Next PROAUDIO M804DSP User manual

INSTALLATION GUIDE / USER MANUAL
M804DSP

Technical and Safety Notices
Please read the following important technical, safety
and environmental notices before installing and using
your amplier.
Technical Notices
All reasonable design and engineering steps have been taken
to ensure that these ampliers always perform satisfactorily
in their intended application and environment and will provide
appropriate levels of support to ensure that all reasonable
customer needs and expectations are met. Such support
however is contingent on the following provisions.
1. These ampliers are Class-I products and should be installed
with a mains cable including the required earth connection to
comply with the Safety Class-I.
2. These ampliers should always be installed by competent
and qualied personnel. Amplier damage or failure caused
by installation or operational errors may invalidate support,
warranty or guarantees of performance.
3. These ampliers are not suitable for use in locations where
they may be accessible to minors.
4. These ampliers are intended to be used specically for the
amplication of audio signals and for connection to moving-coil
loudspeaker systems. Use of these ampliers for amplication
of signals outside the audio band (20Hz to 20kHz) or to drive
transducers other than moving-coil loudspeakers may invalidate
support, warranty or guarantees of performance.
5. These ampliers should only be used within professionally
installed and congured audio systems comprising input
and output ancillary equipments that is known to be of an
appropriate level of performance and in good operating
condition. Any damage to, or unsatisfactory performance from,
these ampliers caused by inadequate or failed input or output
ancillaries may invalidate support, warranty or guarantees of
performance.
6. These ampliers are intended to be installed and operated
indoor in a controlled environment (pollution degree, PD2)
within an ambient temperature range of 0°C to 40°C. These
ampliers are not intended for use above 2000 meters above sea
level. Ampliers installed or operated in environments outside
these limits may invalidate support, warranty or guarantees of
performance.
7. Specic warranty terms are the responsibility of the amplier
re-seller.
Safety and Environmental Notices
Note: The intent of the lightning ash with arrowhead symbol in a
triangle is to alert the user to the presence of uninsulated “dangerous”
voltage within the product’s enclosure that may be of sufcient
magnitude to constitute a risk of electric shock to humans.
Note: The intent of the exclamation point within an equilateral
triangle is to alert the user to the presence of important safety, and
operating and maintenance instructions in this manual.
WARNING! TO PREVENT FIRE OR ELECTRIC SHOCK,
DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR
MOISTURE.
Ambient Temperature Note: If this equipment is
operated in a conned or multiple rack installation, the
internal ambient operating temperature may exceed
the external ambient temperature. It is
important to ensure in these circumstances
that the published maximum operating
temperature for the equipment is not
exceeded.
Reduced Air Flow: Ensure that rack or
other closed installation does not restrict
the cooling airow required for safe and
reliable operation of the equipment.

Technical and Safety Notices
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. Do not submerge the equipment in water or liquids.
7. Do not use any aerosol spray, cleaner, disinfectant or
fumigant on, near or into the equipment.
8. Clean only with a dry cloth.
9. Do not block any ventilation opening. Install in accordance
with the manufacturer’s instructions.
10. Do not install near any heat sources such as radiators, heat
registers, stoves, or other apparatus (including ampliers)
that produce heat.
11. To reduce the risk of electrical shock, the power cord shall
be connected to a mains socket outlet with a protective
earthing connection.
12. 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 a third grounding prong. The wide blade or the
third prong are provided for your safety. If the provided
plug does not t into your outlet, consult an electrician for
replacement of the obsolete outlet.
13. Protect the power cord from being walked on or pinched
particularly at plugs, convenience receptacles, and the point
where they exit from the apparatus.
14. Do not unplug the unit by pulling on the cord, use the plug.
15. Only use attachments/accessories specied by the
manufacturer.
16. Unplug this apparatus during lightning storms or when
unused for long periods of time.
17. 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 apparatus has been exposed to rain or moisture, does
not operate normally, or has been dropped.
18. The appliance coupler, or the AC Mains plug, is the AC mains
disconnect device and shall remain readily accessible after
installation.
19. Adhere to all applicable, local codes.
20. Consult a licensed, professional engineer when any doubt or
questions arise regarding a physical equipment installation.
Environmental Statement
This product complies with international
directives, including but not limited to the
Restriction of Hazardous Substances (RoHS)
in electrical and electronic equipment, the
Registration, Evaluation, Authorization and
restriction of Chemicals (REACH) and the
disposal of Waste Electrical and Electronic Equipment (WEEE).
Consult your local waste disposal authority for guidance on how
properly to recycle or dispose of this product.

Introduction and Overview
1. Introduction
M804DSP power ampliers have been designed to
provide congurable, consistent and reliable high
performance audio power amplication for residential,
commercial and entertainment applications.
This manual covers the features, installation and
functions of the M804DSP IP500.2, IP800.2, IP500.4
and IP800.4 models. Please read the manual fully
before installing and using an amplier. If you have any
questions regarding amplier conguration, installation
or operation please contact the appropriate customer
support portal.
Following this introduction, the manual is divided into sections
covering the following topics:
• 2. Overview
• 3. Carton Contents
• 4. Installation
• 5. Conguration
• 6. Connections
• 7. Operation
• 8. Specications
2. Amplier Overview
M804DSP ampliers are a full rack width, 2U format power
ampliers that can drive both conventional low impedance (Lo-Z,
4Ω to 16Ω) loudspeakers and high impedance (Hi-Z, 70V/100V)
transformer coupled loudspeakers. They provide four analog
inputs, one stereo S/PDIF digital input, and either two or four
outputs (Lo-Z mode), or one or two outputs (Hi-Z or Lo-Z BTL
mode). M804DSP amplier model output channel counts and
power outputs are as follows:
M804DSP
Mode Channels Max Rated Output per Channel
Lo-Z Four 750 Watts
Lo-Z (BTL) Two 1500 Watts
Hi-Z Two 1500 Watts
Note: In Lo-Z BTL (bridge-tied load) mode, two amplier output
channels are combined to create a single, double power output
channel. BTL mode can be engaged via the amplier Output Mode
conguration setup menu described in Section 5 of this manual.
2.1 Connections and Power Switching
M804DSP signal input and output connections are accomplished
via RCA Phono and Euroblock style connectors. A GPIO (General
Purpose In/Out) Euroblock connector enables some amplier
functions to be controlled externally, and wireless or RJ45
socket Ethernet network connection options are also provided.
Cable connectors and connections are described and illustrated
in Section 6 of this manual
M804DSP ampliers incorporate a front panel mounted power
button. Press the button once to switch the amplier on or off.
Amplier power management behaviour can be congured via
the Control web app Settings Menu described in Section 5 of
this manual.

Introduction and Overview
2.2 Network Features
M804DSP ampliers are TCP/IP network connected devices
that require a wired or wireless network connection to access
their conguration menus. The conguration menus are
accessed via the Control Web App interface and cover Input,
Zone, Output and General Settings functions. The Control
web app conguration menus are described in Section 5 of this
manual.
2.3 Firmware
This manual describes the features, functions and user interface
of M804DSP ampliers running Firmware Version 1.4.0.
It is strongly recommended that the rmware version installed
in the amplier in use is checked initially, and regularly
thereafter. If updated rmware is available, the amplier
should be updated as a priority.
The rmware installed in the amplier can be identied and
updated by selecting the Device option in the Control web app
Settings Menu. Firmware versions can be checked, and rmware
downloaded, from the website:
https://www.nextaudiogroup.com/en/product/m804-dsp
3. Carton Contents
M804DSP ampliers are shipped in a cardboard carton
containing the amplier unit, a mains cable appropriate for the
sales territory, an accessory pack, and a document pack. The full
contents is listed below.
• Amplier unit
• Rack mount ears (tted)
• Mains power cable
• Input connector x 2
• GPIO socket connector
• Output connector x 1 or 2
• Adhesive rubber feet x 4
• Document pack

Installation
Diagram 4A
M804DSP ampli er dimensions.
(Shaded area de nes ventilation space.)
440 mm
17.3 in
332 mm
13.1 in
4. Installation
4.1 Ampli er Location
M804DSP ampli ers are shipped with rack “ears” attached and
are primarily intended for standard (19 inch)equipment rack
installation. If not to be installed in an equipment rack, M804DSP
ampli ers can be placed free-standing on a  at surface. Adhesive
rubber feet are supplied for this purpose.
It is important that any installation provides space for air ow
through the ventilation apertures at the front and rear of the
ampli er. This is illustrated in Diagram 4A.
88 mm
3.5 in

Conguration
5. Conguration
Before making input, output and GPIO connections,
an initial M804DSP amplier conguration should
be established. It is particularly important that the
amplier output format is congured appropriately for
the speakers that are to be connected.
Conguration requires that M804DSP ampliers are
connected to mains power, switched on and connected
to network services. These connections are described in
the following two sections.
5.1 Mains Power Connection
M804DSP ampliers incorporate a power factor corrected
power supply and can be used with mains input voltage from
100V AC to 240V AC, 50/60Hz. Use the mains cable supplied
with the amplier and connect it to a mains supply.
Press the front panel power button to switch on the amplier.
After a short delay the front panel Status indicator will illuminate
green.
5.2 Network Services
M804DSP ampliers are congured via the Control
Web App interface. Before the Web App conguration
menus can be accessed, M804DSP ampliers must be
connected to the same TCP/IP network as the computer
or mobile device that is to be used for conguration.
5.2.1 Wired (Ethernet) Network Connection
To connect a M804DSP amplier to a TCP/IP network using a
wired connection (Ethernet) follow the steps below.
1. Use an Ethernet cable to connect the M804DSP amplier
rear panel Network Control socket to a free socket on a network
router or switch, or directly to an Ethernet equipped laptop or
desktop computer.
2. Connect the M804DSP amplier to mains power using the
supplied mains cable. Wait for the front panel Network indicator
to illuminate green to indicate that the amplier has network
connectivity.
3. The M804DSP amplier default LAN IP address is
192.168.64.100. Congure the laptop or desktop computer
for a xed IP address in the same IP range; eg. 192.168.64.10,
with Subnet mask of 255.255.255.0 (or prex 24) and set the
Gateway to 192.168.64.1.
4. Open a laptop or desktop web browser and enter the address
http://192.168.64.100. The Control Web App interface will
open to enable amplier conguration as required.
Note: M804DSP ampliers can be congured to use DHCP for
network connection if required. However, if a M804DSP amplier
using DHCP is power cycled, it is possible that the TCP/IP network
router will assign it a different IP address, leaving its conguration
page inaccessible via the previous address. If this occurs, a network
scanning app can be used to identify the new IP address. DHCP and
Fixed IP address option settings can be found in the Settings Tab
menu described in Section 5.3.
5.2.2 Wireless (WiFi) Network Connection
To connect a M804DSP amplier to a TCP/IP network using a
wireless connection (WiFi) follow the steps below.
1. With the M804DSP amplier connected to mains power, wait
for the front panel WiFi indicator to illuminate green.
2. Use a mobile, laptop or desktop device to search for available
WiFi networks. Connect to, NEXT-proaudio M804DSP (product
serial number)’ using the password, ‘password’. The amplier
serial number can be found on its rear panel.
3. Open a computer or mobile device web browser and enter the
IP address: 192.168.4.1. The Control Web App interface will
open to enable amplier conguration as required.
4. Select the Web App Settings Tab followed by WiFi > WiFi
Mode > Client to congure the amplier to connect to the
required WiFI network. The WiFi network name and password
will be required.
It is strongly recommended that the M804DSP amplier
Access Point WiFi password is changed following initial
wireless connection.

Conguration
5.3.1 Input Tab
The Input Tab provides the following conguration parameters
for each amplier input channel:
• Input name
• Mono/Stereo selection
• Input sensitivity
• High-pass lter
• Gain trim
• Five band equalisation
The Input Tab also enables input signals to be mixed and routed
to specic amplier zones. The mix function enables any
amplier input, including stereo or split mono S/PDIF inputs,
to be grouped with any other input or inputs to create multiple
predened mixes.
Note: The number of individual mixes possible is equal to the number
of amplier analogue inputs.
Note: Mix inputs are muted by default with their level adjustment
sliders set to zero.
Mix operations take place following high-pass lter, input
equalisation and mono/stereo selection.
Diagram 5A
Conguration Dashboard display
Diagram 5B
Input Tab display
(two inputs only shown)
Input name - type to edit
Select mono or stereo
Select input sensitivity option
Adjust input gain
Open EQ window
Adjust zone volume
Adjust zone volume
Note: When adjusting input gain, the input level display should
remain green. If it displays red, the input gain should be reduced.
5.3 Conguration Menus
Opening a web browser that is network connected to a
M804DSP amplier initially displays the M804DSP Control
Web App Dashboard illustrated in Diagram 5A. The Dashboard
is the ‘home’ page from which all other conguration options can
be accessed.
The Dashboard displays the amplier status, output zones and
the conguration menu tabs. It also enables immediate access
to zone volume control The functions available under each
conguration menu tab are described in the following sections.
Select input type

Conguration
Diagram 5C
Input EQ display
Diagram 5D
Input Mix display
A pink noise or sine wave audio signal generator, appropriate for
audio system testing and set up, can also be enabled, disabled,
and adjusted for gain and frequency via the Input Tab. Diagrams
5B, 5C and 5D illustrate the Input Tab, Input EQ and Input Mix
displays respectively.
5.3.2 Zone Tab
The Zone Tab enables installation zones to be dened and named,
and provides access to further sub-menus. Zones might be bar or
restaurant areas for example, or different rooms in a home. For
all Zone Tab menus, the installation zone under conguration is
selected by highlighting one of the zone identiers (A, B, C or D)
at the top of the display. Diagram 5E and 5F illustrates the Zone
Tab and Source menu displays.
• The Source menu enables inputs to be assigned to zones and
Input Priority or Input Ducking to be congured. The Input
Priority function enables an alternative input to replace
and mute the input primarily routed to the zone under
conguration when the alternative input exceeds a preset
level.
The Input Ducking function enables an alternative input to
replace and attenuate the input primarily routed to the zone
under conguration when the alternative input exceeds a preset
level.
Zone name - type to edit
Select zone
Select mix function
Select mono or stereo
Select zone input
Congure zone volume options
Congure zone restrictions
Congure zone compressor
Adjust zone volume
Diagram 5E
Zone Tab display
Select and adjust required EQ stages
Mix name - type to edit
Adjust mix input level

Conguration
Note: Input Priority and Input Ducking parameters can be either set
to default values or their Threshold, Attack, Hold and Release values
set as required. Input Priority can also be set to ignore the volume
level set for the specied zone and take a specic override volume.
• The Volume menu allows minimum and maximum zone
volume limits to be set, and enables external GPIO volume
control to be applied to individual zones. The GPIO
conguration menu can be found under the Settings Tab,
and notes on connecting an external volume control via the
GPIO interface can be found in Section 5.5 of this manual.
Note: If an amplier is controlled via a third-party control system API,
volume level limits set via the Input Tab will not apply.
• The Restrictions menu enables zone inputs or input mixes to
be restricted from routing to particular zones.
Note: Routing restrictions cannot be applied to priority zone inputs.
Note: If an amplier is controlled via a third-party control system API,
input routing restrictions set via the Input Tab will not apply.
• The Compressor option enables default or custom signal
compression to be applied to individual zones.
Note: Compression can be useful to reduce the volume difference
between loud and quiet audio material. The lower the compression
threshold is set, the more the difference between loud and soft will
be reduced. The overall zone volume may need to be increased
when compression is used. The default compression parameters are
appropriate for most installations.
5.3.3 Output Tab
The Output Tab enables amplier outputs to be named, linked
to zones, and provides access to Delay, Equalizer and Speaker
Preset menus. Diagram 5G illustrates the Output Tab display.
For all Output Tab menus, the amplier output under
conguration is selected by highlighting one of the output
identiers (1, 2, 3 or 4) at the top of the display.
Note: The number of individual outputs available for conguration
will depend on the M804DSP amplier model and the input, zone
and output mode conguration.
• The Routing menu enables zones to be assigned to amplier
outputs.
Note: Routing for zones specied as stereo will automatically offer
three output options: left channel, right channel or summed mono.
The summed mono signal can potentially be used to drive a mono
subwoofer.
• The Delay menu enables delay to be applied to individual
amplier outputs.
Output name - type to edit
Select output
Enable and congure output delay if required
Dene output routing
Enable and congure output EQ if required
Congure and manage speaker presets
Diagram 5G
Output Tab display
Diagram 5F
Zone Source menu display
Select zone

Conguration
• The Equalizer menu enables parametric equalization to be
applied to individual amplier outputs. Equalizer settings
congured for one amplier output can be copied and
applied to other outputs.
• The Speaker Preset menu enables a set of speaker
parameters to be adjusted, and preset congurations to be
created, exported, imported or cleared.
Speaker Presets can be simply applied to the selected
amplier output or imported, chosen from a library, exported
or cleared. The preset congurations can include any or all of
the parameters described in Section 5.3.4 and can be locked
to prevent inadvertent modication. Diagrams 5H to 5K
illustrate the application of speaker presets.
Speaker Preset data provided by third parties for use with
specic speakers can be imported and applied to amplier
outputs. To import speaker preset parameters follow the
steps described below and illustrated in the diagrams.
1. Select either the IMPORT PRESET FROM LIBRARY
or SELECT PRESET FROM FILE option from the
Speaker Preset menu. If no import option is visible,
select CLEAR to delete any existing speaker preset
data.
Note: The SELECT PRESET FROM LIBRARY option will be unavailable
if no speaker preset libraries have been created. Speaker preset library
creation and management is described in Section 5.3.5.
2. Select the appropriate ‘.zcp’ format speaker preset
data le to import from either a Library or a
computer folder. The preset data will be applied
to the selected amplier output as soon as the le
import is complete.
3. If the Speaker Preset data requires modication it
can be customized by selecting the CUSTOMIZE
PRESET option.
Note: If an imported Speaker Preset data le includes locked
parameters, they will be unavailable for modication.
5.3.4 Speaker Preset Menu Parameters
• The Crossover & Gain preset menu enables high or low-
pass crossover lters and gain adjustment to be applied to
individual amplier outputs.
• The Speaker EQ preset menu enables parametric
equalization to be applied to individual amplier outputs.
• The FIR preset menu enables FIR (Finite Impulse Response)
Select to congure
Select to congure
Select to congure
Select to congure
Select to congure
Select to congure
Select to congure
Select to congure
Diagram 5H
Speaker Preset Parameters
Diagram 5I
Speaker Preset import le selection
Select output

Conguration
Diagram 5J
Speaker Preset applied
Diagram 5K
Speaker Preset parameter adjustment
based equalization lter coefcients generated by external
speaker measurement software to be imported and applied
to individual amplier outputs.
Note: FIR coefcient les in either .csv or .txt format can be imported.
• The Driver Alignment preset menu enables delay to be
applied to individual amplier outputs.
• The Polarity preset menu enables the polarity of individual
amplier outputs to be reversed.
• The Limiter preset menu enables signal limiting to be
engaged or bypassed on individual amplier outputs. Clip
limiting, Peak limiting and RMS limiting can be individually
or collectively engaged. The Clip limiting function offers
Fast and Normal response time options. The Peak limiting
function can be set to either Automatic or Manual parameter
values. The RMS Limiter has default parameter values that
can be adjusted but has no automatic option.
Note: It is strongly advised that if an amplier is driving low impedance
loads (<4Ω) the Clip Limiter should be engaged and set to Fast.
Note: In automatic mode, the peak limiter parameters adjust
automatically in response to Crossover & Gain high-pass lter
settings.
• The Output Mode preset menu enables individual amplier
outputs to be switched off or congured for Lo-Z or
Hi-Z modes. In Hi-Z modes, a high-pass lter can also be
congured and applied to the output. The number of outputs
available will depend on the amplier model, input setup and
zone setup. For example, a two output amplier will have
two outputs available if Lo-Z mode is selected but only one
output available if Hi-Z mode is selected.
Note:: Use of a high-pass lter with Hi-Z mode loudspeakers is useful
to avoid the possibility of distortion caused by low frequency line
transformer saturation. Begin with the default lter setting of 70Hz.
If low frequency distortion is still audible, increase the frequency
setting one step at a time until the distortion is no longer audible.
5.3.5 Settings Tab
The Settings Tab enables miscellaneous amplier settings to be
congured and installation data to be recorded.

Conguration
Diagram 5L
Settings Tab menu
Diagram 5M
The External Devices display
External device - tap to congure
The Settings Tab provides access to further sub-menus. Diagram
5L illustrates the Settings Tab.
• The System Information menu provides text elds for the
recording of installation data.
• The Device menu records amplier specic information
such as the model number and rmware version. A rmware
update routine and identier button can also be found under
the Device menu.
• The External Devices menu enables control panels to be
paired with an amplier and congured. Each individual
amplier zone to be controlled will require its own control
device. Diagram 5M illustrates the External Devices display.
• The Backup & Restore menu enables amplier conguration
data to be downloaded to an external archive, and enables
previously saved conguration les to be uploaded and
adopted by the currently connected amplier.
• The Speaker Library menu enables management of speaker
preset libraries. Existing libraries of speaker preset les (.zcl)
can be created or imported, and existing libraries edited
or fully deleted. Diagram 5N illustrates the creation and

management of speaker preset libraries.
• The Security menu enables a password to be set in order to
protect against unauthorised access to the amplier Control
Web App. Password protection is particularly important
when an amplier is connected to a wired network as the
a WiFi password is no longer required to gain access to
Control Web App.
Note: It is recommended that a Control Web App password is different
from that required to gain access to the amplier via WiFi.
• The Power Management menu enables various automatic
switch-on options to be engaged. The Power Management
menu also offers timed Standby and Mute functions.
• The Output Routing menu enables specied inputs or zones
to be routed to the amplier S/PDIF outputs. The output
level can also be adjusted.
Any zone or input can be routed to either digital output,
including inputs not actively assigned to a zone. Primary
or priority input status is immaterial. The specied input is
always routed to the specied output to be available for use
by downstream devices.
Note: The digital output function is especially useful when ampliers
are to be daisy chained and a specic input; a central paging mic, for
example, is required to be routed to multiple ampliers..
• The GPIO menu enables conguration of the multi-purpose
GPIO interface pins.
• The LAN menu enables conguration and reset of the wired
network options and parameters.
• The WiFi menu enables conguration and reset of the
wireless network options and parameters.
Conguration
Diagram 5N
Speaker Library Creation and Management
Library name - type to edit
Library version - type to edit
Import preset data (.zcp) to library
Creat new library
Rename library
Delete library

Conguration
Diagram 5O
Signal Flow Schematic
(four output amplier)
5.4 Setup and Signal Routing
Thanks to their network based conguration features,
M804DSP ampliers offer considerable versatility in terms of
sources, signal routing, installation zones and output modes.
Inputs can be freely assigned to installation zones, and those
zones assigned freely to the available amplier outputs in either
Lo-Z or Hi-Z modes.
This versatility enables, for example, one amplier
simultaneously to drive both Lo-Z and Hi-Z speakers, or for
different inputs to be routed to different output zones.
The following paragraphs describe and illustrate the
recommended procedure for conguring input, zone and output
routing. A general signal ow schematic is also illustrated in
Diagram 5O.

Conguration
5.4.1 Input Setup
Open the conguration Dashboard and select the Input Tab. The
Input Tab is shown in Diagram 5B.
• To edit default input names simply select and type in the
Input Name eld.
• Dene a mono or stereo input by selecting the appropriate
option. Dening a stereo input will reduce the total number
of discrete inputs available.
• Select an input sensitivity option from the drop-down menu:
+14dB, +4dB, -10dB and ‘microphone’ options are available.
Generally, the +14dB or +4dB options are appropriate
for ‘professional audio’ source hardware with balanced
outputs, while the -10dB option is more appropriate for
‘consumer audio’ source hardware with unbalanced outputs.
The ‘microphone’ option provides the signicantly greater
sensitivity required for microphones.
Note: Only dynamic microphones are suitable for connection.
Phantom power for condenser microphones is not provided.
• If necessary, adjust the input gain using the slider or up/down
icons. Gain adjustment is intended to be used for ne output
level adjustment following initial use.
5.4.2 Zone Setup & Routing
Open the conguration Dashboard and select the Zone Tab. The
Zone Tab is shown in Diagram 5E.
• Select the zone to be congured. The number of zones
available and their channel format (stereo or mono) will
depend on the amplier model, input setup and output
mode (Lo-Z or Hi-Z). For example, a two output amplier
can have the following zone congurations:
• 1 x stereo Lo-Z zone
• 2 x mono Lo-Z zones
• 1 x mono Hi-Z zone
• A four output amplier can have the following zones
congured:
• 2 x stereo Lo-Z zones
• 4 x mono Lo-Z zones
• 2 x mono Hi-Z zone
• 1 x mono Hi-Z zone + 1 x stereo Lo-Z zone
• 1 x mono Hi-Z zone + 2 x mono Lo-Z zones
Note: When congured in Hi-Z mode M804DSP ampliers operate
in ‘bridged’ mode where the output of two channels is combined. This
means that the number of output channels available in Hi-Z mode is
half that available in Lo-Z mode .
Note: Mono signals might be mono at source, created though
combining the left and right channels of a stereo signal (summed
mono) or treating the left and right channels of a stereo signal
independently (split mono).
• Name zones by typing in the Zone Name eld.
• Adjust the zone volume if required by using the slider.
• Dene a mono or stereo zone by selecting the appropriate
option. Dening a stereo zone will reduce the total number
of further zones available.
• Specify an input for the zone by selecting from the drop-
down menu. Selecting a stereo input for a mono zone will
automatically sum the stereo channels to mono.

Conguration
5.5 GPIO Setup and Connection
M804DSP ampliers provide a GPIO socket that enables
remote control of volume, standby, mute and trigger functions.
The GPIO connector pin functions are described in the GPIO
Settings menu illustrated in Diagram 5P. The connection of
GPIO based remote volume control and standby/mute are
illustrated in Diagram 5Q and Diagram 5R respectively.
Note: The GPIO connector must not be used for any unintended
purpose. Amplier damage may result from incorrect use of
GPIO.
Note: Shielded cable must be used when connecting standby
switches and potentiometers via GPIO.
Note: GPIO Pin 8 has a low output impedance and is able to
supply a maximum current of 10mA.
Note: GPIO Pin 1 and Pin 3 both offer ground connections:
Pin 1 is connected directly to the amplier chassis.
Pin 3 is connected to the chassis via a 220 Ohm resistor.
The ‘soft ground’ connection of Pin 3 is potentially useful for
managing ground loops that may cause audible hum.
Diagram 5P
GPIO Settings Menu
Diagram 5Q
Potentiometer connections for remote vol-
ume control via GPIO.
Note: Diagram 6D illustrates
use of the GPIO connector.
Diagram 5R
Connections for remote
standby/mute switch via GPIO.
Note: Diagram 6D illustrates
use of the GPIO connector.
Ground
+3V3
Expansion
Port
Ground
Standby/Mute
Expansion
Port
Potentiometer
(>10kΩ)
Connect Wiper to
Pin 4, 5, 6 or 7. Switch open or closed
toggles Standby or Mute
depending on options
selected in the GPIO
Settings Menu

Connections
6. Connections
M804DSP amplier rear panel connections are
illustrated in Diagrams 6A.
6.1 Mains Power Connection
M804DSP ampliers incorporate a power factor corrected
universal power supply and can be used with mains input voltage
from 100V AC to 240V AC, 50/60Hz. Use the mains cable
supplied with the amplier.
M804DSP ampliers incorporate a front panel mounted power
button. Press the button once to switch the amplier on or off.
Ensure that all signal, GPIO and output connections are made
before switching on the amplier.
6.2 Input Connection
M804DSP amplier provide four balanced or unbalanced
analog audio inputs and a stereo S/PDIF digital audio input. Any
input channel can be routed to any output channel. Input routing
options can be congured via the Control Web App Input Tab.
See Section 5 of this manual.
Analog Inputs
M804DSP analog inputs are of line level format with a default
input sensitivity of +4dBu (full output voltage swing/sensitivity)
in all output modes. Depending on the selected sensitivity,
the inputs can handle up to +24dBu without clipping. Input
sensitivity options can be set via the Control Web App Input
Ta b . See Section 5 of this manual.
Balanced input connections to the ampliers are made via male
‘Euro Block’ connectors. Connecting cables to the supplied
female input connectors is illustrated in Diagram 6B.
Unbalanced input connections to the ampliers are made via
RCA phono sockets connected in parallel with the balanced
inputs.
Diagram 6A
M804DSP rear panel connections.
Note: Two output amplier model connection sockets differ only in
the deletion of channel 3 and channel 4 output connectors.
Digital Outputs
M804DSP Connect S/PDIF stereo digital audio output
connections are made via a single RCA Phono socket. The S/
PDIF output signal can be routed from any input or zone and
is intended to be used for daisy-chaining M804DSP Connect
ampliers.
Note: See the Output Routing paragraphs of Section 5.3.3 for more
information on Digital Output conguration.
Note: 75Ω RCA Phono cables specically intended for digital audio
should always be used for S/PDIF connections. Standard Phono
cables can be used but may not result in optimal performance.
Note: The S/PDIF output level is by default set at -10dB to reduce the
possibility of downstream input clipping.
6.3 Output Connections
Output connections from the ampliers are achieved via male
‘Euro Block’ connectors. Ensure that speaker connection
polarity is correct throughout the installation:
In the case of Lo-Z speaker connections, positive (+) amplier
terminals should always be connected to positive speaker
terminals and negative (–) amplier terminals always connected
to negative speaker terminals.
In the case of Hi-Z speaker connections, the two speaker cable
conductors should be connected between the positive (+)
terminal of Output 1 and the negative terminal (-) of Output 2,
and likewise for Outputs 3 and 4.
Output mode options (Lo-Z or Hi-Z) can be congured via the
Control Web App Input Tab. See Section 5 of this manual.
Connecting cables to the supplied female output connector is
illustrated in Diagram 6C.
Expansion
Port

Cable Gauge Table
Lo-Z installations, 0.5dB attenuation. 2 Ω, 4 Ω & 8 Ω loads
Cable Gauge Table
70V Hi-Z installations, 1.0dB attenuation
20 speakers evenly distributed
Cable Gauge Table
100V Hi-Z installations, 1.0dB attenuation
20 speakers evenly distributed
Cable Cross
Section
(mm2)
Cable Gauge
(AWG)
Max Cable
Length
(Metres, 2 Ω
load)
Max Cable
Length
(Metres, 4 Ω
load)
Max Cable
Length
(Metres, 8 Ω
load)
0.75 ≈18 N/A 5 10
1.5 ≈16 5 10 20
2.5 ≈14 8 17 35
4.0 ≈12 14 28 55
Cable Cross
Section
(mm2)
Cable Gauge
(AWG)
Max Cable Length
(Metres),
(1000 W/channel)
Max Cable Length
(Metres),
(1200 W/channel)
0.75 ≈18 25 20
1.5 ≈16 50 40
2.0 ≈14 80 60
3.5 ≈12 125 100
Cable Cross
Section
(mm2)
Cable Gauge
(AWG)
Max Cable Length
(Metres),
(1000 W/channel)
Max Cable Length
(Metres),
(1500 W/channel)
0.75 ≈18 50 30
1.5 ≈16 100 60
2.0 ≈14 160 100
3.5 ≈12 250 160
Connections
6.4 Speaker Cable Gauge
M804DSP speaker connection cable gauge should be
chosen appropriately to reect the type of installation.
The adjacent tables specify the appropriate cable gauge
and maximum cable length for less than 0.5dB cable loss
in Lo-Z mode and less than 1.0dB cable loss in Hi-Z mode.
6.5 GPIO Connections
If any M804DSP GPIO functionality is required,
cables will need to be connected to the supplied GPIO
connector. Connecting cables to the GPIO connector is
illustrated in Diagrams 6D.
6.6 Network Connections
M804DSP ampliers are TCP/IP network connected
devices that are congured via a web page based interface.
Wired (Ethernet) and wireless (WiFi) connection options
are available. Connecting M804DSP ampliers to a TCP/
IP network is described in Section 5 of this manual

Low-Z Mode
Hi-Z/BTL
Modes
5 mm
5 mm
5 mm
Connections
Diagram 6B
Balanced analog input
cable connections.
Diagram 6C
Output cable connections.