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(type: SC 8253A )
The model SC8253A Surround Matrix Mixer studio and professional sound-recording system was developed to meet the rigorous requirements of surround sound recording. The transparent user mode coupled with the program-ability of this unit, provides a remarkably flexible solution to demanding technical requirements, while the sound chain embedded ANALOG DEVICES insure great dependability and a brilliant sound quality.
For further information...
Theory:
The dimensional output from a multichannel sound recording requires extra time
and the meticulous attention of the sound engineer. The result incase of a live
concert recording can still be of questionable quality. The problem originates
from the interference resulting from the crosstalk of the multitude of microphones
placed at the original sound recording. This is the reason technologies based on
the arrangements of smaller number of microphones have become popular in the
recording of live concerts.
The SC8253A Surround Matrix Mixer provides an extremely flexible technical
assistance to this popular method, particularly for the triple microphone (two 8 and
an omni characterise) in stereo and 5 point SACD output production.
The device allows the adjustment of the sound sources virtual dimensional
positions, the storing of such positions, and assists in the search for the optimal
settings making a transience free A/B test between each stored settings available
for listening.
Further advantage of the device is the guided analog solution, that provides the
handling freedom of the digital systems while avoiding the pitfall of most popular
digital system's noticeable loss of quality.
Electrical construction:
The unit has 3 + 1 inputs, three for the X ,Y ,W microphones and the fourth can
be used for the reception of a compensation or a bass microphone.
The outputs of the unit are the usual 5 that is 5+1.
The matrix mixer is built twice within the unit (A and B) and this makes it possible
to find the optimal sound as the A/B test can be made without the switch
transience effects.
The dimensional and level positions of each setting happen in 100 steps, the values
are displayed graphically and numerically on the LCD display.
There are 8 memory cells available for the storing of set values. The stored values
can be recalled in the A and B register. The system also provides SUBASE channel
output, which when activated gives the option of sub-compensation with either the
"W" or SUB inputs as a source.
Sub-compensation is the subtraction of the base filter output signal from the signal
of the other channels, and can be activated via the software.
The sub-compensation activation per channel is possible via jumpers within the
unit. The sub frequency band limit can be set via software between (-3dB)80Hz
and 120Hz.
The SUB input when sub is not used, can be used as the compensating input which
makes it possible to subtract the signal from a microphone placed at any location
of the recording stage, thereby beneficially altering the resulting sound scape. The
later function's actual usefulness is dependent on experience and experimentation.
The outputs appear as duplicates for the monitors. Optionally extra monitor card
can be ordered with LEVEL, MUTE and DUMP (fix-20dB) functions.
Physical assembly :
The model SC8253A Surround Matrix Mixer unit holds one independent, 2Units
high (88mm) on standard 19" module. The front panel contains the controls
and the LCD display for the visual output of the values and graphical
representations of the functions. The JOGGER significantly speeds and simplifies
the control of all parameters.
The back panel of the unit houses the 3+1 inputs and the doubled 6 outputs to the
monitors by XRL connector.
The unit further offers the option of sending directional instruction to an exterior
monitor unit, and can be linked to a PC for memory storage. The power connector,
switch and fuse as well as the ?frame lift switch? are also located on the back panel.
Technical Specifications:
inputs differential
input impedance min.10KOhm
balanced phase suppression(1Khz ) min.60dB
amplification settings (jumper) +12dB, +6dB, 0dB, -6dB
outputs symmetric
output impedance max.20. Ohm
minimum load impedance 600. Ohm
nominal output level 0. dBm
headroom min. 18 dB
frequency linearity (betwen 10 Hz - 100 KHz) +,-0.2dB
phase diferent between channels (20 Hz and 20 KHz) max. 0.5°
channel position control 40 dB, accurate to 1 %
output level control of relative channel 40 dB, accurate to 1 %
subase filter (F/ -3 dB) switchable 80 Hz / 120 Hz
harmonic distortion factor (20 Hz - 20 kHz range) max 0.005 %
output noise level under typical operation max -94 dBU
output noise level during MUTE max -100 dBU
MUTE dumping (20 Hz - 20 KHz at 0db amplification ) min. 120 dB
power source: 230 V AC max 30 VA
dimensions : 482 mm (19") x 88 mm (2U) x 350mm
weight 4.5 kp.
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