . A single EVI-12
was installed in a room 75-foot by 150-foot and an
average R T60 of 4.5 in the mid band and performed
very well with good intelligibility and a minimum of
slap echo. It has been thought in the past that if the
floor pattern does not fit the VI horn exactly , then it
cannot be used at all. This is not the case, and if it
were the case, we could not use standard constant­directivity horns in most applications either. The
larger VI systems have an “optimum” room that is
approximately twice the height in width and three
times the height in length. This is the ideal condi­tion, but the figures and descriptions that follow
should give you a good feel for the wide-range ca­pabilities of the systems.

EVI-12 and EVI-15 Installation:

The nominal floorplan that the system will
cover with equal SPL is approximately two “units”
wide by three “units” long, where the height of the
loudspeaker defines the size of the “unit.” For ex­ample, if the loudspeaker is 18 feet above the floor, it
will typically cover a floorplan of about 36 feet wide
by 54 feet long. In this typical installation (see Fig­ure 1), the back panel of the loudspeaker is mounted
approximately 0.6 units (about 11 feet) back from
the first row and has a nominal angle of the top of
the enclosure parallel to the floor or slightly tilted
back (2 to 3 degrees). For rooms that are much
longer than normal, the VI systems are very easy to
aim and position to fill the entire length. Experi­ments in actual listening rooms have shown that with

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the same mounting height of 18 feet, but with the
front of the enclosure tilted up by approximately
10° (see Figure 2), the total floorplan now encom­passed the same 36 foot width, but at least 64 feet
in length, an additional 10+ feet of extension. Of
course, the front row position has moved back
about 5 feet with the change in angle as shown, but
this is easy to account for when initially positioning
the system (and is exactly what happens if you take
a conventional system and change the angle). For
rooms that are closer to square, tilting the loud­speaker system down by 15° provides a very clean
square pattern. In this case, the offset to the first
row is about 0.25 times the height of the system.
For example, a tall, square room is about 60 feet
wide, and only 65 feet long. Tilting the enclosure
down by 15° at a 30 foot mounting height makes a
60 foot wide by 60 foot long pattern. The offset to
the first row is 0.25 multiplied by the 30 foot height,
or about 7.5 feet forward from the back of the en­closure. Minor adjustments in aiming will make the
SPL fill the room very evenly with no loss in tonality
in the corners and high overall intelligibility .

By contrast, a typical two-way system with a
60° x 40° CD horn in the same mounting location as
Figures 1 and 2 (see Figure 3) produced a floor plan
that sounded tonally fairly consistent with a 20- to
24-foot width and 30-foot depth with an offset of
nine feet to the front row .

On paper, this seems like
adequate performance, but in the room it has very
noticeable

(6 dB or greater) variation in overall level
from side to center, and in some aiming cases over
10 dB of variation from front to back as well as a
pronounced lemon shape. The sides of the first
three to five rows in a church and the last few rows
were noticeably muted and much lower in overall
level. As mentioned before, a two-horn system can
work fairly well, but the physical offsets required
for installation inevitably result in some amount of
destructive interference throughout the room
(see Figure 4). Figure 4 was produced using a
90° x 40° CD horn aimed down by 65° and a
60° x 40° horn aimed down by 30°. The actual
physical offsets were used to simulate the floor
response in direct-field SPL. The displayed figure
agrees very well with the measured response, show­ing a 14-dB variation at 4kHz in a distance of 3 feet
horizontally . T onal changes as a result of interfer­ence pattern change versus frequency were clearly
audible in an acoustically well-behaved room, but
were overall much less audible than for a single sys­tem with a conventional CD horn. Locating drivers

and horns closer together than possible with me­dium-format horns will produce somewhat better
results, but will always result in fairly severe lobing.
Polar measurements in 2° increments show the
lobing very well, but the smoothing required for trans­lation to the EASE 10° resolution database will elimi­nate the vast majority of peaks and dips, resulting
in what appears to be a fairly smooth simulation. In
contrast, the new VI systems have no problems with
interference, and maintain very good tonality even
far to the sides and to the back, outside the “equal­SPL” pattern area. This effect is due to the precise
matching of directivities in the midrange and treble,
giving a consistent (although noticeably quieter) fre­quency response out to nearly 50 feet in width and
65–70 feet in length from the same 18-foot height
and 0° aiming angle. This has the advantage of pro­viding a much more uniform power response into
the reverberant field, ensuring that the inevitable
reflections (minimized by the VI concept) are con­sistent in tonal quality .

EVI-28 Installation:

The EVI-28 makes use of the same high-fre-

quency horn as the EVI-12 and EVI-15, but in­cludes a pair of high-power, high-ef ficiency 8” woof­ers in a very compact package. The system is pro­vided with a 2,000-Hz passive crossover featuring
tweeter protection and a proprietary passive equal­ization circuit that provides frequency-shading, am­plitude-shading and time delay to the two woofers.
An Acoustic Lens Filter on the grille helps to elimi­nate spurious lobes and provides a degree of acous­tic loading. These features heavily modify the polar
response of the two woofers, providing an extremely
uniform polar pattern with a shape that matches the
VI horn’s unique SPL profile. They also smooth
the transition between woofers and the horn to mini­mize horizontal lobes, providing amazingly even
coverage through the crossover point. This extends
the VI characteristic down to 500 Hz in an extremely
compact enclosure.

The high-frequency horn in the EVI-28 is
mounted tilted 15° back relative to the EVI-12
and EVI-15. Along with the polar steering in the
woofer’s crossover , this arranges the dispersion for
long throws relative to the mounting height. The
recommended operational vertical angle is minus
5°from the top surface of the enclosure to minus
45°, defining a maximum used vertical dispersion
of 40°. The standard aiming of the system when it

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