Lectrosonics DMPA12 User manual

DMPA12
Digital Power Amplifier
REFERENCE MANUAL
Rio Rancho, NM, USA
www.lectrosonics.com
Fill in for your records:
Serial Number:
Purchase Date:

DMPA12 Digital Power Amplifier
LECTROSONICS, INC.2

Reference Manual
Rio Rancho, NM 3
Important Safety Instructions
This symbol, wherever it appears, alerts you to the presence of uninsulated dangerous voltage inside the
enclosure -- voltage that may be sufficient to constitute a risk of shock.
This symbol, wherever it appears, alerts you to important operating and maintenance instructions in the
accompanying literature. Please read the manual.
1) Read these instructions.
2) Keep these instructions.
3) Heed all warnings.
4) Follow all instructions.
5) Do not use this apparatus near water.
6) Clean only with a dry cloth.
7) Do not block any ventilation openings. Install in accordance with the manufacturer’s instructions.
8) Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including
amplifiers) that produce heat.
9) Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two blades with
one wider than the other. A grounding type plug has two blades and third grounding prong. The wider blade
or the third prong are provided for your safety. If the provided plug does not fit into your outlet, consult an elec-
trician for replacement of the obsolete outlet.
10) Protect the power cord from being walked on or pinched particularly at plugs, convenience receptacles, and
the point where they exit from the apparatus.
11) Only use attachments/accessories specified by the manufacturer.
12) Use only with the cart, stand, tripod, bracket, or table specified by the manufacturer, or sold with the apparatus.
When a cart is used, use caution when moving the cart/apparatus combination to avoid injury from tip-over.
13) Unplug this apparatus during lightning storms or when unused for long periods of time.
14) Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been dam-
aged in any way, such as power-supply cord or plug is damaged, liquid has been spilled or objects have fallen
into the apparatus, the apparatus has been exposed to rain or moisture, does not operate normally, or has
been dropped.
15) WARNING -- TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DO NOT EXPOSE THIS APPARA-
TUS TO RAIN OR MOISTURE.

DMPA12 Digital Power Amplifier
LECTROSONICS, INC.4
Note: This equipment has been tested and found to comply with the limits for a
Class A digital device, pursuant to Part 15 of the FCC Rules. These limits are
designed to provide reasonable protection against harmful interference when the
equipment is operated in a commercial environment.
This equipment generates, uses, and can radiate radio frequency energy and,
if not installed and used in accordance with the instruction manual, may cause
harmful interference to radio communications.
Operation of this equipment in a residential area is likely to cause harmful inter-
ference in which case the user will be required to correct the interference at this
own expense.

Reference Manual
Rio Rancho, NM 5
Contents
Important Safety Instructions.............................................................................................................................................................3
General Overview ................................................................................................................................................................................6
DMPA12 System Configuration..........................................................................................................................................................8
DMPA12 Functional Block Diagram ...................................................................................................................................................9
Output Processing .............................................................................................................................................................................10
DMPA12 Controls and Features.........................................................................................................................................................11
Rear Panel .........................................................................................................................................................................................12
Installing LecNet2 Software and USB Driver ....................................................................................................................................13
USB Driver Installation (Windows 2000)............................................................................................................................................15
Using the Update Wizard ...................................................................................................................................................................16
Initial Setup ..........................................................................................................................................................................................18
Connection.........................................................................................................................................................................................18
DMPA12 System Setup Tabs...............................................................................................................................................................19
Activity Tab .........................................................................................................................................................................................19
Source Tab .........................................................................................................................................................................................20
Delay Tab ...........................................................................................................................................................................................21
Filters Tab...........................................................................................................................................................................................22
Compressor Tab.................................................................................................................................................................................24
Gain / Level Tab .................................................................................................................................................................................26
Limiter Tab..........................................................................................................................................................................................28
Rear Panel Control Tab ......................................................................................................................................................................30
DMPA12 Menus and Functions ..........................................................................................................................................................34
Setting up Front Panel controls..........................................................................................................................................................34
DMPA12 Serial Interface and General Commands ...........................................................................................................................36
DMPA12 General Commands............................................................................................................................................................36
DMPA12 Output Compressor Commands .........................................................................................................................................43
DMPA12 Output Limiter Commands ..................................................................................................................................................44
DMPA12 Programmable I/O Commands ...........................................................................................................................................45
DMPA12 Front Panel Control .............................................................................................................................................................48
DMPA12 Rear Panel Control Commands ..........................................................................................................................................50
DMPA12 Command Grammar Rules..................................................................................................................................................52
Macros and Macro Control .................................................................................................................................................................53
Rear Panel Control with Hardware.....................................................................................................................................................54

DMPA12 Digital Power Amplifier
LECTROSONICS, INC.6
General Overview
The architecture of a LecNet 2 sound system is built
around a powerful digital matrix and bus structure com-
mon to all DM Series components interconnected in a
system. Data and audio signals are shared among the
components through a digital bus called DANI (Digital
Audio Network Interface).
In order to understand the power and functions avail-
able with this architecture it is helpful to think of the
matrix as a separate entity from the hardware. Con-
ceptually, a DM processor is simply a hardware-based
tap into the digital matrix to interface various types of
microphones and audio equipment into the signal flow.
The DANI bus interconnects the processors to allow
them to share information about each input and output
and to distribute the audio.
Multiple DM processors are “stacked” to configure
larger systems, with one unit configured as the Mas-
ter at the “top” and the others as Slaves. There is no
limit to the number of units that can be stacked to add
inputs to a system. The number of outputs is limited to
a maximum of 24. Literally hundreds of inputs can be
configured with no “gas gauge” for DSP resources and
still less than 4 ms of latency. The choice of processor
model determines the number of final mix outputs at the
Master unit at the top of the stack.
When multiple DM processors are stacked, each unit
participates with the digital structure in several ways:
• Delivering audio signals from its input terminals into
the forward-propagated submix bus
• Passing back-propagated final mix signals from the
unit above it to the next unit below it
• Applying gain and signal processing to the audio
signals at its input terminals
• Delivering audio signals to its output terminals as
selected by the setup
• Applying signal processing to the signals routed to
its output terminals
• Receiving and transmitting data required for the
automatic mixing process in the matrix
The digital matrix is common to all processors in
the stack, with automatic mixing taking place at the
crosspoints in the digital matrix. The output of each
crosspoint is then available at a variety of output termi-
nals on various processors in the stack.
The DMPA12 digital power amplifier takes its input from
the DANI bus, with each output able to source from the
back or forward propagated signals (see block diagram
on page 8). This architecture provides exceptional flex-
ibility to accommodate a wide variety of applications.
Automatic Mixing Matrix
DM Series
Processor
Master
Slave
Slave
DM Series
Processor
DM Series
Processor

Reference Manual
Rio Rancho, NM 7
The LecNet 2 product family includes a variety of com-
ponents to address a wide variety of applications. Differ-
ent processor models interface with the digital matrix in
different manners.
Four basic matrix processor models are available:
• DM812 8 in/12 out
• DM1612 16 in/12 out
• DM1624 16 in/24 out
• DM84 8 in/4 out
Each of these models provides mic/line inputs, exten-
sive signal processing and differential balanced outputs.
Outputs are forward propagated to the Master unit in a
stack, and the first 12 outputs are also back propagated
to the Slaves in the system.
The DMTH4 telephone hybrid and DM84 processor
contribute to all 24 forward propagated channels deliv-
ered to the Master in the system, even though each of
them have only 3 or 4 physical outputs. The signals for
these 3 or 4 outputs are selected from the first 12 final
mixes back propagated from the Master.
Signal flow through the DANI bus
Master
Slave
Slave
Slave
Slave
EXPANSION
A B
TX RX
RX TX
EXPANSION
A B
TX RX
RX TX
EXPANSION
A B
TX RX
RX TX
EXPANSION
A B
TX RX
RX TX
EXPANSION
A B
TX RX
RX TX
Audio Final Mix and
Data Back Propagation
Audio Submix and
Data Forward Propagation
The DMPA12 digital power amplifier takes its inputs
from the DANI bus. It can access either the first 12 back
propagated signals from the system Master unit or the
24 forward propagated channels.
The output amplifiers are a Class D type in a differential
balanced configuration with each device providing two
channels, sharing a ground on a common connector.
The device is impervious to damage from shorts or
thermal overload, and can drive loudspeaker loads from
4 ohms and up. The outputs can also be wired in paral-
lel to double the available output power.
Because of the high efficiency of the Class D design,
no special ventilation or fans are necessary, even in
continuous duty at any power level.

DMPA12 Digital Power Amplifier
LECTROSONICS, INC.8
Two DMPA12 units configured as Master and Slave
at top of stack to handle up to 24 outputs
Slave
Slave
Slave
Slave
Slave
EXPANSION
A B
TX RX
RX TX
EXPANSION
A B
TX RX
RX TX
EXPANSION
A B
TX RX
RX TX
EXPANSION
A B
TX RX
RX TX
EXPANSION
A B
TX RX
RX TX
DMPA12 Slave
EXPANSION
A B
TX RX
RX TX
DMPA12 Master
EXPANSION
A B
TX RX
RX TX
Output Channels 1 - 12
Output Channels 13 - 24
Audio Submix and
Data Forward Propagation
DMPA12 configured as Slave at bottom of stack
Master
Slave
Slave
Slave
DMPA12 Slave
EXPANSION
A B
TX RX
RX TX
EXPANSION
A B
TX RX
RX TX
EXPANSION
A B
TX RX
RX TX
EXPANSION
A B
TX RX
RX TX
EXPANSION
A B
TX RX
RX TX
Audio Final Mix and
Data Back Propagation
Output Channels 1 - 12
Back Propagation - 12 channels
The DMPA12 digital power amplifier is
typically configured as a Slave in the
system using the first 12 back propa-
gated final mix signals labeled “Final
Mix” in the GUI.
See the RED signal path.
DMPA12 System Configuration
Forward Propagation - 24 channels
If more than 12 outputs need to be
amplified, two DMPA12 units can be
configured at the top of the stack, one
as a Master and one as the uppermost
Slave. In these positions, both units
can make use of the forward propagat-
ed signals from the Slave units below
them labeled “FP Main Mix” in the GUI.
See the BLUE signal path.
24 Channels
12 Channels

Reference Manual
Rio Rancho, NM 9
SHARC is a registered trademark of
Analog Devices, Inc.
USB
Port
RS-232
Port
Prog I/O
Port
Micro
Controller
Prog I/O Conn
DB25
LecNet 2 Conn
1/8 '' Jack
Front & Rear
USB B Conn
Control Signals
8
11
12
A/D
Output Volume Control Pots
12
Tx
Tx
Rx
Rx
Digital
Audio
Network
Interface
(DANI)
12 + 2 Submix + Mix Control
12 + 2 Submix + Mix Control
12 + 2 Mix + Mix Control
12 + 2 Mix + Mix Control
Sync Audio Frame Sync
Quad RJ-45 Conn Pink Noise Generetor
1 kHz Tone Generator
Third Generation
SHARC
®
DSP
Out 1
Out 2
Out 3
Out 4
12 output tricolor
signal indicator
LEDs
Signal Processing D/A
Signal Processing D/A
Signal Processing D/A
Signal Processing D/A
Signal Processing D/A
Signal Processing D/A
Signal Processing D/A
Signal Processing D/A
Signal Processing D/A
Signal Processing D/A
Signal Processing D/A
Signal Processing D/A
Out 12
Out 11
Out 10
Out 9
Out 8
Out 7
Out 6
Out 5
Off: No signal
Green: Signal present
Orange: Compressor active
Blinking orange: Fault
Red: Limiter active
Blinking red: Channel muted at front panel
DMPA12 Functional Block Diagram

DMPA12 Digital Power Amplifier
LECTROSONICS, INC.10
Output Processing
Extensive signal processing is available at each output,
adding to the processing available in the mixer/proces-
sors in the system. This is especially useful when a
variety of loudspeaker types are being used.
Output Source Select
The digital matrix delivers the audio signals used in
normal operation. The pink noise source can be used
for sound masking during operation, and for equaliza-
tion during setup. The tone generator is used for level
adjustments and signal routing diagnostics.
Output Signal Processing Stages
Each output channel provides a delay, nine filters, plus
a compressor and limiter to idealize the channel for
its function in the sound system. (See Typical Output
Signal Processing Block.)
Digital Delay
Delay on the output signal is normally used for time
alignment when loudspeakers are positioned in different
locations with overlapping coverage patterns that cause
comb filtering. The signal can be delayed up to 200 ms
in 0.5 ms increments to eliminate comb filtering and
improve intelligibility.
Filters
Up to nine filters can be implemented at each output to
idealize the output channel equalization and implement
crossover networks for bi-amped or tri-amped loud-
speaker systems.
The filter types include:
Low pass
High pass
Band pass
Parametric EQ
Low shelving
High shelving
Filter slopes can be selected with 6 or 12 dB per octave
Butterworth or Bessel parameters. Multiple filters can
be assigned to creater steeper slopes in 6 dB steps.
Compressor
A versatile compressor is provided at each output to
control the average level and dynamics of the audio sig-
nal, and restrict the maximum output level to optimize
the channel for its purpose.
Compressor adjustment parameters include:
Threshold
Time constant
Compression ratio
Makeup gain
Limiter
A sophisticated limiter with adjustable threshold and
time constant parameters can be set up for each output,
which is normally used to protect a loudspeaker system
and reduce distortion and amplifier overload.
Limiter adjustment parameters include:
Threshold
Time constant
The limiter implementation is based on an RMS level
detector controlled by a single time constant parameter.
This is an adaptive design which responds to vary-
ing rates of change in the signal level by dynamically
adjusting the attack and release times for best perfor-
mance.
Output Gain and Level Indicator
The level of each output can be adjusted over the full
range in 1 dB steps. A bar graph is provided in the GUI
to accurately indicate the output level as it operates.
See the detailed description on page 26 under the topic
entitled Gain/Level Tab.
Typical Output Signal Processing Block
Activity Indicator
Output Gain
-70 - +20 dB
1 dB steps
Nine Filter
Stages
Delay Compressor Limiter
Level Meter
Off, LP, HP, BP,
PEQ, LS, HS
6 or 12 dB/oct.
Butterworth or Bessel
when applicable
0 – 200 ms
0.5 ms steps
Threshold
Comp. Ratio
Time Constant
Indicator
Activity Indicator
Gain Reduction Indicator
Threshold
Time Constant
One of 12 Output Signal Processing Blocks