Unlike many other
loudspeaker systems of recent years which depart from a conventional box
format, the Allison models One through Four are not clever solutions looking in
vain for problems to be solved. Instaed they were developed as rational answers
to real problems that are important and audible to anyone. Every aspect of
their design is functional, and they are uniquely accurate sound reproducers in
the only environment that really matters: a room for listening to music.
More than a year of
full-time research on the room-loudspeaker interaction has shown that reflected
impedance from the room boundaries increases a conventional loudspeaker's power
output at very low frequencies, but decreases it significantly in the middle-bass
range.
Another unique
aspect of all these systems is the nondirectional dispersion of middle and high
frequencies from drivers with relativel high output level. This is accomplished
witha new type of diaphragm, convex in over-all profile, which is superior to small
dome radiators in dispersion, yet equals the efficiency of ordinary cone
speakers off comparable size.
The ALLISON:ONE
system is our flagship, combining maximum frequency range, power output
capability, and flexibility in placement.
High Fidelity magazine said it is
"the kind of highly accurate sound-reproducer that would attract the
serious listener who is both musically oriented and technically astute enough
to appreciate really fine sound."
An ALLISON:ONE
system is to be used with its back close to a room wall (but not in a corner),
and with the bottom resting on the floor or close to the ceiling. Full design
performance will be maintained if the cabinet is placed within three inches of
these two room boundaries (thus allowing for baseboards and recessed radiators)
and if the center of the cabinet is more than two feet from a side wall.
Because the system is nondirectional in the forward hemisphere there is no
requirement that it be "aimed" at listeners. A stereo pair of these
systems can be used on the same wall, on a pair of adjacent walls, or even on
opposite long walls at the end away from the primary listening area.
In the Allison; Four
system this placement is facilitated by location of the woofer in the top
panel of its bookshelf-size cabinet,
rather than in the normal front-panel location. The distance to one room
boundary (the wall behind the cabinet) is thus held to the absolute minimum,
which maximizes the possible rations of distances. The smoothness of bass
output in practical use of the system is
significantly better than it is for any conventional bookshelf design. Only the
larger Allison systems are better on this respect than the Four.
Specifications
Speaker complement:
Two 10" (254
mm) woofers;
Two 3½" (89 mm) Convex Diaphragm mid-range
units;
Two 1" (25 mm)
Convex Diaphragm tweeters
Crossover
frequencies: 350 and 3,750 Hz
Crossover network:
LC half-section at
both crossover frequencies. Air-core chokes and non-polar computer-grade
capacitors are used. Three-position control switch (accessible from front)
supplied for selection of system acoustic power response, from nominally flat
to concert-hall balance slope.
Impedance: 8 Ω
nominal (7 Ω minimum at any setting
of balance switch)
Efficiency: better than 0,7% when placed at floor-wall
intersection.
Minimum amplifier
power: 30 watts per channel to produce
100 dB sound pressure level in most domestic room environments.
Acoustic power
output capability: 0,5 acoustic watt
minimum , over full frequency range, with 70 watt peak input.
System resonance
frequency: 45 Hz, nominal
Effective system
Q: 1.0. Low-frequency response -3 dB at
35,5 Hz, -6 dB at 29,5 Hz
Enclosure: Stabilized Radiation Loading sealed acoustic
suspension design.
Outside
dimensions: 40" high by 19"
wide by 10¾" front to back
(1002 cm by 483 mm by 273 mm). Internal volume:
2,550 cubic inches (41,8 liters).
Material: High density particle board veneered with
walnut, oiled finish
Weight: 67 lbs (30,4 kg)
Full Waranty for
Five Years