Each Linear Array enclosure is really a modular component of a complete
system. Modules are designed to be used in multiples; thus, a system might
consist of three or four modules as a minimal configuration, and as many as
ten, twelve, or more, in order to obtain the desired power and coverage needed
for larger venues.
The primary benefits of the linear
array are the extremely narrow vertical coverage angle of each module and the
seamless acoustic transition between multiple units. By starting with a narrow
vertical angle, an array can be constructed that produces the exact coverage
required and nothing more. Modules may be assembled in 'flat-pack' formations,
'tight-pack' formations, or combinations of both (as shown in the photo,
opposite right). When tight-packed, each additional module adds 10 degrees of
vertical coverage. Flat-packing the modules adds 5 degrees, plus 6 dB of
additional forward radiated power. In either case it's easy to calculate the
obtainable power levels and the resultant dispersion pattern.
The predictability of the system
gives the designer the means to accurately direct the acoustical energy to the
audience areas, but not beyond. This precise pattern control eliminates
unwanted spillage onto ceilings, floors, walls and other surfaces, which would
otherwise cause destructive reflections.
How Apogee Linear Arrays Achieve
The pattern in the mid and high
frequencies is obtained by a coupling of paired waveguides in each enclosure.
This coupling sums the forwarded radiated power while narrowing the vertical
dispersion. Low frequency vertical pattern control is governed by the total
size of the array, and as modules are added, the pattern control extends to
lower and lower frequencies. As an example, an array of ten ALA-5s will provide
controlled dispersion down to 60 Hz.
Horizontal dispersion in the high
frequency range is controlled by the HF horn flares (horns are available in
either 60 degree or 90 degree formats). Horizontal dispersion in the low
frequencies is achieved by a refinement of the doublet principal. The precise
spacing and angulation of the paired cone drivers produces a well-defined
directional pattern that maximizes forwarded-radiated power while attaining
superb off-axis rejection. Crossover points are carefully chosen to avoid
destructive cancellation in the upper frequencies from the spacing of the cone
ALA speakers bring a new experience to sound reinforcement. Vertical pattern
control is like nothing you've ever experienced; horizontal patterns can be
ordered in either 60 or 90 degree formats for optimum design flexibility, and
off-axis rejection is nothing short of astounding. The result is greater
clarity, articulation and coherence, with phenomenal freedom from feedback. In
many cases an ALA system can eliminate or reduce the need for delay speakers,
and/or critical placement of mics to achieve adequate gain levels. Apogee's ALA
Series will transform your most troublesome shows and installations into
'another job well done'.
Apogee Linear Array Speakers use a simple and effective rigging system (patent
applied for). The enclosures are joined together with various lengths of
connecting bars to achieve the desired angular relationship (see photo right).
The bars are secured in place by aircraft grade retention pins. Configurations
can be altered in seconds, without any special skills or equipment. The rigging
system is equally effective for stacking enclosures on ground supports when
augmented with optional outrigger bars.