SB-1
Why did Meyer create the SB-1?
The SB-1 is intended to solve one of the most common problems in
large-scale reinforcement: assuring effective high-frequency reproduction
at great distances from the main PA.
Traditional solutions for long-range high-frequency projection have
employed narrow-coverage horns (also called “long throw” horns). But
the sound pressure produced from a horn decreases by 6 dB with each
doubling of distance from the source, and this substantially limits its
useful range. Certain methods for stacking or arraying horns can
increase the system’s throw by effectively moving the acoustical source
farther behind the array, but these techniques break down at
propagation distances greater than about 100 feet.
The SB-1 Sound Beam is the first practical alternative to horns for
large-scale long-throw applications. It produces sound waves whose SPL
decreases by as little as 3 dB per doubling of distance, with flat
response and consistent bandwidth over five octaves — and its pattern
remains consistent for distances up to 500 feet.
What Meyer systems is it designed to work with?
The SB-1 can be used to supplement any large-scale long-throw main PA
system, including those comprised of MSL-3s, MSL-4s, MSL-5s, MSL-6s,
or MSL-10s in any combination.
Meyer
Sound
Q&A
The Meyer Sound SB-1
Parabolic Sound Beam is
a powerful, long-throw
device for projecting
mid- and high-frequency
energy over distances
from 100 to 500 feet.
By producing an
extremely narrow, tightly
controlled beam of sound
energy, the SB-1 enables
very effective long-range
“fill” coverage in largescale sound reinforcement
applications.
The SB-1 comprises an
optimized aspherical
waveguide with 2-inch
throat (4-inch
diaphragm diameter)
compression driver
feeding a large parabolic
reflector, and a 12-inch
cone driver mounted at
the center of the reflector.
Built-in electronics
include dual
complementary
MOSFET class AB/H
amplifiers with 1240
watts total power output,
TruePower™ Limiting
driver protection, and
frequency and phase
response alignment
circuitry. This powerful
combination of
components provides flat
response from 500 Hz to
15 kHz and 110 dB
peak SPL output at
100 meters.
PATENT PENDING
Why use the SB-1 rather than delayed loudspeaker arrays?
Delayed loudspeakers are a common and effective alternative to longthrow horns, but there are some constraints in their application.
As shown in Figure 1a, because the fill speakers are physically separated
from the main array(s), they can only be aligned for seats that lie
directly on their primary axis. For all other seats in their coverage area,
varying differences in path length from the main PA can cause
cancellations that degrade the frequency response. In small-to-moderate
sized installations, the path length differences are generally small
enough that cancellations occur only at very high frequencies. But in
large-scale applications requiring very long throws, cancellations can
develop in the upper midrange, where they can be much more
destructive of fidelity.
By contrast, because of its ability to project over very long distances,
the SB-1 can be placed with the main PA array. When the fill coverage
emanates from the same physical location as the main system, pathlength differences are eliminated, and flat response can be achieved
with far fewer system adjustments.
In enclosed performance arenas, delay speakers also excite the
boundaries of the space from multiple locations, producing uncorrelated
reflections that compromise intelligibility. This problem can be minimized
by carefully controlling the speakers’ coverage patterns and bandlimiting their response, but only at the expense of complicating the
system design and its setup/alignment.
Because the SB-1 maintains consistent 10-degree coverage across its
full range of operation, it can be arrayed and aimed so that virtually all
of its energy falls on — and is substantially absorbed by — the
audience. Destructive reverberation is greatly reduced, the “critical
distance” substantially increases, and clarity is enhanced. Indeed,
listeners have commented that the SB-1 makes a large sound system
seem much closer to them, as though they were listening to studio
monitors in the near field!
How does the SB-1 work?
The SB-1 achieves a very narrow coverage angle and plane-wave
propagation by taking advantage of a large paraboloid reflecting surface.
A parabola is a simple, mathematically-described curve (Figure 2a) that
possesses a unique focal point. A paraboloid surface is formed by
sweeping a parabola around the primary axis that extends through
center of the curve and its focus, so as to describe a three-dimensional
dish. If sound energy radiates from a source at the focus and is directed
onto the paraboloid surface, it is reflected outward in a path parallel to
the curve’s primary axis (Figure 2b). The paraboloid thereby becomes a
highly directional emitter of plane (flat) wavefronts which are capable of
propagating over long distances with minimal loss — much like an
acoustic spotlight.
Despite the efficiency of parabolic reflectors, they have not been used
in sound reinforcement until now because conventional designs are
hampered by a limited frequency range (with substantial lobing in the
lower frequencies) and inconsistent beamwidth (varying with frequency).
The SB-1 addresses and overcomes both of these shortcomings.
Low-frequency lobing is controlled in the SB-1 by a 12-inch cone driver
SB-1
Q&A continued
Meyer
Sound
A
B
x
y
focus
Figure 1A
Figure 2A
mounted at the center of the dish. The cone is driven by special bandlimiting and phase manipulating circuitry that uses phase cancellation to
suppress side lobes in the range of 500 Hz to 1 kHz. This sophisticated
scheme reduces the amplitude of the side lobes by over 50 dB,
substantially extending the usable mid-frequency response.
Constant beamwidth with frequency is achieved by feeding the SB-1
reflector from an optimized aspherical horn that is placed at the focal
point of the dish. Developed using high-resolution measurement in an
anechoic environment, this horn enables the SB-1 to achieve a uniform
10-degree beamwidth at frequencies up to 15 kHz.
Is the SB-1 made for permanent installations only, or is it portable?
The SB-1 physical packaging has been designed to satisfy both fixed and
portable applications. For shipping, the high-frequency pod and its
mounting arms are disassembled and packed in a stowage space that is
accessed through a hatch on the top of the dish. A removable front
cover protects the dish surface and 12-inch cone from damage, and the
enclosure is fitted with handles so that it can be easily maneuvered.
How is it mounted/rigged?
Meyer Sound offers a mounting yoke. Fabricated of heavy-gauge steel
tubing, this rugged rigging fixture suspends the SB-1 dish from one point
on each side, allowing it to be swung through more than 300 degrees
for maximum freedom of vertical aiming. Two hanging points (one on
either side) are provided so that the assembly can be flown.
Alternatively, the yoke allows placing the SB-1 free-standing on a
scaffold or catwalk above the main system.
How is the SB-1 arrayed and aimed?
The SB-1 provides a consistent 10 degrees of coverage over a range of
100 to 500 feet and projects a circular coverage pattern. Best
performance is attained when multiple units are placed with the main PA
array and splayed in an arc at 8 degree angles. This provides a slight
overlap between the patterns of adjacent units for more even coverage.
A surveyor’s transit, placed atop the cabinet for sighting, is handy for
fine adjustments in aiming.
How can I predict coverage from the SB-1 when planning a system
installation?
The SB-1 projects a circular pattern with a consistent 10-degree coverage
angle. As a rule of thumb, the diameter of the projected circle can be
estimated by multiplying the distance from the SB-1 by .175 — so, at
300 feet, for example, the maximum coverage diameter is about 53 feet.
Alternatively, if you are working from a plan view of the venue, you can
use a protractor to lay out 10-degree coverage wedges (remember to
overlap them eight degrees center-to-center for smoother coverage).
What is the maximum distance at which the SB-1 will project over
100 dB SPL?
Under ideal conditions, the SB-1 can deliver over 100 dB SPL at its full
design throw of 500 feet. In practice, however, the SPL at long distances
can be affected by atmospheric conditions — especially at the highest
Figure 2B
SB-1 PHYSICAL DIMENSIONS
frequencies. The best propagation of sound waves occurs when the
air is either very hot and moist, or very cold and dry. In more
moderate conditions, attenuation due to air loss may exceed 3 dB
per doubling of distance from the SB-1.
Interestingly, unlike conventional horn systems, two adjacent SB1s can be aimed into the same coverage area for an increase of 6
dB in SPL — without producing cancellations. This unique property
of the SB-1 can be exploited to compensate for air losses.
Can the SB-1 be modified to work below 500 HZ?
No, the 500 Hz limit is determined by the laws of physics: it is the
lowest frequency (longest wavelength) at which the parabolic
reflector remains effective. To provide the same narrow directivity
at lower frequencies would require a vastly larger dish.
Except in special circumstances, however, there is generally little
need for a highly directional low-frequency device. As reinforcement
professionals know from experience, low frequencies travel farther
(that is, are less quickly absorbed by the air) than high ones, so
long throw capability is less of an issue. If the need arises to steer
very low frequencies so as to avoid them spilling into unwanted
coverage areas, selective phase cancellation techniques are more
economical to implement than very large parabolic dishes.
Is the SB-1 weather-resistant?
While the SB-1 is designed and constructed to withstand touring
and intermittent outdoor use, it is not designed for permanent
outdoor installations. A weather-resistant version is in
development; contact your Meyer Sound representative or the
factory technical support department for details.
Meyer Sound Laboratories, Inc.
2832 San Pablo Avenue
Berkeley, CA 94702
tel: 510.486.1166
fax: 510.486.8356
e-mail: techsupport@meyersound.com
http: www.meyersound.com
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LISTED
3K59
COMMERCIAL
AUDIO SYSTEM
SB1 - 01.049.068.01
Meyer Sound Laboratories
has devoted itself to
designing, manufacturing,
and refining components
that deliver superb sonic
reproduction. Every part of
every component is
designed and built to
exacting specifications
and undergoes rigorous,
comprehensive testing
in the laboratories.
Research remains an
integral, driving force
behind all production.
Meyer strives for sound
quality that is predictable
and neutral over an
extended lifetime and
across an extended range.
Made by Meyer Sound, Berkeley, CA, USA
European Office:
Meyer Sound Germany
GmbH
Carl Zeiss Strasse 13
56751 Polch, Germany
© 1997 Meyer Sound Laboratories, Inc.
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Loop
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Active / Speaker Fault
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10K Ω
Balanced
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LO Limit
HI Limit
SB-1
Earth / Chassis
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220K Ω
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54.0
48.5
18.0
Air Duct
MP-2
Amplifier
REARSIDEFRONT
Pod Storage
Compartment
Yoke
Attachment
Point(s)
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