Audio Control CM Series User manual

CM Series Ampliers
CM2-750, CM3-750, CM4-750
2, 3, 4 CHANNEL, LOW IMPEDANCE / 70V / 100V
POWER AMPLIFIERS
FOR RESIDENTIAL AND COMMERCIAL APPLICATIONS
Installation Manual

2
Important Safety
Instructions
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. In-
stall 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 ampliers) that
produce heat.
9. Protect the power cord from being walked
on or pinched particularly at plugs, conve-
nience receptacles, and the point where
they exit from the apparatus.
10. Only use attachments/accessories speci-
ed by the manufacturer.
11. Unplug this apparatus during lightning
storms or when unused for long periods of
time.
12. Refer all servicing to qualied service
personnel. Servicing is required when
the apparatus has been damaged in any
way, such as power-supply cord or plug is
damaged, liquid has been spilled or objects
have fallen into the apparatus, the appara-
tus has been exposed to rain or moisture,
does not operate normally, or has been
dropped.
13. This apparatus shall not be exposed to
dripping or splashing, and no object lled
with liquids, such as vases or glasses, shall
be placed on the apparatus.
The lightning ash with arrowhead
symbol within an equilateral triangle
is intended to alert the user to the
presence of uninsulated “dangerous voltage”
within the product’s enclosure, that may be
of sucient magnitude to constitute a risk of
electric shock to persons.
The exclamation point within an
equilateral triangle is intended to alert
the user of the presence of import-
ant operating and maintenance (servicing)
instructions in the literature accompanying the
appliance.
Caution: to reduce the risk of electric shock,
do not remove the top cover. There are no
user-serviceable parts inside. Refer servicing to
qualied personnel.
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 radi-
ate radio frequency energy and, if not installed
and used in accordance with the instructions,
may cause harmful interference to radio com-
munications. However, there is no guarantee
that interference will not occur in a particular
installation.
If this equipment does cause harmful interfer-
ence to radio or television reception, which can
be determined by turning the equipment o
and on, the user is encouraged to try to correct
the interference by one or more of the follow-
ing measures:
• Reorient or relocate the receiving antenna.
• Increase the separation between the equip-
ment and the receiver.
• Connect the equipment into an outlet on
a circuit dierent from that to which the
receiver is connected.
• Consult the dealer or an experienced radio/
TV technician for help.
CAUTION: Changes or modications to this
device not expressly approved by AudioControl
Inc. could void the user’s authority to operate
the equipment under FCC rules.
Recycling notice: If the time comes
and this apparatus has fullled its
destiny, do not throw it out into the
trash. It has to be carefully recycled
for the good of mankind, by a facility specially
equipped for the safe recycling of electronic
apparatii. Please contact your local or state
recycling leaders for assistance in locating a
suitable nearby recycling facility. Or, contact us
and we might be able to repair it for you.
Important Safety Instructions

3
Installation Manual
CM2-750, CM3-750, CM4-750
CM SERIES
Table of Contents
Table of Contents
Important Safety Instructions ...... 2
Table of Contents ................ 3
Introduction..................... 4
Features ........................ 4
Complimentary Features .......... 6
Quick View ...................... 7
Front Panel ..................... 7
Rear Panel ...................... 7
Getting Started .................. 8
Installation Examples ............. 8
Front Panel Features.............. 13
Rear Panel Features ............. 15
Speaker and Wiring Impedance ..... 18
12 Volt Trigger Ins and Outs ........ 19
Ventilation ...................... 21
Internet Connectivity and Control... 22
Acoustics ....................... 36
Equalization..................... 37
Advanced Discussions............. 40
Troubleshooting ................. 42
Block Diagram ................... 44
Specications ................... 45
Service ......................... 46
The Warranty.................... 47
The Crossover Two-Step ........... 52
©2021 AudioControl Inc., all rights reserved.
Based on a dream-sequence involving the technical writer, the 1978
FA Cup Final, two pints of lager and a packet of crisps
Network Settings
Default IP Address 192.168.0.249

4
Flowery Marketing Introduction
Congratulations!
If you are reading this user’s manual then it is
likely that you are involved in the installation
of an AudioControl CM Series amplier. This
amplication product was designed to allow
the user to maximize the performance of any
distributed audio speaker system, whether
you are using traditional low impedance (LoZ)
or 70/100 volt (HiZ) speaker systems…or both.
The AudioControl CM Series ampliers were
designed to optimize the performance of to-
day’s residential and commercial architectural
speakers systems, including in-wall, in-ceiling,
pendants, invisible, plus high performance
outdoor audio systems. Great sound in your
backyard and elsewhere is amazing!
The CM Series ampliers are unique in the
realm of 70-volt options because they oer
DSP control and signal matrixing capabil-
ities developed by AudioControl for their
award-winning Director Series ampliers. Fea-
tures like ethernet control, analog and digital
inputs, full DSP capabilities including graphic
and parametric equalization, crossover lters,
speaker proles plus audio matrixing, make
these a truly special family of ampliers.
AudioControl’s engineers have matched these
unique features around an amplier platform
that is designed to maximize power output
levels, with minimal heat dissipation, making
the CM Series “one cool customer” which is
critical in the rack design of many systems.
AudioControl has long been known for “Mak-
ing Good Sound Great,” so maximum audio
performance was a key design element for the
CM Series. While some companies consider
whole house audio just for background sound,
our approach is to deliver an amazing audio
performance of music throughout the entire
system.
The CM Series ampliers are designed and
manufactured in the USA by AudioControl,
the only electronics company in the world
that specializes in ampliers, equalizers,
signal processors and audio analyzers. Our
passion for high quality, meticulous attention
to detail, and pro sound heritage shows itself
in the dozens of awards we have won for our
designs, products, and service over the past
four decades.
Introduction
This is a professional installer’s manual and
covers all members of AudioControl’s CM Se-
ries family, and is designed to assist in getting
the optimum performance out of this unique
product. The CM Series models are similar in
operation, aside from the number of inputs,
outputs and channel counts, and this manual
covers all models. We assume this product is
being professionally installed by someone who
is experienced with multi-channel ampliers,
70 volt installation practices, and Ethernet
protocol, as this unit will require an ethernet
connection during setup.Your friend with an
“awesome set of tools” is probably not the
best candidate to install these units.
Now, as when we began, our greatest satisfac-
tion is our reputation for sonic excellence and
reliability among people just like you through-
out the world. We hope you enjoy the ride!
Features
Here are some of the features that make the
USA designed and manufactured AudioCon-
trol CM series ampliers very unique, unlike
any other amplier solutions:
• Dual Mode Amplication - The unique
CM series ampliers are designed to play
into either high impedance (HiZ) 750
watts into 70 volt loads or into traditional
(LoZ) applications of 4 or 8 ohm speak-
ers, 625 watts per channel, stable into
2 ohms. A simple selector switch allows
the user to change the channel output
independently to best match up with the
speaker system.
• High Power Levels - The CM Series has
the ability to produce 750 watts of power
into all channels, into a 70 Volt load.
Optionally the constant wattage design
of the CM ampliers can also produce
625 watts per channel into either 4 or 8
ohm loads allowing it to operate as an
excellent amplier for traditional LoZ
speaker systems.

5
Installation Manual
CM2-750, CM3-750, CM4-750
CM SERIES
Features
• Flexible Input Options - Most ampli-
ers are equipped with only unbalanced
inputs. The CM Series is a “swiss army
knife” of ampliers, so it is equipped with
both types of analog audio inputs. In ad-
dition, we have equipped the CM series
with inputs for digital audio sources so
you can easily interface your favorite
digital streams without a hodgepodge of
wiring terminations. The high-resolution
digital inputs accept 32-96 kHz, 16/24-bit
digital signals. There are 2 mic input
channels as well, to take full advantage
of the SDS feature in certain applica-
tions.
• Powerful DSP Control - The CM Series
was designed to operate with Audio-
Control’s legendary DSP controls. Users
have the ability to select speaker proles,
adjust graphic and parametric equaliza-
tion controls, plus assign hi-pass and low-
pass crossover settings allowing the user
to optimize each output channel. For
example, channel 1 is for satellites and
channel 2 could power subwoofers! Ad-
ditionally, presets, volume level controls
and full matrixing functions are available
to allow users maximum operation from
one single chassis.
• Dante Spoken Here - The CM Series
can be ordered with an optional Dante
port which will allow connectivity with
any other Dante-equipped device over a
network using a single Cat-5 cable. This
allows the CM series to share hi-res audio
with other Dante-enabled ampliers
from AudioControl and others. Cabling is
kept very simple and connectivity is solid.
If you have any questions about audio
capabilities, Dante technology was used
at the recent Grammy awards so great
sound is the goal!
• So Cool…. The CM Series was designed
to not only be a top performing amplier
but is also designed to be a cool custom-
er. A unique GaN design from Audio-
Control allows the CM series to deliver
maximum power to each output channel
while allowing the units to operate at
moderate temperature levels. This allows
users lots of installation exibility when
it comes to installing the CM series in
rack applications. You can actually rack 4
units on top of each other!
• Take Control WithThe CM Series - The
IP equipped CM series allows a user to
control the system via Telnet commands
or via control drivers/proles from
3rd party automation companies like
Crestron, Control 4, Elan and RTI. With
this level of control, users can control
and query almost all the functions, mute
zones, change source inputs, recall EQ
presets, check line voltage, display pro-
tection logs, and even trigger an email
if something goes wrong. This is a great
way to provide an extra layer of service
and monitoring for your customers.
• Self Resetting Protection Features -
Protection features for the CM Series
are extensive and include thermal, short
circuit, clipping, ultrasonic and DC oset
among others. If the fault is removed,
the unit resets. Plus, it can send you an
email if something happens.
• Pacic Northwest Heritage - Like all
AudioControl ampliers, the CM series
ampliers were conceived, designed and
manufactured in the USA at our amazing
audio technodrome in the Pacc North-
west. We are very proud of that fact but
what is more important is the care we
craft in at every step, and the extensive
knowledge we have in all aspects of the
product. With this in mind we support
the CM Series with an industry leading,
conditional ve year warranty.
• Audio Legends - Whenever our amplier
engineers and DSP engineers visit and
hob-nob with their fellow audio wizards
at trade shows and audio conferences,
there is an audible and reverent hush
as they enter the room. They are asked
to sign autographs on tee shirts, pets,
photos, and (at the end of the evening)
on heavy bills from restaurants and
bars. They are included in many seles
taken by their adoring fans and industry
colleagues. At technical documentation
conferences, the manual writer is often
ceremonially debagged and thrown
into the hotel swimming pool by fellow
technical writers.

6
Complimentary Features
Features continued
• Expansive input array: Analog unbal-
anced inputs, balanced inputs, micro-
phone preamp stage, digital inputs
and an optional Dante card.
• Exceptional high power outputs with
independent LoZ and HiZ exibility
and up to 750 watts per channel of
prodigious output power
• Enhanced conguration and control:
On board web page oers complete
control over each input and output
setup and operational parameters
to dene an immersive audio experi-
ence in any residential, outdoor, com-
mercial and touring space. Graphic
and parametric EQs, highpass/low-
pass/bandpass ltering, trim control,
input sensitivity – the works!
• Matrix: dynamic input routing to any
output via web control or third party
control.
• Eciency: Harnessing new technolo-
gies of gallium nitride as power devic-
es, the amp exceeds 95% eciency in
its Class D conguration. Nothing like
it on the planet! With that eciency,
you get some cool operation (rela-
tively speaking of course as it is 3000
watts!)
• 3rd Party control: Seamlessly inte-
grating into common third-party
control systems.
• Dante Spoken Here: 16x16 Dante
inputs and outputs with the optional
card, oers system integration be-
tween other AudioControl CM and
Director series ampliers, as well as
integration into 3rd party control
systems.
• Speaker proles: On board speaker
prole, ready to go out of the box –
major brands at your nger tips to
speed up the install to get the great-
est sound!
• Loop outputs: Allows daisy chaining
for unbalanced, balanced and digital
inputs.
• Digital Outputs: Full preamp con-
trolled digital output to send down-
stream to other AudioControl amps
– signal routing, EQ, volume control
– all the goods you need.
• Master 12v trigger: Turn on and o in
the good old analog way.
• 12v output: Oers a method to create
Failover trigger via the 12v output
where, if power loss is encountered
with this main system, the line goes
low which can trigger another backup
amplier running o a generator for
critical public address systems.
• Front to Back cooling: Conforming
to standard commercial practice,
cooling is forced air from the front to
back.
• Grouping: run channels in tandem
with source switching and volume
control.
• Stackable with other CM series and
AudioControl amps.
• Signal sensing allows for trouble-free
operation.

7
Installation Manual
CM2-750, CM3-750, CM4-750
CM SERIES
Quick View
Quick View
Front Panel
4. Zone Status LED
5. Zone Level LED Ladder
6. Rack Mount Ears
10. Output Conguration Jumper
11. Zone Triggers
12. Main Triggers
13. Digital Inputs Coax/Optical with
signal-present LEDs
14. Digital Coaxial Outputs
15. Master Reset
16. Dante Connection
17. Ethernet Connection
Rear Panel
1. AC Power Switch
2. AC Input
3. 1-2 Mode Switch Mic/Line
4. Analog Coaxial Inputs
5. Analog Input Terminals
6. Signal Present LEDs
7. Analog Coaxial Loop Outputs
8. Analog Loop Output Terminals
9. Speaker Level Output Terminals
1. Power LED
2. Protection LED
3. Ethernet Status LEDs
12
46
53
1110 12 13 14 15 16 17
21 5 76 83 4
9

8
Getting Started
1. Turn o power to all com-
ponents before making any
connections.
2. When making connections, des-
ignate red RCA plugs as right, and
designate white, black, or grey plugs
as left. This is a good idea for all sig-
nal connections made in your audio
system. The key is consistency. Stick
with the same color coding and you’ll
reduce possible problems.
3. Whenever possible, keep power
cords away from signal cables to pre-
vent induced hum. This is especially
important if you bundle the cables to
keep the installation neat looking.
4. Use quality interconnect cables. We
know from experience that really
cheap cables can cause a multitude
of problems. They tend to break
inside or corrode, causing a loss of
signal or hum. They also have poor
shielding.
5. If you need to run the RCA audio
cables more than 20 feet, consider
using an active balanced line driver
for the signals. This will provide
better noise rejection against nasty
things like hum, spikes, local talk
radio, and metaphysical paranormal
phenomena, etc. The AudioControl
balanced line driver components
(BLD-10, BLR-10 and BLX-10) are an
excellent way to send audio over long
distances with standard Cat-5 wiring.
Check them out at audiocontrol.com.
6. If you are using the digital inputs,
and running higher resolution sam-
ple rates (96 kHz), use high-quality
digital interconnect cables.
Getting Started
7. Dance in a fairy circle at midnight, on
the rst full moon of the new year.
Ask Queen Mab for the IP address.
8. Connect the unit to the network with
an Ethernet cord, preferably one in
good condition without a broken tab
or covered in honey or Marmite®.
9. Open your favorite internet browser
and open the web server within the
unit. It will show all features and
controls of the unit.
Installation Examples
The next pages show some typical instal-
lations of the three dierent ampliers
in this series: CM2-750, CM3-750, and
the CM4-750. These include a mixture of
channels running 70V speakers and chan-
nels running low impedance speakers. A
system using the optional Dante card is
also shown.

9
Installation Manual
CM2-750, CM3-750, CM4-750
CM SERIES
Installation Examples
CM2-750 Installation with 70V speakers
CM2-750 Installation with 70V speakers and
subwoofers
70V Speakers
Taps 50W or less Taps 50W or less
Set both switches UP
for Mode A = 70V
70V Speakers
Sonos 2Sonos 1
Analog
Out
Digital
Out
70V Speakers
Taps 50W or less
Subwoofers
4 Ohms combined
Switch 1 UP for Mode A = 70V
Switch 2 DOWN for Mode B = Low impedance
Sonos 2Sonos 1
Analog
Out
Digital
Out

10
Installation Examples
CM3-750 Installation with 70V speakers and
subwoofers
Taps 50W or less
70V Speakers
Taps 50W or less
Subwoofers
4 Ohms combined
Sonos 2
Mic
Sonos 1
Digital
Out
Set Switch
to Mic
Source 3
Analog
Out
Analog
Out
Switch 1 and 2 UP for Mode A = 70V
Switch 3 DOWN for Mode B = Low impedance

11
Installation Manual
CM2-750, CM3-750, CM4-750
CM SERIES
Installation Examples
CM4-750 Installation with 70V speakers and
subwoofers
Sonos 2
Mic
Sonos 1
Digital
Out
Set Switch
to Mic
Taps 50W or less
70V Speakers
Taps 50W or less
Subwoofers
4 Ohms combined
Subwoofers
4 Ohms combined
Source 3
Analog
Out
Analog
Out
Switch 1,2 UP for Mode A = 70V
Switch 3,4 DOWN for B = Low impedance

12
CM4-750 Installation of 2 units with the optional
Dante card
CM2-750, CM3-750, CM4-750 rear panel dierences
Sonos 1 Sonos 2 Source 3 Source 5
Source 4
Digital
Out
Analog
Out
Analog
Out
Analog
Out
Analog
Out
Dante port option installed
Speaker Connections
Speaker Connections
Dante port option installed
Network Connection Cat5
Network Connection Cat5
CM2
CM3
CM4
This illustration shows the
rear panel dierences be-
tween the 3 ampliers. Each
channel has its own speaker
output terminal pair, a zone
status LED, a mode switch
and zone trigger terminal
pair.
Installation Examples

13
Installation Manual
CM2-750, CM3-750, CM4-750
CM SERIES
Front Panel
Front Panel Features
1. Power LED – This dual color LED indi-
cates when the unit is in standby, on,
or o.
Red: the unit is in standby mode
and is ready to be turned on
via Ethernet or 12V triggering
Blue: the unit is on
OFF: the unit is powered o
2. Protection LED – This red LED will
illuminate briey during turn on/o
phases, and if a fault is detected in any
amplier or the power supply (such
as overheating, over-current, or DC
oset). If a fault is detected, then the
unit will go into its protection mode to
prevent any damage to loudspeakers,
and to allow cooling.
3. Ethernet LEDs – These indicate the
status, readiness, and willingness, of
the Ethernet communications protocol
to (getting all technical for a moment)
strut its funky stu. The green LED
glows when the Ethernet is connected
and operational, and the yellow LED
blinks during data activity.
4. Zone Status LED – This dual-color
LED indicates when the zone is in fault
mode, active, or in standby.
Red: The zone has detected a fault,
such as a DC oset or a load
short circuit
Blue: The zone is active
OFF: The zone is in standby
5. Zone Level LEDs –These three LEDs
light from the bottom to the top
depending on the zone’s output level
(-33, -20, -10 dBFS).
The 2-channel CM2-750 amplier
is shown here. The 3 and 4 channel
models have LEDs displays for each
channel.
6. Rack Mount Ears – The unit comes
supplied with removable rack mount
ears. These allow the unit to be rack
mounted in a standard 19” wide rack,
with a 2U height. Use standard rack
mount screws and washers to secure
the unit in a rack. The unit does not
have to be supported at the rear if the
rack is located in a xed location.
To remove the rack ears (making the
unit 17” wide), rst unplug the power
cord, and then locate and undo the
four screws securing each ear to the
side of the chassis, and remove the
ears. Replace the screws securely back
into the chassis. Do not remove any of
the other screws from the chassis or
top cover. There are hazardous voltag-
es inside the unit. Keep the rack ears
in a safe place. While on the subject
of good advice, don’t forget to phone
your mom regularly and keep in touch
with people who love you. Our tech
support team do get lonely at times.
12 4653

14
Front Panel
LED Function Table
LED Color Description
Red the unit is in standby mode
Blue the unit is on
O the unit is powered o, or all the lights are o in town
Red the unit has detected a fault and is in protect mode*
O the unit is operating normally, or it is powered o
ZONE LEDs Color Description
Blue -10 dBFS zone output level
Blue -20 dBFS zone output level
Blue -33 dBFS zone output level
Blue/Red Blue or Red ash shows technical writer’s heartbeat –
this is normal, except when the Seahawks are playing
Red The zone has detected a fault, or a smooth-jazz saxo-
phone solo, and is in protect mode
Blue The zone is active
O The zone is in standby
*The protection LED also comes on for a short time during power up or down

15
Installation Manual
CM2-750, CM3-750, CM4-750
CM SERIES
Rear Panel
Rear Panel Features
When rack-mounting the unit,
make sure that the power cord
and the AC power switch remain
readily accessible.
1. AC Power Switch – This switch shuts
o the main AC power. Normally the
only time you need to turn this o is
if the system is going to be shut down
for an extended period of time. Use
the Ethernet or master trigger inputs
to switch the unit between standby
and on.
Also turn the power switch o during
lightning storms, wind storms with
frequent power outages, or when a
giant metal space robot is heading for
the power station again. They do that
a lot.
2. AC Input – Connect the supplied AC
power cord securely to this input. Plug
the other end into an AC mains outlet
of the correct voltage rating for your
unit. They are either 100 -120 VAC (50
– 60 Hz) or 220 – 240 VAC (50 – 60 Hz);
look at the check box to see how your
unit has been congured. The voltage
setting is not user-settable. This unit
is a class 1 device, do not defeat the
safety ground connection or use a
power cord that does not have the
safety ground pin.
3. 1-2 Input Mode Switch – If the analog
inputs are line-level, leave this in
the OUT position. If they are micro-
phone-level, push this IN. (Check the
position of this switch if your levels
seem too low, or too high.) Check your
hair as well, so you will always look
fabulous.
4. Analog Inputs – These are analog RCA
inputs. Analog signals enter here from
audio sources such as CD players, DVD
players, and TV outputs, or micro-
phones, and may be selected to play
in a zone, or both zones at once, and
the digital outputs. This extraordinary
exibility is made possible by taking
ballet lessons from an early age, and
the unit’s web server interface menu.
5. Analog Input Terminals – These ana-
log inputs use terminal blocks, if you
prefer things that way. They may be
wired balanced or unbalanced.
6. Signal Present LEDs – These light
whenever analog signals are present at
the inputs.
7. Analog Loop Outputs – These analog
outputs are copies of the analog input
signals. They can be used to send the
analog input signals to other compo-
nents in your system.
1110 12 13 14 15 16 17
21 5 76 83 4
9

16
Rear Panel
8. Analog Loop Output Terminals –
These are analog RCA outputs using
terminal blocks.
9. Speaker Outputs – Each channel has a
2-pin connector that allows easy con-
nection of loudspeakers.The LEDs will
light when each zone is active.
10. Mode A/B – The unit can run a 70V line
in Mode A, or low impedance in Mode
B, either in stereo or mono operation.
The 2-channel amplier has 2 switches
as shown. The 3-channel model has 3
switches, and the 4-channel model has
4, in French, this is 4.
Switches UP for Mode A = 70V
Switches DOWN for Mode B = Low Impedance
11. Zone Trigger Input – The individual
zones can be turned on by applying a
+12Vdc trigger voltage to these inputs.
12. Main Trigger – If you are not using the
Ethernet connection to turn the unit
on, then you can use this 3-pin block
connector to turn on the unit or place
it into standby mode. For example,
you could have an external device such
as one of our glorious AudioControl
home theater receivers, turn on the
unit when it is turned on.
If you are not using the Ethernet con-
nection to turn on the unit, and there
is no trigger voltage present at any of
these trigger inputs, then the unit will
be in standby, with zones muted.
13. Digital Inputs – There are two co-
axial and two optical digital inputs:
A and B. The Signal Present LEDs light
up whenever a digital input signal is
present.
The digital signals are transferred
directly to the advanced DSP section,
and are then available to a zone or
both zones at the same time. The
digital inputs are selected for any zone
using the unit’s web page interface.
14. Digital Outputs – These two S/PDIF
digital outputs use standard RCA coax-
ial connectors.
The digital signals from each of these
outputs can be a copy of any zone’s
input pair (converted internally from
analog to digital), or a copy of the
digital inputs. This is selectable using
the unit’s web page interface. For an
example, these outputs can be sent to
the digital inputs of another unit.
1110 12 13 14 15 16 17
21 5 76 83 4
9

17
Installation Manual
CM2-750, CM3-750, CM4-750
CM SERIES
15. Master Reset – If things are not going
well, for example you are unable to
communicate with the unit, press and
hold down this button for more than
3 seconds. This will reset the inter-
nal Ethernet settings and other odd
things, and hopefully lead you along
the pathway to Ethernet communi-
cations once again. Warning: Do not
do this while turning on the power
switch, because all ash memory will
be erased, and the milk in your fridge
will go bad. In this case you will have
inquire from our ne lads in technical
support about the latest rmware le.
16. Dante Port – This port allows connec-
tion to the optional Dante card via
CAT5.
17. Ethernet LAN Port –This standard
port allows the unit to be connected to
a 10BaseT network via CAT5 cabling.
the unit can then be controlled using
its internal web server, accessible
through standard and popular (and
some unpopular) web browsers. No
external software is required to run
the unit. See the section on Internet
Connectivity and Control for detailed
information.
Speaker Connections
Establish a standard connection color
code and stick with it. One conductor of
the speaker wire is normally marked by
a dierent color (silver versus copper) or
there is a ribbing on one side. Typically this
marked conductor is used for the positive
(+) speaker leads. Some wires have pos-
itive and negative printed right onto the
wire jacket.
Match the polarity markings on the unit
with the polarity markings on your
speakers. If the wiring is incorrect then the
speakers will be out-of-phase, with a
noticeable decrease in the bass response
and less than goodly-sounding.
Almost Done With The Rear Panel
CM2
CM3
CM4
Mode Switch
Set the mode switch per channel to be
Mode A for running 70V speakers, and
Mode B for running low impedance
speakers.
Bridged Mono Speaker Connection:
In this mode, the input signals are
combined in mono, and the power
from two channels is combined to
drive a single, more powerful, speaker.
Each bridged channel must be set to
Mode B.
The speaker impedance should be
4 Ohms minimum in bridged mono
operation.
To set the zone output to be in mono,
use the unit’s web server and click on
the Mono box for this zone. Each zone
menu can be expanded and the Mono/
Stereo button will be seen.

18
Speaker and Wiring Impedance
Speaker and Wiring Impedance
Wire Gauge Run Length
25’ 50’ 100’ 250’ 500’
24 GA 1.3Ω 2.6Ω 5.1Ω 12.8Ω 25.7Ω
22 GA 0.8Ω 1.6Ω 3.24Ω 8.1Ω 16.0Ω
20 GA 0.5Ω 1.0Ω 2.0Ω 5.0Ω 10.1Ω
18 GA 0.3Ω 0.6Ω 1.28Ω 3.2Ω 6.4Ω
16 GA 0.2Ω 0.4Ω 0.8Ω 2.0Ω 4.0Ω
14 GA 0.1Ω 0.25Ω 0.5Ω 1.26Ω 2.5Ω
12 GA 0.08Ω 0.16Ω 0.32Ω 0.8Ω 1.6Ω
Speaker Wire Resistance:
Wire Gauge versus Run Length
ues in portions of their frequency range,
and speakers that are rated at unusual
impedances, for example 3.5 Ohms. The
unit is tolerant of lower impedance loads,
however, all good designs use some mar-
gin of error.
Your choice of speaker wire gauge and the
length of the runs, also aects the speaker
impedance load presented to the ampli-
ers. As you can see in this table, even fairly
short speaker runs can have signicant
resistance if you use a smaller wire gauge.
This can be a benet if you are paralleling
lots of speakers.The wire itself acts as
an impedance limiter, since the amplier
cannot see a speaker load lower than the
resistance of the wire. The downside of
this wire resistance is that you waste some
part of the total power available to the
speakers.
Speakers, like other resistors, when wired
in parallel “show” lower values than the
individual components. Here are two
examples for calculating speakers wired in
parallel:
Calculating Impedance
For three 8 Ohm speakers wired in
parallel (pluses connected to pluses)
the impedance is 1/8 + 1/8 + 1/8 = 3/8
Then take the inverse or 8/3 = 2.66 Ω
For two 8 Ohm speakers wired in
parallel (pluses connected to pluses)
the impedance is 1/8 + 1/8 = 2/8
Then take the inverse or 8/2 = 4 Ω
Often the real world is more complicated
than theory, and for speakers this is the
case. An eight Ohm speaker is not eight
Ohms at all frequencies. Plus passive
crossover networks add their own chang-
ing conditions. Be aware of speakers that
have signicant dips from “nominal” val-

19
Installation Manual
CM2-750, CM3-750, CM4-750
CM SERIES
12 Volt Trigger Ins and Outs
12 Volt Trigger Ins and Outs
The unit has four ways you can bring it
from standby to turn on and be ready to
serve. In addition, you can use the triggers
from the unit to turn on more units or oth-
er components as well. All this exibility
can be a little daunting, so the table below
should make it a tad clearer:
Method How Triggered
1 Ethernet
2Jumped Phoenix
connector
3 Contactclosureon
Phoenix connector
4
12 volt input on Phoenix
connector
5Zone Triggers
The following details apply if you do not
want to use the Ethernet web server to
turn on the unit.
Main Trigger 3-pin connector
To remotely turn on the unit, use either
a contact closure between the Trigger
Input and the +12V output, or an external
+12V trigger between the Trigger In and
GND terminals. The +12V output is not
designed to power other pieces of equip-
ment or jump start your car.
Pinout:
GND Ground
+12V Output
+12V Trigger Input
Power Up Process: When a +3 to +12V
signal is sensed at the trigger input of the
3-pin connector, all the zones will be held
in standby for about 2 seconds until the
power supplies have fully charged and
performed their self-tests. During this
short process, the front panel Power and
Protection LEDs will be red. Once this is
complete, the Power LED will turn blue
and the Protection LED will turn o.
Power Down Process: As soon as a
Zero Volt signal is sensed at the master
trigger inputs, all zones will be muted and
placed in standby. The front panel Power
LED will remain on, as the main power
supplies will be still energized.
If the master trigger Inputs remain at
Zero Volts for 2 seconds, the main power
supplies will shut o; the front panel Pow-
er LED will change from blue to red. The
Protection LED will ash red once during
the power-down process.
The trigger input is biased towards
ground. This keeps the unit in standby
when nothing is connected.
If you are not using master triggering or
the Ethernet connection, then you must
install a short wire link from the +12V
output to the trigger input. To put the unit
into standby, remove the link.
To trigger ON with a contact closure:
Connect the contact closure between
+12V and Trigger Input
To trigger OFF with a contact closure:
Connect a 1 kΩ resistor between +12V
and Trigger Input
Connect the contact closure between
Trigger Input and GND

20
To use an external 12V trigger:
Connect the external ground to the
unit’s Trigger GND
Connect an external +12V output volt-
age to the unit’s Trigger Input
To use Zone triggers:
Zones can be turned on with +12 VDC
and ground connections. The Zone
turn-on is sensitive down to +4 VDC.
12 Volt Trigger (continued)