Lectrosonics AM8 Assembly instructions

AM8/4
8 Channel Automatic Matrix Mixer
LECTROSONICS, INC.
Rio Rancho, NM
www.lectrosonics.com
OPERATING INSTRUCTIONS
and trouble-shooting guide

2
TABLE OF CONTENTS
INTRODUCTION ................................................................................................... 2
GENERAL TECHNICAL DESCRIPTION ............................................................. 3
INSTALLATION ...................................................................................................... 4
FRONT PANEL DESCRIPTION............................................................................ 6
REAR PANEL DESCRIPTION .............................................................................. 7
OPERATING INSTRUCTIONS ............................................................................. 8
AM8/4 CONTROL PANEL SOFTWARE ............................................................. 10
TROUBLESHOOTING ......................................................................................... 19
FCC PART 15 NOTICE ....................................................................................... 19
SERIAL CABLE WIRING DIAGRAM ................................................................. 20
AMX CABLE WIRING DIAGRAM ....................................................................... 20
SERIAL PORT COMMANDS AVAILABLE ......................................................... 21
SPECIFICATIONS ............................................................................................... 26
SERVICE AND REPAIR ...................................................................................... 27
RETURNING UNITS FOR REPAIR .................................................................... 27
WARRANTY ........................................................................................... Back cover
INTRODUCTION
The AM8/4 is the most advanced automatic matrix mixer available today. Combining 8 automatic
input channels, 2 auxiliary line inputs channels, 4 output channels, and a full crosspoint matrix
system into 1 rack space, the AM8/4 is a compact solution for a wide variety of sound system
applications. 8 nonvolatile preset memory positions mean complete flexibility and reconfigurability.
The 8 automatic inputs utilize Lectrosonics’ patented Proportional Gain plus Autoskew mixing
algorithm* for seamless automatic mixing performance. Input preamp gains include +50dB and
+30dB for both dynamic and electret microphones, and 0dB for line level inputs. Gain trim range on
the inputs is +15dB to -63dB plus off.
The crosspoint matrix allows any input (or combination of inputs) to be routed to any output (or
combination of outputs). Available crosspoints gains include -6dB, 0dB, +3dB, and off. In addition
to the 8 automatic inputs and 2 line inputs, audio from the LecNet Expansion connector can also be
routed to any or all of the 4 outputs.
The AM8/4 features a wealth of programmable features. With 13 programmable inputs and 8
programmable outputs, even the most sophisticated control schemes are straightforward. The
programmable inputs can control input or output level on any grouping of inputs or outputs, memory
preset recall, or matrix crosspoint switching. Programmable outputs can indicate the current state of
a programmable input.
The AM8/4 has an RS-232 port for remote setup or control by a computer or other RS-232 compat-
ible controller. More than one AM8/4 may be coupled together for larger applications.
U.S. Patents 5,402,500 and 5,414,776

3
8 Channel Automatic Matrix Mixer
Rio Rancho, NM – USA
GENERAL TECHNICAL DESCRIPTION
The AM8/4 uses a straightforward analog signal path to provide excellent audio performance. This is coupled with a
sophisticated microcontroller to implement the automatic mixing, matrix control, and programmable input and output
functions. The Adaptive Level Proportional automatic mixing algorithm is used by the AM8/4. This algorithm uses
the signal level pattern at the microphones to derive a pattern of channel gains. For instance, if only one microphone
channel is being spoken into, its level is dominant and that channel gets most of the system gain, while all other
channels are turned down. If more than one microphone is active, they share system gain according to their relative
levels. A “skewing” function gives some advantage to microphones which are active over time, to minimize interrup-
tions from transient noise at other microphones. Since the gain of each channel is apportioned continuously based
on its relative level, no abrupt gain changes are made. This makes the automatic action virtually inaudible.
Figure 1 shows the simplified block diagram of the AM8/4. The microphone preamp is a low-noise discrete design,
which is extensively RF protected. The preamp has three gain settings. The 0dB setting allows an input to accept
line level signals, while the +30dB and +50dB gain settings accommodate both low and high sensitivity microphones.
Switchable 15V Phantom power is provided for each channel.
Following the mic preamp, the audio signal passes through a high quality Voltage Controlled Amplifier (VCA). This
VCA, controlled by a signal from the system D/A converter, is used to implement both static gain control (i.e. mic trim
and remote input level) and gain reduction for the automatic mixing function. A Channel On LED indicates which
inputs are currently active. A sweepable low-cut filter and a shelving high frequency filter provide tone control for
each input.
The 8 automatic inputs and 2 line inputs are routed through an 11 in / 4 out crosspoint matrix. The matrix has
multiple crosspoint gains to accommodate the most complex signal routing needs. Aside from the 10 inputs, the
matrix also includes one other inputs: the LecNet Expansion In rear panel connector.
Signals from the Expansion In and Expansion Out connectors allow easy interface to AM8 mixers. In addition, a Mix
Minus signal is available which allows easy interfacing to teleconferencing hybrids like the TH3.
An RS-232 port is available to allow many of the functions of the AM8/4 to be controlled either by a computer or a
dedicated control system (such as the AMX or Crestron systems).
AM8/4
Block
Diagram
+
-
MIC
PREAMP
TO
A/D CONVERTER
AUTO INPUT (1 OF 8)
MIX BUS 1
MIX BUS 2
MIX BUS 3
MIX BUS 4
AUDIO
LINK IN
+15V
AUDIO
LINK OUT
SERIAL
BUS
MAIN IN
MIX MINUS OUT
AUTO MIX LOG IN
AUTO MIX
LOG OUT
MIX MINUS IN
MAIN OUT
EXPANSION
IN
EXPANSION
OUT
TX
RX
PHANTOM
POWER
VARIABLE LOW CUT
HIGH CUT/BOOST
LINE INPUT (1 OF 2)
INPUT
LEVEL
SPEECH
FILTER
LOG
CONVERTER
AUDIO
VCA
FROM D/A
CONVERTER
VARIABLE LOW CUT
HIGH CUT/BOOST
PREAMP GAIN
0dB (LINE)
+30dB (MIC)
+50dB (MIC)
FROM INPUT
FROM INPUT
FROM INPUT
FROM INPUT
FROM INPUT
FROM INPUT
FROM INPUT
FROM LINE INPUT
FROM LINE INPUT
2
3
4
5
6
7
8
1
2
PROCESSOR
CONTROLLED
SWITCH
ARRAY
LECNET
PORT
(RS-232)
uC
68HC12
BALANCED
LINE OUTPUT 1
BALANCED
LINE OUTPUT 2
BALANCED
LINE OUTPUT 3
BALANCED
LINE OUTPUT 4
15dB
15dB
15dB
15dB
PROCESSOR
CONTROLLED
VARIABLE
RESISTOR
PROCESSOR
CONTROLLED
ATTENUATORS
1
2
3
4
5
6
7
8
9
10
11
12
13
PROGRAMMABLE I/O
PROGRAMMABLE I/O
PROGRAMMABLE I/O
PROGRAMMABLE I/O
PROGRAMMABLE I/O
PROGRAMMABLE I/O
PROGRAMMABLE I/O
PROGRAMMABLE I/O
PROGRAMMABLE INPUT
PROGRAMMABLE INPUT
PROGRAMMABLE INPUT
PROGRAMMABLE INPUT
PROGRAMMABLE INPUT
PROCESSOR
CONTROLLED
VARIABLE
RESISTOR
PROCESSOR
CONTROLLED
VARIABLE
RESISTOR
DIR OUT
MIC IN +
MIC IN -
MIC GND
CHANNEL ON
1 OF 8
LINE IN +
LINE IN -
1 OF 2

4
INSTALLATION
The AM8/4, because it is so highly integrated, is straightforward to install. The following sections explain the installa-
tion and wiring, as well as the software setup of the AM8/4.
AM8/4 Audio Inputs
Each of the 8 automatic AM8/4 inputs is balanced, and
provides 15V phantom power (through 2K ohm feed
resistors to the “+”and “-”input connections). Phantom
power is switchable on a per-channel basis. The drawing
to the right shows two examples of line level interface
with the AM8/4; one, an unbalanced line level source and
the other, a balanced line level source. The 2 line inputs are balanced but without switchable Phantom power.
AM8/4 Audio Outputs
Each of the 4 AM8/4 outputs is balanced. To use an output in the unbalanced mode, take the signal from the “+”
output connection and the output ground. Leave the “-”output floating.
AM8/4 Programmable Inputs
The AM8/4 has 13 programmable inputs which can control a variety of AM8/4 parameters. Each input can respond
to either a contact closure or a continuous voltage. The diagram to the right shows common connections to the
programmable input pins.
Each programmable input is internally pulled up through a 100K resistor to +5V, so no external pull up resistors are
necessary. When using a continuous voltage with one of the programmable inputs, the Function of the program-
mable input must be set to either Analog In Control or Analog Out Control. See the Programmable Input tab in the
AM8/4 Control Panel software for setting all programmable input parameters.
AM8/4 Programmable Outputs
The AM8/4 has 8 programmable outputs which can indicate the current state of a programmable input. Each pro-
grammable output is the electrical equivalent of a contact closure to ground. When a programmable output is
“active”, it conducts current to ground. When the programmable output is “inactive”, no current flows to ground. The
maximum usable voltage for the programmable outputs is 40V, and they will safely conduct up to 100mADC continu-
ous. The diagram on the right shows some typical uses for the programmable outputs.
It is permissible to run LEDs
from the +5VDC pins on the
programmable input connector,
as long as the total LED current
for all LEDS on does not
exceed 100mA. Similarly, 5V
relay coils may also be run
from the +5VDC pins on the
programmable input connector,
as long as the total coil current
for all relays on does not
exceed 50mA. Note that the
diagram shows an external DC
source powering the relay coil.
This will be necessary if coil
voltages above 5V are needed.
Unbalanced Line Level Source
Input +
Input -
Gnd
Input +
Input -
Gnd
Balanced Line Level Source
Pot Connection for Analog Control of Gain
10K Linear Pot
CCW CW
+5V
To Programmable Input Pin - 1k series resistor recommended
Gnd
Contact Closure as Programmable Input
To Programmable Input Pin
Gnd
DC Voltage Source as Programmable Input
To Programmable Input Pin
0VDC (Off) to +5VDC (On)
Gnd
1k Ohm
LED is on when the programmable output is active
+5VDC (from Pin 14)
380
Ohms
Programmable Output Pin
380
Ohm
s
LED is off when programmable output is active
+5VDC (from Pin 14)
Programmable Output Pin
GND (from Pin 15)
Relay is on when programmable output is active
Programmable Output Pin
GND (from Pin 15)
Relay Coil
Coil current < 100mA 1N4001
or equiv. External DC Voltage
Source (<40VDC)

5
8 Channel Automatic Matrix Mixer
Rio Rancho, NM –USA
Audio Expansion In/Out
When multiple AM8/4s are used in an application, their Audio Link ports must be interconnected using the Audio Link
In/Out connectors on the rear panel of the AM8/4. The Audio Link In/Out connector is just to the right of the Program-
mable In/Out connector on the rear panel. An 8 pin mini-DIN cable is supplied with each AM8/4 for this purpose.
When installing the AM8/4s in a rack, the Master AM8/4 should be mounted in the top of the rack, with Slave AM8/4s
mounted below the Master AM8/4. The 8 pin mini-DIN cable then connects the Audio Link In connector of the Master
AM8/4 to the Audio Link Out connector of the first Slave AM8/4. If there is more than one Slave AM8/4, the Audio
Link In connector of the first Slave AM8/4 is connected to the Audio Link Out connector of the second Slave AM8/4,
and so on for as many Slave AM8/4s as exist in the system.
M
A
S
T
E
R
S
L
A
V
E
EXPANSION
I
N
O
U
T
AUDIO LINK
I
N
O
U
T
OUT IN
EXPANSION
E
X
P
A
N
L
O
C
A
L
TH3 Rear Panel
Switch in "EXPAN" position
AM8/4 Rear Panel
Switch in
"
MASTER"
position
Connecting multiple AM8/4s together Connecting the AM8/4 to the TH3
AM8 Rear Panel
Switch in "SLAVE" position
OUT IN
EXPANSION
M
A
S
T
E
R
S
L
A
V
E
Switch in
"MASTER"
position
M
A
S
T
E
R
S
L
A
V
E
EXPANSION
I
N
O
U
T
AUDIO LINK
I
N
O
U
T
AM8/4 Rear Panel
Connecting the AM8/4 to the AM8
OUT IN
EXPANSION
E
X
P
A
N
L
O
C
A
L
TH3 Rear Panel
Switch in "EXPAN"
position
AM8/4 Rear Panel
Switch in
"MASTER"
position
M
A
S
T
E
R
S
L
A
V
E
EXPANSION
I
N
O
U
T
AUDIO LINK
I
N
O
U
T
Video
Codec
OUTIN
CODEC
Connecting the AM8/4 to the TH3 and a video codec
Switch in
"
MASTER"
position
Switch in
"SLAVE"
position
To additional AM8/4s
M
A
S
T
E
R
S
L
A
V
E
EXPANSION
I
N
O
U
T
AUDIO LINK
I
N
O
U
T
M
A
S
T
E
R
S
L
A
V
E
EXPANSION
I
N
O
U
T
AUDIO LINK
I
N
O
U
T
Switch in
"SLAVE"
position
M
A
S
T
E
R
S
L
A
V
E
EXPANSION
I
N
O
U
T
AUDIO LINK
I
N
O
U
T

6
When other LecNet devices are used in conjunction with the AM8/4s, the LecNet Expansion ports of these devices
must also be interconnected. Refer to the diagrams above for proper interconnections. The LecNet Expansion In
and Out pinouts are shown below.
Pin Expansion In Function Expansion Out Function
1 Main In Main Out
2 Mix Minus Out Mix Minus In
3 NOM In NOM Out
4 NOM Total NOM Total
5 RS-232 RX RS-232 RX
6 RS-232 TX RS-232 TX
7 Ground Ground
8N/C N/C
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
LecNet
Expansion
Out
LecNet
Expansion
In
LecNet Expansion In/Out
FRONT PANEL DESCRIPTION
AM8/4 Front Panel
CHANNEL ACTIVITY SECTION
CHANNEL ACTIVITY LEDS - Indicates channel activity. The LEDs light when the attenuation applied by the auto-
matic mixing algorithm is less than or equal to 6dB.
RESET DEFAULTS –When pressed during power-up, resets the preset memories to their factory defaults. Note that
this will overwrite any user information which may have been stored in the preset memories. There are two reset
modes. If the Reset Defaults button is held in during the first blink of the Power LED after turn-on and then released,
only the preset memories will be set to factory defaults. If the button is held through two blinks of the Power LED, the
LecNet address will be reset to 145 and the preset memories will be set to factory defaults.
LECTROSONICS, INC.
AUTOMATIC MATRIX MIXER
CHANNEL ACTIVITY
12345678
POWER
RESET
DEFAULTS
Pin Link In Function Link Out Function
1 In 1 Out 1
2 In 2 Out 2
3 In 3 Out 3
4 In 4 Out 4
5Gnd Gnd
6N/C N/C
7N/C N/C
8N/C N/C
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
Audi
o
Link
Out
Audi
o
Link
In
Audio Link In/Out

7
8 Channel Automatic Matrix Mixer
Rio Rancho, NM –USA
REAR PANEL DESCRIPTION
AM8/4 Rear Panel
MIC/LINE INPUTS 1-8 - Accepts balanced or unbalanced signal. Fully balanced differential input, RF filtered.
DIR OUT - Provides a line level signal from each individual channel. The direct output is a post-VCA signal. Any attenua-
tion from the auto mixing process, compressor/leveler system or remote attenuation will be reflected in the direct out signal.
This provides versatility for different mixing applications such as distributed overhead speaker systems. This 100 Ohm
output provides a +20dBu max signal into a high impedance load.
PWR
IN
(PS60)
16.5 VAC
20VA
M
A
S
T
E
R
S
L
A
V
E
EXPANSION
I
N
O
U
T
LecNet
(RS232)
1 - Prog I/O 1
2 - Prog I/O 2
3 - Prog I/O 3
4 - Prog I/O 4
5 - Prog I/O 5
6 - Prog I/O 6
7 - Prog I/O 7
8 - Prog I/O 8
9 - Prog IN 9
10 - Prog IN 10
11 - Prog IN 11
12 - Prog IN 12
13 - Prog IN 13
14 - +5V
15 - GND
PROGRAMMABLE IN / OUT
AUDIO LINK
I
N
O
U
T
+
–– + + –– +
4321
+
–– +
21
OFF ON
PHANTOM PWR
12345678
DIR
OUT
+
–
CH8 IN
0dB GAIN
(LINE) +30dB GAIN (ELECTRET) +50dB GAIN
(DYNAMIC)
+
–
CH7 IN
DIR
OUT
DIR
OUT
+
–
CH6 IN
+
–
CH5 IN
DIR
OUT
DIR
OUT
+
–
CH4 IN
+
–
CH3 IN
DIR
OUT
DIR
OUT
+
–
CH2 IN
+
–
CH1 IN
DIR
OUT
CH1 - CH8
OUTPUTS LINE IN
Note: The DIR OUT shares a ground with the OUTPUTS.
--Don’t use the CHANNEL IN grounds for the DIR OUT!--
When connecting to other equipment, the ground connection of the OUTPUTS will also be adequate for
all the direct outputs. A separate ground connection is not needed for each direct out.
GAIN SELECTION SWITCHES 1-8 - Allows input channel gain to be set. 0dB gain, for line level sources, is set when both
switches of the pair are in the up position. 30dB gain, typically for high output (electret) microphones, is set when the left
switch is in the up position and the right switch is in the down position. 50dB gain, used for low output (dynamic) micro-
phones, is set when both switches are in the down position.
LINE INPUTS 1-2 –Accepts line level balanced or unbalanced axillary inputs. The line inputs do not participate in the
automatic mixing algorithm.
LINE OUTPUTS 1-4 - Provide balanced system outputs. The Line Outputs may also be used in an unbalanced mode by
connecting the “+”terminal of the Line Output to the signal lead of the unbalanced device, and the ground terminal of the
Line Output to the ground of the unbalanced device. Do not connect the “-”terminal of the Line Output.
AUDIO LINK IN/OUT - Provides a means to link the four output buses of multiple AM8/4s. All inputs from all linked AM8/4s
will be available at the outputs of the master AM8/4.
PROGRAMMABLE INPUTS/OUTPUTS - Allows remote control of a number of AM8/4 functions. Pins 1-8 on the 15 pin D-
Sub connector may be programmed to be either programmable inputs or programmable outputs. Pins 9-13 are program-
mable inputs only.
Each of the 13 programmable inputs can utilize either continuous DC voltages (0VDC-5VDC) or contact closures, depend-
ing on the particular function chosen. For continuous voltages, either 10K ohm linear pot or an adjustable DC control
voltage may be used. The volume control action is internally audio scaled in software. This gives an “audio-taper”charac-
teristic to a linear pot. When using a DC control voltage, the control constant is .167V/dB (or 6dB/V) from 0V to 5V. At 0V,
the channel is turned completely off. The control voltage should not exceed 5V.
Programmable outputs allow indication of programmable input states. Each of the 8 programmable inputs is the electronic
equivalent of a contact closure. The logic output will sink up to 100mA at voltages up to 40VDC, however, the total current
draw of all logic outputs should not exceed 50mA if the internal +5V supply is used.
AUDIO EXPANSION IN/OUT - Allows multiple AM8/4s to be linked together when more than 8 inputs are needed. In
multiple AM8/4 setups, one AM8/4 is set to be the Master, and all others are set to be Slaves. The Audio Expansion In of
the Master AM8/4 is connected to the Audio Expansion Out of the first Slave AM8/4, using the supplied LecNet Expansion
cable. The Audio Expansion In of the first Slave AM8/4 is connected to the Audio Expansion Out of the next Slave AM8/4,
and so on.
RS-232 SERIAL PORT - Provides access to and control of some of the operational features of the AM8/4. The port is
compatible with the serial port of a PC, or other controllers with RS-232 type serial ports. For hardware interconnection
and software details, see Appendix 1, “Serial Port Hardware and Software”.
EXPANSION IN/OUT - Allows other LecNet devices to be connected to the AM8/4. Also used when multiple AM8/4s are
connected together to bus the RS-232 serial connection between AM8/4s.
MASTER/SLAVE SWITCH - Sets the AM8/4 for use as a Master device or a Slave device. AM8/4s used singly should be
set for Master mode operation.
PWR IN - Connects to the PS60 power supply to provide power for the AM8/4.
PHANTOM POWER SWITCHES - Allow +15V phantom power to be applied or not on a per-channel basis.

8
OPERATING INSTRUCTIONS
Since most of the parameters used to set up the AM8/4 are adjusted using the AM8/4 Software Control Panel, the
operating instructions include instructions for the use of the software. It’s recommended that you have the software
running, either live or in the demo mode, as you read through this section.
Power Up
When the AM8/4 is powered on, it automatically loads the active setup from Preset 1. Therefore, you should always
store the desired power-up setting for the AM8/4 in Preset 1.
Master/Slave Switch
The Master/Slave switch should be set to the Master position if only one AM8/4 is being used. When multiple AM8/
4s are used in a system, only one is set to Master and the rest are set to Slave. See also the wiring descriptions of
the Audio Expansion In/Out and Expansion In/Out connectors in the Installation section.
Input Preamp Gain
Input preamp gain is set using the dip switches just to the left of each 5 pin input connector. Dip switch settings for
0dB, +30dB, and +50dB input gain are shown on the rear panel of the AM8/4. Generally, the +50dB position is used
for all dynamic microphones and electret microphones where the working distance from the microphone will be
greater than about 18 inches. The +30dB position is useful for electret microphones with working distances less than
18 inches and most wireless microphones. The 0dB setting is for line level sources. Remember to switch phantom
power on for electret microphones and off for dynamic mics or line level sources.
Using the AM8/4 PC Hosted Control Panel
The AM8/4 control panel may be used in one of two ways. When launched from the LecNet Master Pro application,
you can control all the parameters of the AM8/4 in real time. Needless to say, your PC must be connected to the
AM8/4 using the supplied LecNet serial cable in order for this to happen. Alternatively, you can launch the AM8/4
control panel directly and it will automatically come up in the demo mode. The demo mode is useful for doing system
setup (and saving the setups to a disk file) without the need to be connected to an AM8/4.
System setup follows the order of the tabs on the control panel. Start at the left tab and work your way to the right.
Please refer to the AM8/4 Control Panel Software section of this manual for a complete description of each control
panel tab.
The diagram below represents the signal flow of one input to one output through one matrix crosspoint. Illustrated
are all the gain control points in the signal path.
To adjust this parameter:Use this control:
Mic Preamp Gain Rear panel dip switches
Input Gain Input gain tab on AM8/4 control panel software
Rear Panel (Input) Gain Programmable inputs on AM8/4 rear panel
Output Gain Output gain tab on AM8/4 control panel software
Rear Panel (Output) Gain Programmable inputs on AM8/4 rear panel
Each input channel has two gain control points, in addition to the rear panel preamp gain switches. The input control
point labeled “Input Trim”is adjusted using the Input Gain tab on the AM8/4 control panel. This control is used to
adjust the sensitivity of each microphone or line level input to the desired gain. The gain adjustment range is +15dB
to -63dB plus off. You may want to increase the mic preamp gain if you find that your input gain settings are routinely
above +10dB.
Input Channel (1 of 16) Matrix Crosspoint
(1 of 216)
Output Channel (1 of 12)
Mic Preamp
+50dB, +30dB, 0dB
Front Panel
+9dB, to -9dB, Off
Input Gain
+15dB to -63dB, Off
Rear Panel
0dB to -30dB, Off
Mic/Line In Tone Controls
Front Panel
+9dB to -9dB, Off
Output Gain
+10dB to -68dB, Off
Rear Panel
0dB to -30dB, Off
To Balanced
Output Drive
r
+6dB
+3dB
0dB
-5dB
-10dB
-15dB

9
8 Channel Automatic Matrix Mixer
Rio Rancho, NM –USA
The input control point labeled “Rear Panel”represents the gain adjustments which can be made from the rear panel
programmable inputs. The rear panel gain control is attenuation only, starting at a maximum gain of 0dB. The rear
panel input gain controls may be limited in their adjustment range using the Remote Input/Output Level Limits tab on
the AM8/4 control panel. In addition, you may set a rear panel preset gain value that will be applied to any outputs
which are being controlled by a programmable input. The preset gain is applied at power up. Note that if there are
no limits applied to the rear panel gain range, the input channel may be turned completely off. The current gain value
of the rear panel controls is displayed on the Remote Input/Output Level Limits tab.
The output gain structure is identical to the input gain structure. The Output Gain range adjustment is +15dB to -
63dB plus off. The output gain is adjusted using the Output Gain tab. Rear panel output gain control ranges may be
set in a similar fashion to the input control ranges in the Remote Input/Output Level Limits tab.
Matrix crosspoint gain can be set using the Matrix tab. Input-to-output gains are set based on the requirements of
the application. For example, you can set up a “mix-minus”sound reinforcement system when you are using multiple
microphones and overhead distributed speakers. Each speaker (or small group of speakers) would be fed from its
own mix of microphones. A given speaker’s mix would consist of all microphones not physically close to the speaker,
while excluding those microphones which are close to the speaker. The possibility of feedback is greatly reduced
when this approach is repeated with all system speakers. A multichannel amplifier (like the Lectrosonics PA8) may
be used to power each speaker individually.
Programmable inputs and outputs may be set up using the Programmable Input/Output tab. Below is a short list of
typical applications for each of the programmable input functions available:
Analog In Control: Used to control the input gain of one or more inputs with a potentiometer or DC
voltage source. Additionally, a toggle switch can be used as a mute switch by shorting the program-
mable input to ground for mute.
Increase In 1dB, Decrease In 1dB: Used to control the input gain of one or more inputs with
momentary switch closures. Each switch closure will increase or decrease the gain of the associ-
ated input(s) by 1dB. If the switch is pushed and held, it will continue to increment or decrement until
the switch is released or the gain reaches its high or low limit.
Analog Out Control: Used to control the output gain of one or more outputs with a potentiometer or
DC voltage source. Additionally, a toggle switch can be used as a mute switch by shorting the
programmable input to ground for mute.
Increase Out 1dB, Decrease Out 1dB: Used to control the output gain of one or more inputs with
momentary switch closures. Each switch closure will increase or decrease the gain of the associ-
ated input(s) by 1dB. If the switch is pushed and held, it will continue to increment or decrement until
the switch is released or the gain reaches its high or low limit.
Memory Preset: Used to recall one of the 15 AM8/4 preset memories with a momentary switch
closure. Remember to save the same memory preset associations in all the AM8/4 memory preset
positions you’ll be using. You can also assign a programmable output to reflect the programmable
input state of the programmable inputs you’re using for memory preset recall to drive LEDs for visual
feedback of the current memory preset.
Toggle Crosspoint Gain: Used to temporarily apply the signal from any one of the 16 inputs to any
combination of outputs using a momentary switch closure to toggle the state of the affected
crosspoints. Useful for zone paging applications, etc.
Mute In: Used to mute one or more inputs with a switch closure. Subsequent contact closures
toggle between mute and unmute. You can also assign a programmable output to reflect the pro-
grammable input state of the programmable inputs you’re using for input muting to drive LEDs for
visual feedback of the mute/unmute state of the inputs.
Mute Out: Used to mute one or more outputs with a switch closure. Subsequent contact closures
toggle between mute and unmute. You can also assign a programmable output to reflect the pro-
grammable input state of the programmable inputs you’re using for output muting to drive LEDs for
visual feedback of the mute/unmute state of the outputs.

10
Programmable Output: Used to provide user feedback for certain programmable input functions. A
programmable i/o whose function is Programmable Output will be active (i.e. conducting to ground) or
inactive (i.e. open) as follows depending on the function of the programmable input with which it is
associated:
Increase In 1dB: Active - Contact closure on prog input
Inactive - No contact closure on prog input
Decrease In 1dB: Active - Contact closure on prog input
Inactive - No contact closure on prog input
Increase Out 1dB: Active - Contact closure on prog input
Inactive - No contact closure on prog input
Decrease Out 1dB: Active - Contact closure on prog input
Inactive - No contact closure on prog input
Preset Recall: Active - Associated memory is active
Inactive - Associated memory is not active
Toggle Crosspoint Gain: Active - Input-to-output(s) connection made
Inactive - Input - output(s) connection not made
Mute In: Active - Associated input(s) not muted
Inactive - Associated input(s) muted
Mute Out: Active - Associated output(s) not muted
Inactive - Associated output(s) muted
Not Used: Unassigns a programmable input from any system function.
When all tabs are set appropriately for the application, the system is ready to use.
AM8/4 CONTROL PANEL SOFTWARE
The following section is a description of the File menu and each of the tabs in the AM8/4 Control Panel application.
File Menu Options
Copy Preset(s) to AM8/4 from Disk File... - Allows any preset stored to a disk file (.amd file extension) to be loaded to
the corresponding AM8/4 memory preset. The Preset 1 through Preset 8 selections copy a single preset, while the All
Presets selection copies all 8 presets to the AM8/4. After a preset is loaded to the AM8/4, it will be transferred to the
active AM8/4 setup. If all 8 presets are loaded, preset 1 will be made the active preset. This option is helpful in restor-
ing AM8/4 settings if they have been accidentally corrupted. Note that this option will overwrite any data stored in the
AM8/4’s preset memory with the new preset data from disk.
Save Preset(s) from AM8/4 to Disk File... - Allows any preset currently stored in the AM8/4’s preset memory to be
saved to a disk file. The Preset 1 through Preset 8 selections copy a single preset, while the All Presets selection
copies all 8 AM8/4 presets to the selected disk file. This option is helpful in archiving the final settings for the AM8/4 in
a particular installation.
Load Active Setup from Disk File... - Allows the active AM8/4 setup to be loaded from a disk file. Loading the active
AM8/4 setup from a disk file will not overwrite any AM8/4 preset memory data. This option is helpful when a basic
AM8/4 setup has been generated off-site and needs to be “tweaked”on-site.
Save Active Setup to Disk File... - Allows the active AM8/4 setup to be stored to a disk file. You select which preset
position in the disk file to which to store the active AM8/4 setup. This option has no effect on the AM8/4 preset memo-
ries.
Select Active Setup from AM8/4 Preset... - Allows any of the AM8/4 preset memories to be recalled and made to be
the active AM8/4 setup. This option does not affect any of the preset memory data.
Save Active Setup to AM8/4 Preset... - Allows the active AM8/4 setup to be stored in one of the 8 preset memories in
the AM8/4. Note that this option will overwrite any preset memory data stored in the selected preset memory position.

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8 Channel Automatic Matrix Mixer
Rio Rancho, NM –USA
Enter Input/Output Names... - Allows names to be assigned to the 10 inputs and the 4 outputs of the AM8/4. These
names may be up to 15 characters long and are stored in nonvolatile memory in the AM8/4. In addition, the names
are stored in any disk files generated with any of the save to disk options above. Inputs or outputs with no assigned
names are listed as “No Name”. To change a name, simply click on the desired text box and enter the desired name.
While you are permitted to enter more than 15 characters in the text box, only the first 15 will be stored. To save the
changes to the AM8/4’s nonvolatile memory, you must click the Apply button and then use the Save Active Setup to
AM8/4 Preset File menu option. If you click the Cancel button, the changes you have made will not be applied. The
shortcut key for this option is Ctrl+E.
Enter Disk File Notes... - Allows you to add any notes that you want to be included in a file saved to disk. These
notes could be installation instructions, operational instructions, or any other information which might be helpful to
associate with a saved file. You’ll see the
screen shown at the right when you choose
this option:
After you enter the desired text into the text
box, choose OK to save the changes you’ve
made. Cancel will ignore the changes you’ve
made since the last time you clicked OK. Note
that to save your changes to a disk file, you
must still either use Save Preset(s) from AM8/4
to Disk File... or Save Active Setup to Disk
File... to store the notes in a disk file. The
shortcut key for this option is Ctrl+D. To save
the changes to the AM8/4’s nonvolatile
memory, you must click the Apply button and
then use the Save Active Setup to AM8/4
Preset File menu option. The shortcut key for
this option is Ctrl+E.
If you have notes already in a file and also
have added notes locally through this option,
you’ll see the following screen if you save to
either disk file or to an AM8/4 preset:
The screen will show you the notes from the selected disk
file as well as your local notes. You may choose to use the
existing disk file notes, replace them with the local notes, or
append the local notes to the disk file notes.
Print Setup... - Allows the active printer to be changed
using the standard Windows printer setup dialog. This will
set the printer which is used with the Print Tabs... menu
selection. The shortcut key for this option is Ctrl+P.
Print Tabs... - Allows any or all of the AM8/4 control panel
tabs to be printed for documentation purposes.
Update AM8/4 Firmware from Disk File - Allows newer
firmware revisions to be loaded into the AM8/4. From time
to time, new features or (heaven forbid!!) bug fixes will be
added to the AM8/4’s firmware. If a firmware upgrade is
needed in the field, the latest firmware is available from
Lectrosonics technical support. The firmware file will have
a “.s19”extension, and should be put in your LecNet
directory. If no firmware file is available in the LecNet directory, this option will be disabled. The shortcut key for this
option is Ctrl+U.
Exit - Ends the application. The shortcut key for this option is Ctrl+X.

12
Input Gain Tab
The Input Gain tab allows the
input gain and Send/React to
NOM status to be set for each of
the 8 automatic input channels,
and the input gain to be set for the
two line input channels.
Gain - Allows the input gain level
to be trimmed between +15dB
and -63dB, or Off. The gain
shown in the associated box
should be added to the preamp
gain (set by rear panel dip
switches) to calculate the total
channel gain. For example, if the
rear panel dip switches for an
input are set such that the preamp
gain is +30dB, and the input gain
box shows +5dB, the total gain
applied to that input channel
(excluding matrix crosspoint and
output gain) would be +35dB. The
background color of the input gain
box will change from white to red if the input is muted by actuation of the Mute Input function of a programmable
input. The input gain scroll bar will also be disabled while the channel is muted.
Short Cuts: A left mouse click on the gain box will set the input gain to 0dB, while a right mouse click will set the
input gain to Off.
Send to NOM - Each automatic input may be set to send to the NOM bus or not. When an automatic channel is set
to send to the NOM bus, its activity will affect the gain of all automatic inputs whose React to NOM boxes are
checked.
React to NOM - Each automatic input may be set to react to the NOM bus or not. When an automatic channel is set
to react to the NOM bus, activity
on any automatic channel whose
Send to NOM box is checked will
affect the channel’s gain.
Both boxes should be checked for
Automatic mode, and both boxes
should be unchecked for Direct
mode.
On LED - Indicates that the
attenuation applied to the input as
a result of the automatic mixing
action is less than 6dB. For
automatic inputs whose React to
NOM box is unchecked this LED is
always lit.
Level Meter - Indicates the inputs
level, taking into consideration the
Input Gain and rear panel gain
contributions.]

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8 Channel Automatic Matrix Mixer
Rio Rancho, NM –USA
Input Tone Control Tab
The Input Tone tab allows the low cut frequency and the high frequency cut or boost to be set for each of the 10 input
channels.
Low Cut - Sets the low cut corner frequency for each input channel. The low cut filter is a 6dB/octave (i.e. single
pole) filter. Frequency choices are 75Hz, 90Hz, 110Hz, 130Hz, 190Hz, 280Hz, 600Hz, and Flat.
Short Cut: A left click on the low cut box causes the frequency to be set to “Flat”.
Hi Cut/Boost - Sets the high frequency cut or boost for each input channel. The inflection point of the high fre-
quency tone control is approximately 1kHz. Choices for cut/boost are -8dB, -6dB, -3dB, Flat, +3dB, +6dB, and +8dB.
Short Cut: A left click on the hi cut/boost box causes the cut/boost value to be set to “Flat”.
Input/Output Crosspoint Matrix
Tab
The Input/Output Matrix tab sets
the input to output assignments
for the AM8/4.
Input/Output Crosspoint -
Allows the input/output crosspoint
gain to be set. Each of the first 4
rows of 11 crosspoint boxes
represent input connections which
may be set from inputs and
Expansion In LecNet port to
outputs 1-4. The last row repre-
sents the signals to send to the
Expansion Out LecNet port. To
set a crosspoint gain, simply click
on the crosspoint box at the
intersection of the desired input
and desired output. The
Crosspoint Gain frame below the
matrix will become active, and the
desired crosspoint gain may then
be selected.
Exp In is the signal from the dual 8 pin mini-DIN LecNet Expansion In connector on the rear panel of the AM8/4.
This signal would be used if another LecNet device, like a TH3 Telephone Hybrid, were connected to the AM8/4 via
the expansion cable. In this case, the TH3’s receive signal would be present at the Exp In connector. The crosspoint
gains for Exp In to any active outputs would be set to the desired gain so that the participants in the local room could
hear the far-end participant. Another application might be the addition of 8 more inputs using an AM8. In this case,
the sum of all 8 AM8 channels would appear at the Exp In connector. This signal could then be distributed as
necessary to appropriate output mixes.
The Expansion Out frame selects the signals which will be routed to the LecNet Expansion In connector. Only two
crosspoint gains, 0dB and Off, are available when sending inputs to the Expansion In port.

14
Short Cut: A right mouse click on a
crosspoint gain box will set the
crosspoint gain to 0dB.
Clear Matrix (Clr) Button -
Clears all matrix crosspoints to
the “Off”state.
Output Gain Tab
The Output Gain tab allows the
output gain levels to be set.
Gain, Outputs 1 - 4 - Allows the
output gain to be set between
+15dB and -63dB or “Off”. In
addition to the slide control,
several “quick gain set”buttons
are available for common gains.
The background color of the
output gain box will change from
white to red if the output is muted
by actuation of the Mute Output
function of a programmable input.
The output gain scroll bar, the
quick gain set buttons, and the
Master Output check box associated with the channel will also be disabled while the output is muted.
Short Cuts: A left mouse click on the gain box will set the output gain to 0dB, while a right mouse click will set the output gain
to Off.
Master Output Section
The Master Output section provides a convenient way to apply gain changes to more that one output at a time. The
six buttons (Set to Off, Set to 0dB, Decrease by 1dB, Increase by 1dB, Decrease by 5dB, and Increase by 5dB)
facilitate several common gain manipulations. Their action is applied to any output whose check box is checked. The
Select All and Unselect All buttons provide a quick way to apply gain changes to all channels simultaneously. Note
that the Increase and Decrease
buttons are push-and-hold, and
will increment or decrement the
output gain for as long as they are
held down.
Programmable I/O Setup Tab
The AM8/4 has 13 programmable
inputs and 8 programmable
outputs (available on the 15 pin D-
Sub connector on the rear panel)
which allow control and indication
of a wide variety of AM8/4 func-
tions. Pins 1-8 on the rear panel
D-Sub can be programmed to be
either programmable inputs or
programmable outputs, while pins
9-13 are only programmable
inputs. Only the parameters in
the “Applies To”section which are
associated with each specific
programmable input/output
function will be enabled as you

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8 Channel Automatic Matrix Mixer
Rio Rancho, NM –USA
select different functions. All other parameters are disabled. This eliminates invalid Function/Applies To settings.
Each of the available functions is explained below.
Hint :If the function (or any associated inputs, outputs, etc.) of a programmable I/O is changed on the control panel,
the Apply button will be enabled. The Apply button is located in the lower right hand corner of the Programmable I/O
tab. The Apply button must be clicked before any changes are actually applied to the active AM8/4 setup. Note that
you should use the Select Programmable Input Radio Buttons to select the programmable input you’d like to config-
ure before doing any configuration.
Select Programmable Input Radio Buttons 1-13 - Allows selection of which programmable I/O to change. Note
that the frame caption “Programmable Input ...”(upper left in blue) will change to indicate the programmable I/O
currently being changed.
Push Input Button - Allows a contact closure to be simulated for the current programmable input. This is useful
when testing to see that the changes you’ve made to each programmable input indeed have the intended effect.
Each click on the “Push Input...”button has the same effect as a momentary contact closure on the current program-
mable input. Note that the caption on the Push Input button always reflects the current programmable input. The
Push Input button will be disabled for any programmable inputs which are “Not Used”, “Analog In”control, or “Analog
Out”control.
Programmable I/O Status “LED”- Shows the current state of a programmable I/O. The status indicator only has
meaning for the following programmable input functions:
Analog In: LED ON - Analog In attenuation < 15dB LED OFF - Analog In attenuation >= 15dB
Increase In 1dB: LED ON - Contact closure on prog input LED OFF - No contact closure on prog input
Decrease In 1dB: LED ON - Contact closure on prog input LED OFF - No contact closure on prog input
Analog Out: LED ON - Analog Out attenuation < 15dB LED OFF - Analog Out attenuation >= 15dB
Increase Out 1dB: LED ON - Contact closure on prog input LED OFF - No contact closure on prog input
Decrease Out 1dB: LED ON - Contact closure on prog input LED OFF - No contact closure on prog input
Preset Recall: LED ON - Associated memory is active LED OFF - Associated memory is not active
Toggle Crosspoint Gain LED ON - Selected input is sent to outputs LED OFF - Selected input not sent to outputs
Mute In: LED ON - Associated input(s) not muted LED OFF - Associated input(s) muted
Mute Out: LED ON - Associated output(s) not muted LED OFF - Associated output(s) muted
Programmable Output: LED ON - Associated prog input is active LED OFF - Associated prog in is not active
Apply Button - Applies the current setting of “Function”and “Applies To”to the current programmable input. When
the Apply button is enabled, this indicates that the setting of “Function”and “Applies To”in the AM8/4 does not match
the setting of “Function”and “Applies To”shown on the control panel screen. Clicking the Apply button will load the
control panel setting into the active AM8/4 setup. This does not store the changes to a memory preset! That must
be done explicitly from the File/Save Active to AM16 Preset... file menu option. If changes are made to a program-
mable input but not applied (by clicking on the Apply button), and another programmable input is selected (by clicking
on of the Select Programmable Input buttons), all the changes to the first programmable input which were not
applied will be lost.
Programmable Input Functions :
Analog In Control - Allows one or
more input gains to be controlled by an
analog voltage on a programmable
input pin. Analog input gain control
goes from a maximum of 0dB gain to a
minimum of 30dB attenuation, plus
“Off”. The gain change resolution is
1dB. The analog in mode is ideal for
using a pot (or some other source of
analog voltage) to control input gain.
The valid voltage range in the analog
input mode is 0VDC to 5VDC. 0VDC
corresponds to “Off”(or Rear Panel

16
Minimum Input Gain, if it is programmed for less attenuation than “Off”), and +5VDC corresponds to 0dB. In addition
to analog control, this mode can be used to perform input “muting”using a simple toggle switch. To mute input(s),
simply connect the toggle switch to connect the programmable input to ground (GND pin). The screen shown below
indicates that the function of programmable input 1 is analog input control of inputs 1, 2, 8, and Line 1. Notice how
multiple inputs may be controlled by a single programmable input.
Increase In 1dB / Decrease In 1dB -
Allows one or more input gains to be
controlled by a contact closure on a
programmable input pin. Increase and
Decrease input gain control goes from
a maximum of 0dB gain to a minimum
of 30dB attenuation, plus “Off”. The
gain change resolution is 1dB. In the
case of Increase In 1dB, each contact
closure will increment the input(s) gain
by 1dB until 0dB is reached. Decrease
In 1dB will decrement the input(s)
gains by 1dB until either “Off”or Rear
Panel Minimum Input Gain is reached.
If the contact closure is pushed and
held, it will continue to increment or
decrement until it is released or the gain reaches its high or low limit. The screen shown below indicates that the
function of programmable input 1 is Increase In 1dB control of inputs 1, 2, 8, and Line 1.
Analog Out Control - Allows one or
more output gains to be controlled by
an analog voltage on a programmable
input pin. Analog output gain control
goes from a maximum of 0dB gain to a
minimum of 30dB attenuation, plus
“Off”. The gain change resolution is
1dB. The analog out mode is ideal for
using a pot (or some other source of
analog voltage) to control output gain.
The valid voltage range in the analog
output mode is 0VDC to 5VDC. 0VDC
corresponds to “Off”(or Rear Panel
Minimum Output Gain, if it is pro-
grammed for less attenuation than
“Off”), and +5VDC corresponds to 0dB.
In addition to analog control, this mode
can be used to perform output “muting”
using a simple toggle switch. To mute
output(s), simply connect the toggle
switch to connect the programmable
input to ground (GND pin). The screen
shown below indicates that the function
of programmable input 1 is analog
output control of outputs 1 and 3
simultaneously.
Increase Out 1dB / Decrease Out
1dB - Allows one or more output gains
to be controlled by a contact closure on
a programmable input pin. Increase
and Decrease output gain control goes
from a maximum of 0dB gain to a
minimum of 30dB attenuation, plus

17
8 Channel Automatic Matrix Mixer
Rio Rancho, NM –USA
“Off”. The gain change resolution is 1dB. In the case of Increase Out 1dB, each contact closure will increment the
output(s) gains by 1dB until 0dB is reached. Decrease Out 1dB will decrement the output(s) gains by 1dB until either
“Off”or Rear Panel Minimum Output Gain is reached. If the contact closure is pushed and held, it will continue to
increment or decrement until it is released or the gain reaches its high or low limit. The screen shown below indi-
cates that the function of programmable input 1 is Increase Out 1dB control of all four outputs.
Preset Recall - Allows one of the 8
AM8/4 memory presets to be recalled
by a momentary contact closure on a
programmable input pin. If you are
using two or more programmable inputs
for memory recall, you will want to set
up and apply all programmable input/
memory preset association and down-
load the active setup to all preset
memories you’ll be using. This guaran-
tees that the desired programmable
input/memory preset associations are
stored in all memories of interest. The
screen below shows that the function of
programmable input 1 is to recall AM8/4
Memory Preset 1.
Toggle Crosspoint Gain - Allows for a
temporary matrix connection to be
made between one input and any
combination of outputs, at 0dB
crosspoint matrix gain. The first
momentary contact closure on the
programmable input pin will make the
specified input-to-output(s) connection,
and the next momentary contact
closure will remove the connection. No
matrix crosspoints other than the ones
specified are changed. This toggling of
input-to-output(s) connections is ideal
for applications such as single or multi
zone paging, or other situations where
a temporary matrix connection is
needed rather than a full memory preset recall. The screen below shows input 1 being routed to outputs 1, 2, and 4.
The crosspoint gain is always 0dB. This could be a multi-zone page setup using input 1 as the paging microphone
input.
Mute In / Mute Out - Allows one or
more inputs (Mute In) or outputs (Mute
Out) to be temporarily muted. The first
momentary contact closure on the
programmable input pin will mute the
specified input(s) or output(s), and the
next momentary contact closure will
unmute them. The screen below
shows that programmable input 1 is set
to mute inputs 1, 2, 7, and 8.

18
Programmable Output - Sets one of programmable I/Os 1-8 to the programmable output mode. Programmable
outputs indicate the state of functions controlled by programmable inputs. For example, if programmable I/O 1 is set
to Mute output 1, setting programmable I/O 2 to Programmable Output and connecting its Applies To function to Prog
Input State 1 means that programmable output 2 will be active when output 1 is unmuted and inactive when output 1
is muted.
A programmable I/O whose function is set to Programmable Output will be active (i.e. conducting to ground) or
inactive (i.e. open) as follows depending on the function of the programmable input with which it is associated:
Analog In: Active - Analog In attenuation < 15dB Inactive - Analog In attenuation >= 15dB
Increase In 1dB: Active - Contact closure on prog input Inactive - No contact closure on prog input
Decrease In 1dB: Active - Contact closure on prog input Inactive - No contact closure on prog input
Analog Out: Active - Analog Out attenuation < 15dB Inactive - Analog Out attenuation >= 15dB
Increase Out 1dB: Active - Contact closure on prog input Inactive - No contact closure on prog input
Decrease Out 1dB: Active - Contact closure on prog input Inactive - No contact closure on prog input
Preset Recall: Active - Associated memory is active Inactive - Associated memory is not active
Toggle Crosspoint Gain Active - Selected input is sent to outputs Inactive - Selected input is not sent to outputs
Mute In: Active - Associated input(s) not muted Inactive - Associated input(s) muted
Mute Out: Active - Associated output(s) not muted Inactive - Associated output(s) muted
Programmable Output: Active - Associated prog in function active Inactive - Associated prog in function inactive
The screen below shows Programmable In 1 set to the Programmable Out function.
Not Used - Unprograms a programmable i/o such that there will be no action associated with it.
Remote I/O Level Controls Tab
The Remote I/O Level Controls
tab allows AM8/4 remote level
control parameters to be set.
Rear Panel Input Controls -
Allows the rear panel input gain
control adjustment range to be set
to safe levels for user adjustment.
The maximum adjustment range
of the rear panel input control
goes from 0dB to -30dB (in 1dB
steps) plus Off. The Min Gain
scroll bar allows the gain adjust-
ment range below 0dB to be
limited as needed for the applica-
tion. “Off”signifies no lower gain
limit. 0dB is the maximum value
available for Min Gain, and is
equivalent to making rear panel
input control inactive. The Gain
Preset scroll bar allows a preset
gain to be applied at power on to
any input(s) controlled by the
Increment Input 1dB or Decrement Input 1dB programmable input function. The control panel will always force the
Gain Preset to be greater than or equal to the Min Gain. The 10 boxes below the scroll bars show the current rear
panel input gain setting for each input.
Short Cuts: A left mouse click on the Min Gain box will set the minimum gain to Off (i.e. no limit on the minimum gain), while a
right mouse click will set the minimum gain to 0dB.
Rear Panel Output Controls - Allows the rear panel output gain control adjustment range to be set to safe levels for
user adjustment. The maximum adjustment range of the rear panel output control goes from 0dB to -30dB (in 1dB
steps) plus Off. The Min Gain scroll bar allows the gain adjustment range below 0dB to be limited as needed for the

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8 Channel Automatic Matrix Mixer
Rio Rancho, NM –USA
application. “Off”signifies no lower gain limit. 0dB is the maximum value available for Min Gain, and is equivalent to
making rear panel output control inactive. The Gain Preset scroll bar allows a preset gain to be applied at power on
to any output(s) controlled by the Increment Output 1dB or Decrement Output 1dB programmable input function. The
control panel will always force the Gain Preset to be greater than or equal to the Min Gain. The 4 boxes below the
scroll bars show the current rear panel output gain setting for each input.
Short Cuts: A left mouse click on the Min Gain box will set the minimum gain to Off (i.e. no limit on the minimum gain), while a
right mouse click will set the minimum gain to 0dB.
TROUBLESHOOTING
The AM8/4 is so easy to use that you’ll probably never have any trouble with it. In the unlikely event that you might,
here are a few tips for diagnosing problems:
1) If you get no sound (and the AM8/4 power is on), first check the Input Gain tab. If the number in the Gain box is
too low, you might want to turn it up a bit. If the Gain box has a red background, it means the input has been
muted. This is only possible from the programmable inputs. If you have any programmable inputs assigned
(accidentally or on purpose) to the Mute In function, now is a good time to check the state of those programmable
inputs using the Programmable I/O Setup tab. If the rear panel control for the input is set to off, you’ll get no
sound. The current gain value associated with these controls can be monitored using the Remote I/O Level
Controls tab. If all is well with all the input gain adjusting points, you should see some activity on the input level
meter when signal is present on that input.
2) So, you have input signal and the meter is dancing, but you still don’t have any sound. Check the Matrix Setup tab
to be sure that the input is actually assigned to the desired output(s).
3) The matrix is just where it ought to be, but by golly, you still don’t hear anything. Look at the Output Gain tab.
Again, if the Gain box has a red background, it means the output has been muted. This is only possible from the
programmable inputs. If you have any programmable inputs assigned (accidentally or on purpose) to the Mute Out
function, check the state of those programmable inputs using the Programmable I/O Setup tab. If the rear panel
control for the output is set to off, you’ll get no sound. The current gain value associated with these controls can
be monitored using the Remote I/O Level Controls tab.
4) If you still don’t have any sound by now, you should sweat a few bullets and check out your microphone wiring and
the wiring from your AM8/4 to the EQ or power amp. Also check to see that the power is on to all the other
equipment in the rack . If everything seems to be as it should be but still no sound, give us a call at 1-800-821-
1121 or 505-892-4501 between 8am and 5pm Mountain Time. We’ll be happy to help you troubleshoot.
FCC PART 15 NOTICE
This equipment has been tested and found to comply with the limits for a class B digital device, pursuant to Part 15
of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a
residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed
and used in accordance with the instructions, may cause harmful interference to radio communications. If this
equipment does cause harmful interference to radio or television reception, which can be determined by turning the
equipment off and on, the user is encouraged to try to correct the interference by one or more of the following
measures:
•Reorient or relocate the receiving antenna.
•Increase the separation between the equipment and receiver.
•Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
•Consult the dealer or an experienced radio/TV technician for help.

20
Wiring Diagram, 9 Pin D-Sub
LecNet Device to PC
3.5MM
Stereo Plug
9 or 25 Pin Female
D-Subminiature
S
R
T
1
2
3
4
5
6
7
8
9
LecNet Port
LecNet Device Transmit
LecNet Device Receive
Gnd
Tip
Ring
Sleeve
Host
Serial
Port
(PC)
N/C
N/C
Wiring Diagram, 25 Pin D-Sub
LecNet Port
LecNet Device Transmit
LecNet Device Receive
Gnd
Tip
Ring
Sleeve
3
2
7
1
4
5
6
20
CD
RX
TX
Gnd
RTS
CTS
RI
RX
TX
Sig Gnd
Chassis Gnd
RTS
CTS
Host
Serial
Port
(PC)
DTR
DSR
DSR
DTR
LecNet Device to AMX or Crestron
LecNet Port
AMX
or
Crestron
Port
1
2
3
4
5
6
7
8
9
LecNet Device Transmit
LecNet Device Receive
Gnd
RXD
TXD
Gnd
Tip
Ring
Sleeve
3.5MM
Stereo Plug
9 Pin Female
D-Subminiature
S
R
T
N/C
N/C
N/C
N/C
N/C
N/C
SERIAL CABLE WIRING DIAGRAMS
The serial port on the AM8/4 is a minimal RS-232
implementation. The figure shows the wiring diagram
to
accommodate interconnection with either a 9 or a 25
pin serial port on a PC or other serial device.
AMX Programming Notes
If you are using an AMX system to control your
LecNet equipment, you’ll want to purchase the
Lectrosonics PT3 Protocol Translator. The PT3
connects between the AMX bus and any LecNet
equipment. With the PT3, the LecNet equipment
looks just like native AMX equipment. The PT3 is the
fastest and most productive way to control LecNet
devices with an AMX system.