11
INSTALLATION & OPERATION
stage EQs can be used which gives an additional 6 dB of
gain. However, do not boost the gain on the EQ cards unless
it is absolutely necessary.
The 1/3 octave stage channel equalizers in the MOD V
allow the same tuning results obtained in professional room
tuning filter sets used in high-end sound playback applica-
tions. Sound contractors learned, a long time ago, that
boosting frequency bands adjacent to bands that are cut
introduce a phase shift that the ear is very sensitive to.
Although the test instruments show a nice curve, the sound
has a coloration that is not natural. For this reason, we
encourage you to apply the minimum amount of boost and
cut whenever needed. Never over-equalize the system. All
frequencies may be cut and boosted by as much as 7 dB in
each of the 1/3 octave bands without creating the above
problems. The use of bass and treble controls on the equal-
izer has also been avoided to further minimize phase shift.
Each filter section uses a single turn trimpot for adjustment.
The equalizers are factory set for flat response during final
QC test.
Before attempting to equalize be sure the stage speaker con-
nections are properly polarized, the polarity of the compo-
nents in each speaker system is correct, and the speaker
devices are mechanically aligned according to the manufac-
turer’s recommendations. Remember that equalizers are
used to tune the room, NOT to correct poor speaker installa-
tion and alignment.
If LE and RE are being used, turn on the pink noise for
these channels (one at a time) and adjust the output trimpots
for 85 dBC spl. There are no equalizers for the LE and RE
channels.
SUB-BASS LEVELS:
Remove the PREAMP CARD from
its slot and set it aside. Remove the
PINK NOISE CARD from the
MATRIX CARD slot and plug it into
the PREAMP CARD slot. Do not
plug the MATRIX CARD back in yet.
Turn on the LEFT and RIGHT pink
noise switches. Adjust the individual
EQ adjustments on the Sub-Bass Card
for a flat low frequency response from
the subwoofer. Each EQ pot allows a
± 10 dB range. Adjust the OPTICAL
LEVEL trimpot on the Sub-Bass Card
for 90 dBC spl from the subwoofer. In
Music or Mag modes, adjust Music or
Mag pots for the desired sub levels. In
Digital mode, set Dig sub pot per digi-
tal processor instructions.
OPTIONAL GENERATOR FUNCTIONS:
If your MOD V is equipped with the optional stereo and
surround generator modules, then do the following adjust-
ments:
Install the J1 jumper on the Front Stereo Generator Card to
the rear two pins to prevent high frequency attenuation
when in Generator mode. Insure that the Pink Noise
Generator Card is plugged into the preamp slot. Switch on
the pink noise for the Left and Right channels (in phase),
and flip the Digital Time Delay/Surround Generator Card
switch to the TEST position. Turn the surround amp off.
Now adjust the Left, Center and Right generator levels on
the Front Stereo Generator Card to read 82 dBC in the audi-
torium. To do this, switch the power amplifiers off and set
gains one channel at a time, by switching on only the ampli-
fier for that channel being adjusted. Once stage levels are
balanced, switch all power amps on and check to insure that
a sound pressure level of 85 dBC is obtained. Turn off the
stage amps and turn on the surround amp. Adjust the level
pot on the Digital Time Delay/Surround Generator Card for
an auditorium level of 85 dBC. Flip the RUN/TEST switch
back to RUN and turn all amps back on. Remove the Pink
Noise Generator Card.
Plug the MATRIX and PREAMP Cards back into their
appropriate slots.
MUSIC LEVELS:
Set the MUSIC LEVEL control on the front panel to the 3
o’clock position. Select Music mode and turn on the music
source that is feeding the MOD V. Turn the left and right
music level trimpots on the Output/Music Card to obtain a
normal house level. These trimpots are factory set and may
not need adjustment. DO NOT TURN THESE UP TOO
HIGH as music-to-film crosstalk may occur. Adjust the
trimpots so that right and left music are set to the same
level. The music circuit in the MOD V has a simple matrix
which generates four channels of music from any 2-channel
stereo music source.
TIME DELAY:
Locate the 325 DIGITAL TIME
DELAY/SURROUND GENERATOR
Card. The bottom of this card has a
rotary switch. Each position clockwise
on the rotary switch equals 10 mSec
(milliseconds) of delay. Position 0 is
the minimum delay setting which
equals 10 mSec of delay. Position 1
produces a total of 20 mSec of delay,
position 2, 30 mSec, etc. The maxi-
mum amount of delay possible is 160
mSec. Measure the distance in feet
from the ideal seat (which is usually
2/3 of the way back from the stage
speakers, centered side to side) to the
stage speakers. Now measure the dis-
tance from the ideal seat to the nearest sur-
round speaker. Subtract the two measure-
ments. Now add 20 to this number to get the
delay (in milliseconds) required in the audito-
rium. Set the rotary switch to the nearest set-
ting in milliseconds.
DIGITAL LEVEL SETTINGS:
Incoming signals from the Digital input termi-
nals SHOULD be trimmed externally to match
levels from the Stereo-Optical signals. These
adjustments can be made at the output of the
external digital processor or interlock audio
tape machine (see manufacturer’s manual). If
necessary, additional digital level adjustments
can be made on the MOD V EXTERNAL
INPUT/NR SWITCHING CARD, which has
eight trimpot adjustments for cutting or boost-
ing the input level of each individual digital
channel. Normally, this card is set for unity
POSITION
DELAY
0
10
1
20
2
30
3
40
4
50
5
60
6
70
7
80
8
90
9
100
A
110
B
120
C
130
D
140
E
150
F
160