McIntosh XRT28 User Manual
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McIntosh Acoustic Engineers have refined the line source
Column Loudspeaker System concept to provide superior
sound reproduction in a full range system.
The Loudspeaker System utilizes a patented Column
Design
1
with
multiple four
inch
Midrange
LD/HP
2
Mag-
netic Circuit
Design Driv-
ers and one
inch soft
dome Tweet-
ers. Refer to
figure 1. Since the audio power fed to a column is distrib-
uted among all the drivers, each driver does not have to
work as hard, resulting in greater power handling capabil-
ity and a dramatic reduction in distortion. The Sound
Waves from
the Column
produce a
Cylindrical
Wave Front
with a
stable sym-
metrical
horizontal
sound dis-
persion to minimize undesirable floor and ceiling reflec-
tions that could detract from a stable sound image. In the
illustration the Loudspeaker on the left side produces a Cy-
Introduction
Figure 5
Figure 2
Figure 4
LD/HP
Conventional
1
COLUMN Pat. No. 4,267,405
2
LD/HP Pat. No. 5,151,943
Figure 1
Figure 3
Figure 6
lindrical Wave Front and the Loudspeaker on the right side
produces a conventional Spherical Wave Front. Refer to
figure 2.
The Low Frequency Section of the System consists of
two 10 inch Woofers. They have a large magnet assembly
and long cone excursions with very low levels of harmonic
distortion and frequency response down to 16Hz. Refer to
figure 3. The Woofer also in-
corporates McIntosh’s Pat-
ented LD/HP
2
Magnetic Cir-
cuit Design with shielding to
greatly reduce any external
magnetic field, that could dis-
tort the video image on a TV/
Monitor placed next to the
XRT28 Loudspeaker. Exten-
sive investigating and testing
resulted in a new design con-
cept which utilizes a pair of aluminum shorting sleeves in
the magnetic circuit. Refer to figure 4. The sleeves virtu-
ally eliminate the negative influence of the fluctuating
voice coil field on the permanent magnet field. This results
in lower distortion
due to more linear
magnetic flux in the
voice coil gap. Re-
fer to figure 5. Ad-
ditional benefits are
less volume com-
pression due to im-
proved heat transfer
through the sleeves
and a cooler operat-
ing voice coil. Both measurements, as well as critical lis-
tening, reveal ten times less distortion than previous de-
signs. A good example of this low distortion is incredible
smoothness and clarity in the reproduction of the human
voice.
The Crossover Network used in the XRT28 Loud-
speaker System is designed to ensure an even frequency