Orban OPTIMOD-FM 8100A/XT2 User manual

Operating Manual
I
3
I
f •
1
Copyright © 1986 Orban Associates Inc.
MODEL 8100A/XT2
to accompany OPTIMOD-FM Mo el 8100A/1
©fbcin
Orban Associates Inc., 645 Bryant t., an Francisco, CA 94107
Toll Free: [phone], In California, [phone] Telex., 17-1480
95957-00001 8/86
OPTIMOD-FM Six-Ban Limiter
Accessory Chassis

In this section:
Rea this first!
2-2
1. WHAT TO DO
page
CAUTION
I
I
1
Section 2
Installation
2-12
2-13
2-3
2-3
2-3
2-4
2-4
2-5
2-5
2-6
2-6
2-6
2-6
2-7
2-8
2-8
2-9
2-10
2-11
2-12
2. INSTALLATION INSTRUCTIONS
1) Unpack an inspect
2) Reposition jumpers on OPTIMOD-FM Car s.
Fig. 2-1: Jumper Positions, Car #5
Fig. 2-2: Jumper Positions, Car #6
Fig. 2-3: Jumper Positions, Car s #8 an #9
3) Mount an connect XT2.
4) Return Registration Car .
5) Set 8100A + XT2 System Controls.
3. RETROFIT INSTRUCTIONS
1) Open the OPTIMOD-FM ’ s front panel, remove subpanel.
2) Check, a resistors on OPTIMOD-FM Car #PS.
3) Install accessory port in OPTIMOD-FM.
4) Check, replace OPTIMOD-FM Car #5.
Fig. 2-4: Accessory Port #2 Installation
5) Check, rework the OPTIMOD-FM Car #6.
Fig. 2-5: Car #6 Rework
6) Check, rework OPTIMOD-FM Car s #8 an #9.
4. XT2 WITH THE STUDIO CHASSIS ACCESSORY
Fig. 2-6: Stu io Chassis Jumper Positions, Car #5
The installation an servicing instructions in this manual are
for use by qualifie personnel only. To avoi electric shock
o not perform any servicing other than that containe in
the Operating Instructions unless you are qualifie to o so.
Refer all servicing to qualifie service personnel. (p«uL8i3)

2-2
Installation
PRELIMINARY
1. WHAT TO DO
I
READ THIS FIRST!
I
I
I
I
The XT2 itself merely nee s to be mounte in a rack an connecte to the host OPTIMOD-
FM Au io Processor. However, certain jumpers on the host OPTIMOD-FM ’ s circuit boar s
must be repositione to configure the unit for operation with the XT2. In a ition, ol er
OPTIMOD-FM Au io Processors may require simple reworking of some of their circuit
boar s an /or installation of an accessory port
The mo el an serial number of your OPTIMOD-FM Au io Processor are shown on
a rear-panel label.
If your OPTIMOD-FM is Model 8100A/1 with a serial number below 699000, you must
first perform steps 1 an 2 of the RETROFIT INSTRUCTIONS.
If your OPTIMOD-FM is Mo el 8100A (serial number below 638000), you must follow
all of the RETROFIT INSTRUCTIONS before installing the XT2.
If you are installing an 8100A/ST Stu io Chassis, rea XT2 WITH THE STUDIO CHASSIS
ACCESSORY at the en of this section before installing either unit
If your OPTIMOD-FM is Mo el 8100A/1 with a serial number of 699000 or above, you
nee only follow the INSTALLATION INSTRUCTIONS.
In this manual, “ XT2 ” is use to refer the Mo el 8100A/XT2 Six-Ban Limiter. “ OPTIMOD-
FM ” an “ 8100A ” are use interchangeably to refer to the Mo els 8100A or 8100A/1
OPTIMOD-FM® Au io Processor (except where context clearly in icates a specific refer 
ence to one of the two mo els). Together, the OPTIMOD-FM an XT2 form the “ 8100A +
XT2 System ” .

2-3
PRELIMINARY Installation
2. INSTALLATION INSTRUCTIONS
Rea “ WHAT TO DO ” on the prece ing page before continuing.
CAUTION
The XT2 shoul not be installe until the OPTIMOD-FM Au io Processor has been installe
an thoroughly teste on the air.
Allow about an hour for installation.
(Installation must be one with the OPTIMOD-FM off-the-air.)
1) Unpack an inspect.
If you ever re-ship the XT2 (e.g., for servicing), it is best to ship it in the original packing
materials since these have been carefully esigne to protect the unit. Make a mental note
of the metho of packing an save all packing materials.
Packe with the 8100A/XT2 are:
2) Reposition jumpers on O TIMOD-FM Car s #5, #6, #7, and #8.
IMPORTANT: Before continuing, you must follow the RETROFIT INSTRUCTIONS in
this section if the serial number of your OPTIMOD-FM is below 699000 (see WHAT TO
DO on the prece ing page). When the retrofit is complete, return to this step.
a) Open the OPTIMOD-FM ’ s front panel, remove subpanel.
Jumpers may be reset from the front of the chassis while the unit is in the rack, once
the front panel has been opene an the subpanel remove .
Remove the three hex-socket screws at the top of the front panel with a 5/64 ” hex
wrench (provi e with unit). Tilt the hinge front panel ownwar to reveal the
interior. Set the AC POWER switch to OFF. Loosen the four DZUS fasteners on the
subpanel by turning each one-quarter turn counterclockwise with a long 3/16 ” or 1/4 ”
flat-bla e screw river. Taking care not to stress the flat cables beneath it, tilt the top
of the subpanel outwar an to the left to clear the upper chassis lip an the oor
support rail at the right.
1) Two 1.8 -ohm resistors (for step 2 of RETROFIT INSTRUCTIONS)
2) Four 10-32 x 3/4 ” screws (for rack mounting)
3) Final Factory Qualification Test Results for this unit
4) This Operating Manual
Perform a general inspection of the contents of the package to check for obvious amage.
DAMAGE CLAIMS must be ma e by ou against the carrier immediatel upon discover .
Save packing an other evi ence of amage for the carrier ’ s inspector.
To avoi trauma to circuit car components, be sure the OPTIMOD-
FM ’ s AC POWER switch (locate behin the front panel) is set to OFF
before removing or inserting any of the printe circuit car s.

2-4
Installation
PRELIMINARY
6 BAND LIMITER ACCESSORY CHASSIS JUMPER POSITIONS
</■
tn
I
JUMPER A
JUMPER B
JUMPER C
B
I
c JUMPER
I
(CT
Is
3
Z
b) Remove Car #5. Move each of jumpers A, B, an C to the “ 6-BAND LIMITER
ACCESSORY CHASSIS ” position (see Fig. 2-1). Reinstall Car #5.
Fig. 2-1: Jumper Positions, OPTIMOD-FM Car #5
(For Car #5, part number 30741-000-03 only.)
NORMAL
(as shi ed)
NORMAL
(as shi ed)
REVERSE
(for fault diagnosis)
REVERSE
(for fault diagnosis)
JUMPER
IE
(TO
* 3
•> s iH
- _ j
c) Remove Car #6. Move the two links at jumper C to jumper B (see Fig. 2-2). DO
NOT MOVE jumper A. Reinstall Car #6.
BA
tspj
Fig. 2-2: Jumper Positions, OPTIMOD-FM Car #6
(Fbr Car #6, part numbers 30461-000-03 an above only - if your car s look
ifferent, see Appen ix J of your OPTIMOD-FM Operating Manual for jumper locations.)
ih
k

I
2-5
Installation PRELIMINARY
§
MGKhAAU
e>
I
I
3) Mount an connect XT2.
I
■
>
) Remove Car s #8 an #9. On each of Car s #8 an #9, move the link at jumper B
to the “ ACCESSORY CHASSIS ” position (see Fig. 2-3). DO NOT MOVE jumper A
on either car . Reinstall the car s.
e) Reinstall the OPTIMOD-FM ’ s subpanel an close the front panel.
Taking care not to stress the flat cables beneath it, tilt the top of the subpanel
inwar an to the left to clear the upper chassis lip an the oor support rail at
the right The DZUS fasteners turn only 1/4-tum. Don ’ t force them, lest they be
amage in a way that is very time consuming to repair. The subpanel shoul
always be replace since it is an integral part of the chassis RFI protection.
Set the internal AC POWER switch to ON. Raise the front panel an fasten the
three screws that secure it in place.
If the unit was remove from the rack, remount it. Groun the unit an connect
AC power.
a) Mount the XT2 in a rack imme iately below the OPTIMOD-FM.
The XT2*s connecting cable will not reach the connector on the OPTIMOD-FM unless
the XT2 is mounte irectly below the OPTIMOD-FM.
Fig. 2-3: Jumper Positions, OPTIMOD-FM Car s #8 an #9
(For Car s #8/#9, part numbers 30481-000-04 or above only - if your car s look
ifferent, see Appen ix J of your OPTIMOD-FM Operating Manual for jumper locations.)
£
o
Accesses, v
C hassis
C q
H/M
A
w
CD
□□
Fool
:• Mis
• «
? s ■
<2
¥< p 1

2-6
Installation
PRELIMINARY
Both power an signals for the XT2 are supplie through this cable.
4) Complete the Registration Card and return it to Orban.
3. RETROFIT INSTRUCTIONS
b) Plug the flat cable from the XT2 into the OPTIMOD-FM ’ s ACCESSORY PORT #2
an attach the connector with the retaining screws.
The rawings in Appen ix J of your OPTIMOD-FM Operating Manual show component
locations. (If you have the ol er 8100A unit, see Section 6 of the this manual for Car
#5 rawings.) A vice for reworking printe -circuit car s is given in Appen ix F of the
OPTIMOD-FM manual.
IM ORTANT: Skip these instructions if the serial number of your OPTIMOD-FM is
699000 or above.
5) Set 8100A + XT2 System controls.
The OPTIMOD-FM an XT2 work together in a system. The controls on one unit affect
the performance of the other. See Section 3 for recommen e control settings an for
information on customizing your au io processing.
If you are using an 8100A/ST Stu io Chassis, set its controls to the settings recommen e
for the 8100 A in Section 3.
1) Open the O TIMOD-FM ’ s front panel, remove subpanel.
Remove the three hex-socket screws at the top of the front panel with a 5/64 ” hex wrench
(provi e with unit). Tilt the hinge front panel ownwar to reveal the interior. Set the
AC POWER switch to OFF. Loosen the four DZUS fasteners on the subpanel by turning
each one-quarter turn counterclockwise with a long 3/16 ” or 1/4 ” flat-bla e screw river.
Taking care not to stress the flat cables beneath it, tilt the top of the subpanel outwar
an to the left to clear the upper chassis lip an the oor support rail at the right.
If your OPTIMOD-FM is Mo el 8100A/1 with a serial number below
699000 but not below 638000, follow steps 1 an 2 only.
If your OPTIMOD-FM is Mo el 8100 A (serial number below 638000),
follow steps 1 through 6.
Materials: Retrofit Kit RET-27 (available from the factory) contains the parts nee e in
steps 3 through 6. The resistors specifie in step 2 are supplie with the XT2.
These retrofit mo ifications are simple an require only common circuit boar repair skills,
appropriate tools, an a careful, systematic approach. However, to save time an avert
errors, we suggest that you rea through each step in these instructions with boar in han
before beginning work.

2-7
PRELIMINARY
Installation
2) Check, a resistors on OPTIMOD-FM Car #PS.
CAUTION
Allow about 45 minutes for this step.
a) Check the values of resistors R103 an R 104 on the OPTIMOD-FM Car #PS, the
power supply regulator car . (Car #PS is mounte on the insi e of the rear panel.
These large resistors are visible with a flashlight in the rear interior of the unit to the
left of Car #3, once the front panel has been opene an the subpanel remove .)
If the values of R103 an R104 are alrea y 0.62 ohms (blue-re -gol -gol ), or if
“ piggyback ” resistors of 1.8 ohms (brown-gray-silver) have been a e in parallel to
existing 0.91 -ohm resistors, skip to step ).
b) Remove the OPTIMOD-FM from the rack, place it on a bench, an carefully open the
rear panel.
Set the unit on a pa with the rear panel facing you an about 6 ” (15cm) back
from the e ge of the bench. Make certain the power cor is unplugge . Remove
screws which attach the top an bottom covers to the rear panel (eight screws
on each cover). There is no nee to remove the other cover screws. Remove the
nine screws circle in black on the rear panel. Very carefully an slowly pull the
rear panel out about 3/4 ” (2cm), then tilt the top e ge own until the rear panel
is horizontal.
Two 1.8 -ohm (brown-gray-silver-silver or brown-gray-silver-gol ), 1-watt wire 
woun resistors are supplie with the XT2. Ben each lea at right angles (about
1/8 ” from the resistor bo ies), then “ piggyback ” the new resistors onto the ol
on the component si e of the boar . To avoi heat amage, sol er the lea s
together as far away from the resistor bo ies as practical. We suggest you marie
these changes on the power supply schematic. The net value of each resistor is
nbw approximately 0.62 ohms.
) If your OPTIMOD-FM is a Mo el 8100A (with a serial number below 638000), skip
to step 3).
c) Connect a 1.8 -ohm resistor in parallel with R103. Connect another 1.8-ohm resistor
in parallel with R104.
If you have a Mo el 8100A/1 (serial number 638000 or above), close the rear panel
(but not the front panel), remount the unit in the rack, skip the rest of the RETROFIT
INSTRUCTIONS, an follow the INSTALLATION INSTRUCTIONS on page 2-3.
When replacing the rear panel, make sure that no wires are pinche un er the flanges.
Watch for snags in the internal wiring an for any stress on
the ceramic capacitors on the ivi er wall or input filter box.
These capacitors are very fragile an ifficult to replace.

2-8
Installation PRELIMINARY
3) Install accessory port in OPTIMOD-FM (Mo el 8100A, S/N below 638000, onl ).
I
CAUTION
I
Allow about one hour for this step.
a) If a connector is installe in Accessory Port #1, remove the metal plate covering
Accessory Port #2 an iscar the plate an its fasteners.
If no connector is installe , remove the metal plate covering both Accessory Ports.
Save the fasteners, an iscar the plate. Install the metal plate from the Retrofit Kit
over Accessory Port #1, using the fasteners from the iscar e plate.
b) Install the connector in the rear-panel hole marke “ ACCESSORY PORT 2 ” with the
har ware provi e (see Fig. 2-4). Note the orientation of the connector. Dress the
wires as shown, a justing the cable ties as nee e . Connect each wire to the mother
boar as in icate in the table in Fig. 2-4.
Use only mo erate tightening force on the small screws. A #6 (3/16 ” ) hex nut river
is the proper tool, but a 5mm nut river will also work.
The wire lengths have been chosen to provi e enough slack to enable other service
operations on the rear panel to be performe . It woul be unwise to shorten the wires.
The routing shown shoul be followe to avoi possible crosstalk.
Because some of the motherboar traces are close together, inspect your work very
carefully to be sure that you have not create sol er bri ges between traces or pa s.
c) Re-attach the rear panel by reversing the isassembly proce ure.
When replacing the rear panel, make sure that no wires are pinche un er the flanges.
It is safe to tack-sol er to the motherboar with the circuit car s in place except in very
high RF fiel s, in which case all car s shoul be remove . In any case, we recommen
using a sol ering iron with a groun e tip to minimize possibility of circuit amage.
Avoi using excessive amounts of heat or flux at the motherboar , since the connectors
coul be amage by tempering of the contacts through excessive heat or by creeping
flux.
Be sure the OPTIMOD-FM ’ s internal AC POWER switch is
set to OFF before removing or inserting any of the printe
circuit car s.
4) Check, replace OPTIMOD-FM Car #5.
Allow about 5 minutes for this step.
In this an the following two steps, you will be instructe to set car s asi e rather than
reinstalling them. This is to save you from removing them again to set jumpers as irecte
in the INSTALLATION INSTRUCTIONS.

Table 2-1: Wire List For Connector "AP"
CHEDULE WIRE
WiRE
F unction
FROM
TO COLOR,
u 6 NOTH
AP-I
AP-M
l5V PROOF
BUa^iRE
.25 -M
AP-i
AP- 15
.25 in
*i5 V
AP 3
AP- lU
-i5V
APR AP-17
- TOP OF BACKPLANE CRA >5 GND .25 IN
AP - 5
AP-iB .25 ‘ N
D irty gnd
AP- i5
CLEAN <*ND
T5-M
AP- iZ
ri khi F ilter
0LK iN$UuAT£O
AP-fJ
T9-P
•4.5 «N
Rl.lMME F ilter
wh T
J6-F 15 V PROOF i -5 in
AP-IH VlO
AP- i 5
P - (J
B lu
9 IM
N O
AP-lto
7.5 IN
P -a -I V
C»RY
AP-17
0LK 2.5 IN
6 NO LUU
CHA I GND
AP-IB
DiRTy CiND
(J lh
7.5 IN
C lean 6 nd
ap - i3
P -7 0RM
AP-20
•1.5 'N
L LIMITER OUT
R LlMlTCR CUT
• 2 IN
C a RY
AP-21
BACKPLANE P c B
L I k R i FiLTiR
AP-21
JB-M
RED
Jft-P
L2.2 Km F ilter
AP-Z3 ORN
14 IN
A
T ie WRAP
ACCE ORY PORT ’ 1
/
Rt.Af\ PANEL iN lOe vifcw
TOP URI ACL
N>
I
\
I
PO*/tR UPPLY PCB
3
OQ
o
o
o
o
o
o
>
<
“ 0
ZD
m
C
>
n
o
02
o
3
a
4k
NJ
NJ
K
£
a
§
o
o
o
o
o
o
o
o
%
&
p.
g
o
o
o
o
o
o
o
o
o
o
o
o
©I
o
o
o
o
o
o
H o
J o
A O
J
o
o
o
o
o
o
®1
0 s
o
COVHJEJZTOR @
E.E TABLE FOVk NdVK\biG>
(CAMCVA , 0e>-2-5 >>
RO
’ s®
Y O
T o
* O
I o
o
o
o
o

2-10
Installation
PRELIMINARY
a) Remove Car #5 an check the part number etche on the sol er si e.
I
5) Check, rework the OPTIMOD-FM Car #6.
a) Remove Car #6 check the part number etche on the sol er si e.
Allow about one hour for this step.
The rework in this step enables the XT2 to efeat the OPTIMOD-FM ’ s high-frequency
limiters an soft clippers, an it re irects the output of Car #6 to the accessory port
installe in step 3).
) Desol er the non-ban e (ano e) en of glass io e CR603 with a vacuum esol ering
tool. Ben the io e upwar so that the free en is pointing towar S602. Using
the long wire from the kit, connect the free en of CR603 to the center terminal of
S602. Also connect the free en of the 1N4148 io e installe in c) to this terminal.
c) Sol er the ban e (catho e) en of a glass 1N4148 io e to the pa where the center
leg of S602 was attache .
To o this, contact Orban Customer Service at one of the numbers at the front of
this manual to get a Return Authorization number. We will nee to know the serial
number of your OPTIMOD-FM an the six- igit serial number stampe on the car
itself. Only the Car #5 inclu e with the Retrofit Kit (not the one that was alrea y
in your unit) will be accepte for cre it The uplicate Car #5 must be returne to
us within 60 ays of the ate of its shipment to you.
Upon receipt of your uplicate #5 Car , we will mail a refun to the organization
represente as the owner on the Registration Car . If the Registration car is not on
file, other proof of ownership will be require .
If the part number is 30451-000-nn (where -nn is any number) or 30741-000-02
or -01, use #5 Car provi e in the Retrofit Kit (which will have an etche number of
30741-000-03 or higher) instea of the ol car . Do not install the new car yet - set
it asi e, taking care not to confuse it with the ol car .
If the part number is 30741-000-03, the car you have is the correct one for use
with the XT2. Set the car asi e ( o not reinstall it yet) an skip to step 5. You may
return the Car #5 inclu e with the Retrofit Kit to the factory for cre it.
The ol car is not returnable, but can serve as an emergency spare (although you may
hear more processing artifacts with it).
If the part number is 30461-000-05 or above, the car you have is the correct one
for use with the XT2. Set it asi e an skip to step 6).
If the part number is 30461-000-04 or below, continue to b).
b) Remove all the sol er from both si es of the foil pa connecte to the center terminal
of toggle switch S602 with a vacuum esol ering tool. Use fairly strong iagonal
cutters to gently clip the center leg of S602, leaving a stub on the switch long enough
to later sol er two wires (1/8 ” will o). Remove an iscar the portion of the leg
formerly sol ere to the car . Gentle wiggling with chain-nose pliers may help release
it

I
2-11 PRELIMINARY Installation
I
I
Fig. 2-5: Car #6 Rework
I
I
g) Reset the two jumper links (locate on the component si e of the boar , opposite the
switch) so that they each contact only one pin.
This “ storage ” position retains the links so that they can be use to restore the car to
its normal configuration shoul this be necessary in the future.
h) Carefully recheck all work one in step 5), then set the car asi e.
Right out
(to accessory
port #2)
SOLDER SIDE of #6 PCB
P/N 30461-000 Rev 03 or lower
w- — Left Out
\ (to accessory /
\ ort#2) /
abcdefhjklmnprstuvwxyz
Carefully sol er both io es to the terminal. Avoi excess heating an excess sol er
or flux (which coul creep into the switch).
e) Locate an mark pins J an S on the e ge connector. On the component side of the
car , cut both of these traces as close as convenient to the pa s near the car e ge
with a sharp razor knife. Remove about 1/8 ” of each trace to avoi possible shorts.
Note that not all letters are use , an that pin J is therefore the 8th pin from the top
an that pin S is the 15th from the top.
f) Working on the sol er si e of the car , sol er the two short jumpers supplie in the
Retrofit Kit to the pa s in icate in Fig. 2-5.
Because these pa s are so small, there is a risk of shorts. After sol ering, it woul be
wise to remove all flux with a cotton swab moistene with flux remover (Energine®
Fireproof Spot Remover works well) an to examine the area for sol er slivers.

2-12 Installation
PRELIMINARY
6) Check, rework O TIMOD-FM Cards #8 and #9.
I
I
4. XT2 WITH THE STUDIO CHASSIS ACCESSORY
I
I
I
If you are using the 8100A/ST Stu io Chassis, we recommen that the Stu io Chassis an
the OPTIMOD-FM levels be matche to each other before the OPTIMOD-FM is configure
for use with the XT2. See the 8100A/ST Operating Manual for complete instructions.
Leave the covers off the Stu io Chassis following level-matching to facilitate replacing Car
#5. If you have an “ ol ” Car #5 (part number 30741-000-01 or -02 or any part number
beginning 30451), use it uring the alignment between the Stu io Chassis an the OPTIMOD-
FM. If you only have a “ new ” Car #5 (part number 30741-000-03), set its jumpers as shown
in Fig. 2-6 an use it uring the alignment.
Please note that accurate level alignment between the OPTIMOD-FM an the Stu io Chassis
is much less critical when the XT2 is in use, because a stage of gain re uction has been
place between the input of the OPTIMOD-FM an its clippers to protect ±e clippers from
being over riven in the event of gain errors. But if the above suggestions are followe , the
STL will be correctly aligne for the OPTIMOD-FM with Stu io Chassis even if the XT2 is
remove from the system.
The two resistors shoul be positione so that the free lea s cannot acci entally come
in contact with other circuits or with each other. A small piece of tape over the holes
may be helpful.
c) Carefully recheck all work one in step 6), then set the car s asi e.
) Follow the INSTALLATION INSTRUCTIONS on page 2-3.
Allow about 30 minutes for this step.
The rework in this step isconnects the input of each istortion-cancelling low-pass filter
from other circuitry. These inputs will now be riven from the XT2.
a) Remove Car s #8 an #9 an check the part number etche on their sol er si es (both
car s shoul have the same part number).
If the part number is 30481-000-04 or above, the car s you have are the correct
ones for use with the XT2. Set the car s asi e an skip to ).
If the part number is 30481-000-03 or below, continue to b). Rework both car s.
b) Using a vacuum esol ering tool, esol er an lift those lea s of R804 an R805
which are closest to the car ’ s upper e ge. Do not esol er the opposite en s. After
the lea s have been free by ben ing the resistors upwar , clear the holes of sol er
for possible future use.

2-13 PRELIMINARY Installation
J.
IW
o
/n\/n\
JUMPER B
JUMPER C
JUMPER A
I
11U*J
X
z
H
Fig. 2-6: Jumper Positions for Stu io Chassis Alignment, Car #5
(Part number 30741-000-03 or above.)
Note also that when Car #5 is strappe for XT2 operation, it no longer pro uces a “ stan ar
level ” of +3.6 Bm at the Stu io Chassis output, nor oes it cause the OPTIMOD-FM ’ s VU
meter to rea “ 0VU ” in the L or R COMPRessor OUT positions. Instea , its output is re uce
approximately 5 B, causing the “ stan ar level ” test to pro uce -1.4 Bm an the VU meter
to rea “ -5VU ” . This is because Car #5 ’ s limiting threshol is re uce to compensate for
the increase attack time (which increases overshoots on program material) an so maintain
approximately the same program peak levels an STL peak mo ulation.
fl
Gk
* ft
MAlTtg CiAiM CAL.
Qg gs
Oil
_ A'
99 2ir
I Mi B
i ■
p
i h
n
n
o
m
I A I
I.

I
In this section:
page
I
I
I
I
Section 3
Operating Instructions
3-4
3-5
Fig. 3-1: XT2 Controls an Meters
Fig. 3-2: 8100A Controls an Meters
1. RECOMMENDED SETTINGS FOR THE BEST SOUND
Fig. 3-3: Recommen e Control Settings
2. CUSTOMIZING THE SETTINGS
1) Some au io processing concepts.
2) Compression, ensity, an lou ness.
3) Clipping, lou ness, an istortion.
4) High-frequency equalization: presence, brilliance, an lou ness.
5) Bass equalization.
6) More on istortion.
3-6
3-6
3-6
3-7
3-7
3-8
3-8
3-2
3-3

3-2
PRELIMINARY
Operating Instructions
I
I
I
I
Fig. 3-1: XT2 Controls an Meters
I
H-F EQualization controls boost high-frequency
response by up to 6 B.
BRILLIANCE control increases the gain (prior to
limiting) of the 6.2kHz to 15kHz ban . Pro uces
an au ibly attractive effect with increase “ air ” an
“ transparency ” (similar to that of a “ psychoacoustic
exciter ” ).
PRESENCE control increases the gain (prior to lim 
iting) of the 3.7kHz ban . The 3.7kHz ban limiter
will resist such gain increase to prevent intro ucing
excess stri ency into material with excessive pres 
ence energy.
BASS EQualization controls a just the amount of
bass boost. Separate controls for left an right chan 
nels (all other controls affect both channels) pro 
vi e a peaking boost to achieve soli , punchy bass
from most consumer ra ios without exciting the mi 
bass ashboar resonances in cars. Range is O B to
+10 B; center frequency is 65Hz; “ Q ” is 1.4 (ap 
proximately 1 octave). .
CLIPPING control a justs signal level going into
the multiban clippers an therefore etermines the
amount of peak limiting one by clipping. Range
is -4 B to +2 B. This control governs the tra e-off
between lou ness an istortion.
COMPressor switch isables the limiters an clip 
pers when set to PRoof (use for testing).
DENSITY control a justs signal level going into
the six-ban limiter, an therefore controls ensity
of output au io by etermining the amount of gain
re uction in the six-ban limiter. The resulting soun
texture can be open an transparent, soli an ense,
or somewhere in between. Range is 20 B.
6-BAND LIMITER G/R meters show the amount
of gain re uction for each of the six limiter ban s.
Note that the gain re uction in the 6.2kHz ban is
controlle by, an is always i entical to, the gain
re uction in the 3.7kHz ban .

3-3
Operating Instructions
PRELIMINARY
I
I
I
I
I
I
I
I
Fig. 3-2: 8100A Controls an Meters
Use in A justing the 8100 A + XT2 System
RELEASE TIME control a justs how fast the gain
of the “ master ” compressor increases when the pro 
gram material gets soft. Settings towar “ SLOW ”
cause the compressor to act as a slow “ han on the
pot ” . Settings towar “ FAST ” result in increase
program ensity. Changing the RELEASE TIME
control setting has less effect upon au io texture
when the OPTIMOD-FM is operate with the XT2
than when it is operate without the XT2.
BASS COU LING control etermines the range
of ynamic low-frequency (below 200Hz) shelving
equalization. Setting the control towar “ INDEPEN 
DENT ” provi es substantially more ynamic equal 
ization than setting it towar “ WIDEBAND ” .
GATE THRESHOLD control etermines the in 
put level that system consi ers “ noise ” . Au io be 
low this level causes the ual-ban AGC/compressor
to gate, effectively freezing gain to to prevent noise
breathing.
H-F LIMITING control has no effect in the 8100 A
+ XT2 System. Leave this control set to “ 5 ” .
IN UT ATTENUATORS (L and R) a just the sig 
nal level going into the 8100 A + XT2 System an
therefore etermine the range of gain ri ing provi e
by the AGC/compressor.
CLI ING control effect is i entical to the XT2 ’ s
DENSITY control. Leave the 8100A ’ s CLIPPING
control set to “ 0 ” , an use the XT2 ’ s DENSITY con
trol instea .

3-4 Operating Instructions
PRELIMINARY
1. RECOMMENDED SETTINGS FOR THE BEST SOUND
OPEN
TALK
Format: Talk.
SMOOTH
COMPETITIVE
I
I
The 8100A + XT2 System is very flexible, enabling you to fine-tune your air soun for your
target au ience an esire market position.
Figure 3-3 etails four sets of recommen e settings. Each set pro uces a ifferent soun
texture, an each incorporates a ifferent set of tra e-offs between openness, lou ness, bright 
ness, an istortion.
Start with one of these sets of recommen e settings. Spen some time listening critically
to your on-air soun . Listen to a wi e range of the program material typical of your format,
an listen on several types of ra ios (not just on your stu io monitors). Then, if you wish,
customize your soun using the information in “ Customizing the Settings ” , which follows.
Formats: Beautiful Music, Light Pop.
Processing for this soun keeps the levels of announcers an guests con
sistent, pulls low-gra e phone calls out of the mu , an keeps a proper
balance between voice an commercials. Voice is the most ifficult au io
to process, but these settings result in a most favorable tra e-off between
consistency, presence, an istortion.
The soun texture for the station that values a clean, easy-to-listen-to
soun with a tasteful amount of punch, presence, an brightness a e
when appropriate. This is an “ unprocesse ” soun that soun s just right
on music an voice when listene to on small table ra ios, car ra ios,
portables, or home hi-fi systems.
Formats: Album-Oriente Rock, A ult Contemporary, Mo em Country,
Ol ies, Talk.
With these settings, your soun is getting farther away from the balance
an texture of the original recor ing. We think that this is as far as
processing can go without causing noticeable listener fatigue.
Formats: A ult Contemporary, Contemporary Hit Ra io, Ol ies, Mo em
Country, Urban.
This is the major market “ competitive ” soun , emphasizing lou ness
as well as clean au io. The soun from cut to cut an announcer to
announcer is remarkably consistent as the “ texture ” of music is noticeably
altere to a stan ar . Bass has an ever-present punch, there ’ s always a
sense of presence, an highs are in perfect balance to the mi s, no matter
what was on the original recor ing.
The four soun s pro uce by the recommen e settings are:
An “ unprocesse ” soun with a nice sense of ynamic range. With
these settings, the XT2 provi es gentle “ automatic equalization ” to keep
the frequency balance consistent from recor to recor (especially those
recor e in ifferent eras). An for “ backgroun music ” formats, these
settings ensure that your soun oesn ’ t lose its highs an lows.

3-5
Operating Instructions
PRELIMINARY
I
I
Open
Competitive
8100 A Controls:
XT2 Controls:
I
I
Fig. 3-3: Recommen e Control Settings
I
I
SOUND TEXTURE:
Talk Smooth
PILOT
CROSSTALK TEST
COMPRESSOR
LIMITER
0-5dB
0
5
8
8
0
ON
OPERATE
OPERATE
OPERATE
ON
OPERATE
OPERATE
OPERATE
2-3 dB
0
2
2
2
OPERATE
5-10dB
0
5
7
7
2
5-10dB
0
5
6.5
7
4
ON
OPERATE
OPERATE
OPERATE
ON
OPERATE
OPERATE
OPERATE
10~15dB
0
5
4
6
4
4-5dB
+0.5
3
3
4
OPERATE
2-3dB
+1
2
2
3
OPERATE
2-3 dB
+1
3
2.5
4
OPERATE
DENSITY
A just to pro uce no more than the in icate gain re uction on typical program
material, as shown on the XT2 ’ s 700Hz an 1.6kHz meters:
Meters:
CLIPPING
BASS EQ (L & R)
PRESENCE
BRILLIANCE
COMP
INPUT ATTENUATORS
A just to pro uce no more than the in icate gain re uction on typical program
material, as shown on the OPTIMOD-FM ’ s TOTAL MASTER G/R meter:
G!R Meter:
CLIPPING
H-F LIMITING
RELEASE TIME
BASS COUPLING
GATE THRESHOLD

3-6 Operating Instructions
PRELIMINARY
2. CUSTOMIZING THE SETTINGS
I
I
2) Compression, ensity, an lou ness.
1) Some au io processing concepts.
Lou ness is increase by re ucing the peak-to-average ratio of the au io. If peaks are
re uce , the average level can be increase within the mo ulation limits permitte . The
effectiveness with which this can be accomplishe without intro ucing objectionable si e
effects (like clipping istortion) is the single best measure of au io processing effectiveness.
Compression re uces ynamic range in a manner similar to “ ri ing the gain ” ; limiting an
clipping re uce the short-term peak-to-average ratio of the au io.
Compression re uces the ifference in level between the soft an lou soun s to make more
efficient use of permitte peak level limits, resulting in a subjective increase in the lou ness
of soft soun s. It cannot make lou soun s seem lou er.
Six-ban limiting increases au io ensity. Increasing ensity can make lou soun s seem
lou er, but can also result in an unattractive “ busier ” , “ flatter ” , or “ enser ” soun . It is very
important to be aware of the many negative subjective si e effects of excessive ensity when
setting controls which affect the ensity of the processe soun .
Clipping sharp peaks oes not pro uce any au ible si e effects when one mo erately.
Excessive clipping, however, will be perceive as au ible istortion.
The 8100 A + XT2 System is esigne to allow you to make maximum use of compression,
limiting, an clipping, while minimizing the associate processing artifacts. It is important,
however, to remember that there is a fundamental trade-off between loudness, brightness,
densit , and distortion.
The controls in the 8100A + XT2 System give you the flexibility to customize your station
soun . But as with any au io processing system, proper a justment of these controls requires
proper balancing of the tra e-offs between lou ness, ensity, brightness, an au ible istor 
tion. The following provi es the information you nee to a just the 8100A + XT2 System
controls to suit your format, taste, an competitive situation.
The compression which takes place in OPTIMOD-FM makes au io levels more consistent
without significantly altering texture. The XT2 ’ s six-ban limiting au ibly changes the ensity
of the soun an ynamically re-equalizes it as necessary (booming bass is tightene ; weak,
thin bass is brought up; highs are always present an consistent in level).
The various combinations of compression an densit offer great flexibility:
Light compression + light limiting yiel s a wi e sense of ynamics, with a small
amount of automatic re-equalization.
Mo erate compression + light limiting pro uces an open, natural quality with
automatic re-equalization an increase consistency of frequency balance.
Light compression + mo erate limiting gives a more “ ense ” soun .
Mo erate compression + mo erate limiting results in a “ wall of soun ” effect
which may cause listener fatigue.