Protection Circuitry - Genelec 1039A Datasheet

1039A Control Room Monitoring System
System
The Genelec 1039A is a very powerful
three-way active monitoring system includ-
ing loudspeaker drivers, speaker enclosure,
multiple power amplifiers and low level active
crossover. Designed for large control room
this system is ideal for music recording stu-
dios, large film and video post-production
facilities and mastering suites, where broad
bandwidth, high SPL's and extended low fre-
quency response are essential. The 1039A is
designed to be flush mounted in the control
room wall.
The unique Directivity Control Waveguide
(DCW TM ) Technology developed by Genelec
provides excellent stereo imaging and fre-
quency balance even in difficult acoustic envi-
ronments. The fast, low distortion amplifiers
are capable of driving a stereo system to peak
output levels in excess of 126 dB SPL at 2 m
with program signals. Versatile crossover con-
trols allow for precise matching of the speaker
system to different acoustic conditions. The
system can be used in both vertical and hori-
zontal orientation by simply rotating the DCW
unit.

Protection circuitry

The 1039A amplifier unit contains electronic
circuitry which serves to protect the drivers
from damage by overload and distortion.
These circuits monitor each amplifier chan-
nel and automatically reduce the signal level
to the driver if an overload condition occurs.
In addition the signal levels to all of the driv-
ers in the loudspeaker are reduced by the
same amount. This preserves the frequency
balance of the loudspeaker. A LED located
on the loudspeaker enclosure indicates the
status of this protection circuitry.
Amplifiers
The bass, midrange and treble amplifiers each
produce 2 x 400 W, 350 W and 120 W respec-
tively of short term power with very low THD
and IM distortion. The electronics have been
carefully designed to ensure the highest sub-
jective sound quality currently possible. The
system incorporates special circuitry for driv-
ers overload protection and amplifiers thermal
protection. A standard 10 m cable is supplied
for the speaker enclosure connection. Longer
lengths are available upon special order.
Drivers
The bass frequencies are reproduced by two
long throw 385 mm (15") bass drivers loaded
with a 320 liters vented box. The -3 dB point
is 29 Hz and the low frequency response
extends down to 25 Hz (-6 dB). The midrange
frequencies are reproduced by a proprietary
130 mm (5") high sensitivity direct radiating
cone driver loaded with the DCW. The high fre-
quency driver is a 25 mm (1") metal dome also
Applications
• Main monitor for large control rooms
• Music recording studios
• Video/Film large post-production
facilities
• TV music production studios
• Mastering Suites
loaded by the DCW with an upper -3 dB point
at 22 kHz. The midrange and high frequency
drivers have field replaceable diaphragms.
Flush mounting
Flush mounting the loudspeaker into a wall
offers important advantages by eliminating
unwanted secondary sound radiation from
the loudspeaker cabinet's edges and nearly
idealizing the radiation space to half space by
eliminating reflections from the wall behind the
loudspeaker. The result is minimization of dif-
fraction effects, linear low frequency response,
increased speaker output, improved transient
response and imaging. The use of the DCW
Technology removes the diffraction effects to
a large extent. Moreover, the 1039A has ver-
satile crossover controls to compensate and
adjust response variations due to different
loudspeaker positioning and room loading.
Crossover filter
The active crossover network consists of
three parallel band pass filters, with cross-
over frequencies at 400 Hz and 3.2 kHz, and
a common balanced input stage. All the filters
are aligned for equal phase and group delay
characteristics and are acoustically comple-
mentary. The filter slopes are 24 dB/octave.
In order to obtain uniform frequency bal-
ance under different acoustic conditions,
special calibrated controls are featured in the