PROEL AXIOM DSO26 User manual

SOUND REINFORCEMENT
DSO26
DIGITAL SYSTEM OPTIMIZER
www.proelgroup.com MADE IN EUROPE
USE
R
’
S MANUAL

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DSO26 Quick Reference
Accessing channels: press channel’s GAIN button.
First press accesses that channel’s gain. To scroll
through a channels parameters, use the BACK and NEXT
keys. Second press accesses last viewed parameter.
Third press will drop back to the default screen.
Accessing menus: press the MENU key. Use the BACK
and NEXT keys to select the sub-menu required, and
enter using the ENTER key. This applies to all levels of
menu. ENTER always confirms selections.
The Menus and their Contents
Input Setup Sub-menu: Used for ganging input gain and
base delays.
X-over Sub-menu: Used for storage and recall of
crossovers, including format, output EQ, output delay,
output gain, and limiter settings. Also used for design of
new crossovers.
Security Sub-menu: Used for locking various features of
the units, using a four digit code.
System Sub-menu: Used to view the units status, and
select various global options such as parametric EQ ‘Q’
or bandwidth units, and output meter monitoring point
(pre or post mute).
Notes
The crossover or output settings are stored and recalled
independently (using store/recall a X-Over) from the input
settings (using store/recall input memory).
The output meters show level, in dB, from the limiter
threshold. The input meters show level, in dB, from input
clip.
The high and low-pass filters are defined independently
on each channel.
To access the limiter attack and release parameters,
select ‘Auto Limiter TC’ No, when designing a crossover.
To swap parametric filter units between bandwidth (‘BW’)
and ‘Q’, enter the ‘System sub-menu, select ‘Filter Q or
BW’, and select required readout units.

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CONTENTS
DSO26 QUICK REFERENCE .............................................................................................2
The Menus and their Contents .......................................................................................................................... 2
Notes.................................................................................................................................................................. 2
CONTENTS .........................................................................................................................3
IMPORTANT SAFETY INFORMATION ..............................................................................6
THANKS..............................................................................................................................7
UNPACKING THE DSO26 ..................................................................................................7
INTRODUCTION .................................................................................................................8
Features............................................................................................................................................................. 8
FRONT PANEL FAMILIARISATION...................................................................................9
REAR PANEL CONNECTIONS ........................................................................................10
OPERATING THE DSO26.................................................................................................11
Preliminary Set-up ........................................................................................................................................... 11
DSO26 CONFIGURATIONS .............................................................................................12
Introduction ...................................................................................................................................................... 12
2 x 2 way with Mono Sum................................................................................................................................ 12
2 x 3 way.......................................................................................................................................................... 12
4 way + 2 ......................................................................................................................................................... 14
5 way + 1 ......................................................................................................................................................... 15
6 way................................................................................................................................................................ 16
SCREEN LAYOUTS OVERVIEW .....................................................................................17
AUDIO FUNCTION SCREENS .........................................................................................18
Gain Screen ..................................................................................................................................................... 18
Polarity Screen ................................................................................................................................................ 19
Delay Screen ................................................................................................................................................... 20
High and Low Pass Filter Screens .................................................................................................................. 21
Parametric Equaliser Screen........................................................................................................................... 22
Limiter Screen.................................................................................................................................................. 23

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MENU SELECTION...........................................................................................................24
INPUT SETUP SUB-MENU...............................................................................................25
Gang Inputs ..................................................................................................................................................... 25
X-OVER SUB-MENU.........................................................................................................26
Load a Xover ................................................................................................................................................... 26
Design a Xover ................................................................................................................................................ 26
Store a Xover................................................................................................................................................... 26
Erase a Xover Mem ......................................................................................................................................... 26
SECURITY SUB-MENU ....................................................................................................27
User Specific.................................................................................................................................................... 27
Xover Only ....................................................................................................................................................... 27
Xover + Trim .................................................................................................................................................... 27
Xover + Trim + Mute ........................................................................................................................................ 27
Changes Only .................................................................................................................................................. 27
Changes + View............................................................................................................................................... 27
Changes + Mutes ............................................................................................................................................ 27
EVERYTHING ................................................................................................................................................. 27
Entering the Password to Complete the Locking Operation............................................................................ 28
SYSTEM SUB-MENU........................................................................................................29
System Status.................................................................................................................................................. 29
LCD Contrast ................................................................................................................................................... 29
LED Brightness................................................................................................................................................ 29
Temperature Alarm.......................................................................................................................................... 29
Wake-up Time ................................................................................................................................................. 29
Output Meters .................................................................................................................................................. 29
Filter Q or BW .................................................................................................................................................. 29
Delay Time/Distance........................................................................................................................................ 29
INTERFACE SUB-MENU ..................................................................................................30
Interface Setup ................................................................................................................................................ 30
AES / EBU SUB-MENU.....................................................................................................31
Routing Options ............................................................................................................................................... 31
AES Diagnostics .............................................................................................................................................. 31
AES / EBU Connections .................................................................................................................................. 31
OPERATING NOTES ........................................................................................................32
Operating Level ............................................................................................................................................... 32
Grounding ........................................................................................................................................................ 32

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Crossover Filter Slopes ................................................................................................................................... 32
Time Alignment................................................................................................................................................ 33
Output Limiters ................................................................................................................................................ 34
Setting Accurate Limiter Thresholds................................................................................................................ 35
FACTORY PRESETS........................................................................................................37
EDGE presets.................................................................................................................................................. 37
TFL presets...................................................................................................................................................... 39
Voltage gain of TFL amplifiers......................................................................................................................... 42
SPECIFICATIONS.............................................................................................................43
WARRANTY......................................................................................................................44
OPTIONS AND ACCESSORIES.......................................................................................44
APPENDICES ...................................................................................................................45
Appendix 1: Limiter threshold in dB to Vrms lookup table.............................................................................. 45
Appendix 2: Default X-over settings and names for all formats. ..................................................................... 46
Appendix 3: Equalisation Curves.................................................................................................................... 47

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An example of this equipment has been tested and found to comply with the
following European and international Standards for Electromagnetic
Compatibility and Electrical Safety:
Radiated Emissions (EU): EN55013-1 (1996)
RF Immunity (EU): EN55103-2 (1996) RF Immunity, ESD, Burst Transient, Surge, Dips &
Dwells
Electrical Safety (EU): EN60065 (1993)
Important Safety Information
Do not remove Covers.
No user serviceable parts inside, refer servicing to qualified service personnel.
This equipment must be earthed.
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
DO NOT EXPOSE TO RAIN OR MOISTURE
It should not be necessary to remove any protective earth or signal cable shield
connections.
Do not defeat the 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 wider blade and the third prong are provided for your safety. When
the provided plug does not fit into your outlet, consult an electrician for replacement of the
obsolete outlet.
Only use this equipment with an appropriate mains cord.
In the USA the cord should comply with the requirements contained in the Standard for
Cord Sets and Power Supply Cords, UL 817, be marked VW-1, and have an ampacity
rating not less than the marked rating of the apparatus.

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THANKS
Thank you for choosing the DSO26 for your application. Please spend a little time reading
through this manual, so that you obtain the best possible performance from the unit.
All our products are carefully designed and engineered for cutting-edge performance and
world-class reliability. If you would like further information about this or any other product,
please contact us.
We look forward to hearing from you in the near future.
UNPACKING THE DSO26
After unpacking the unit, please check it carefully for any damage. If any is found,
immediately notify the carrier concerned - you, the consignee, must instigate any claim.
Please retain all packaging in case of future re-shipment.

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INTRODUCTION
The DSO26 is a powerful DSP based audio processor, ideally suited for live sound
applications, where it combines the functions of a multitude of conventional products in a
compact 1U unit. To achieve this, the DSO26 has two inputs and six outputs which can be
configured in five basic crossover modes – 3 x 2 way; 2 x 3 way; 4 way; 5 way; and 6 way.
Each input has a gain control, and variable base delay. Each output has a gain control,
variable delay, high and low pass filters, five bands of fully parametric equalisation, polarity
switching and, additionally, a fully featured limiter.
Multi-part security lock-out is available for all controls.
The DSO26 is also available with optional AES/EBU digital inputs and outputs.
It has been designed for quick, intuitive adjustment through the use of multiple controls to
provide an easy-to-use interface.
Features
 Superb audio quality – carefully optimised double precision signal processing
coupled with a 40-bit internal data path ensures a dynamic range in excess of
110dB. The high sampling rate means minimal filtering providing exceptional sonic
purity.
 A flexible 2-input/6-output multi-mode format caters for any crossover configuration,
regardless of scale.
 A total of 30 parametric equalisation bands are available, each providing +15 to –
30dB of gain at centre frequencies between 20Hz and 20kHz, with a wide range of
‘Q’s available between 0.4 to 128. All parameters feature fine resolution with 1/36
octave frequency steps, 0.1dB gain increments, and 100 ‘Q’ settings. Any
parametric section can also be set to operate as a high or low shelving filter.
 Each output features a high performance limiter, provided with complete control
over attack, release and threshold parameters. To aid set-up, the output meters
show headroom to the limiter threshold, and use time constants that track those of
the limiter to display precise power usage.
 Each output features variable high and low pass filters, with a choice of 12, 18 or
24dB/Octave roll-off, and Butterworth, Bessel or Linkwitz-Riley responses.
Independent control of each high and low pass filter allows asymmetric crossover
bands to be created.
 Delay of up to 650mS may be independently set for each output, with an
exceptionally fine minimum increment of 2.6µS.
 Three velocity-sensitive encoders provide a familiar and intuitive control format with
all filter information displayed simultaneously on a backlit LCD screen.
 AES/EBU Digital input and output interfaces are available as an option.
 Input and output balancing transformers are also available as an option.

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FRONT PANEL FAMILIARISATION
LCD Screen: shows menu options, channel
information, and various parameters as they are
adjusted.
Next Key : moves forwards through the list of available parameters.
Back Key : moves back through the list of available parameters.
Menu Key : activates the main menu. A second press selects the last
menu edited. Selection of different menus may be accomplished using the
Back and Next keys, or by turning the ‘Freq’ encoder.
Enter Key : enters the chosen menu and confirms choices.
Bypass Key : bypasses the currently selected parametric EQ section.
Note that, for safety reasons, the high and low pass filters cannot be bypassed using this
key.
Quit Key : exits the menu.
Encoders : three velocity sensitive controls allow the relative
parameter displayed on the LCD screen to be adjusted.
Gain Keys : one for each input and output, allowing instant access to
the gain screen for the selected channel.
Input Meters : display available headroom below clipping. The yellow
‘-6dB’ LED illuminates at 6dB below the actual clipping point of the input
section. The red ‘Clip’ LED shows digital overflow and can therefore
illuminate independently of the rest of the meter.
Output Meters: display headroom below limiting. The yellow
LED illuminates 3dB below limiting for that channel. The red
LED indicates the onset of limiting.
Mute Keys: mutes the appropriate channel, and illuminates
the associated LED.

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REAR PANEL CONNECTIONS
Power Switch: turns the units mains supply off and on.
Mains Fuse: located in a finger-proof holder adjacent to
the mains inlet. A spare fuse is also located in this holder.
Mains Inlet: connected via a standard IEC socket.
External: RS232 standard via a 9 pin D-type connector, for
connection to a PC, enabling the uploading of new software to
the unit.
Audio In-Out: 3 pin XLR sockets are provided for each
channel. All are fully balanced, pin 2 hot, 3 cold, 1 screen.
Always replace the fuse with the correct type and rating as shown on the
rear panel legend.

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OPERATINGTHEDSO26
If you want to use the Proel EDGE and TFL presets you can skip this section and jump
directly to ‘Load a Xover’ page 26.
Preliminary Set-up
The procedure below should be followed when first installing a DSO26.
 Design your crossover! To do this, press MENU, and use the BACK or NEXT key to
select ‘X-over sub-menu’ and then press ENTER. Use the BACK or NEXT key to
select ‘Design a X-over’ and then press ENTER. Finally, use the BACK or NEXT
key to select the desired configuration and follow the set-up wizard to finalise your
design.
 Note that when in a menu, ENTER is always used to confirm selections. The
current selection is marked with an asterisk ‘*’.
 Use the GAIN keys on each output channel with the BACK and NEXT keys to select
the high pass filters, low pass filters, parametrics etc. Note that when designing a
new crossover, the high and low pass filters will be set to default values. See
appendix 2 for more information.
 Use the GAIN keys on each input channel with the BACK and NEXT keys to select
the gain and delay available on each input.
Note that if no action is taken in menu mode, the unit will return to normal ‘default’
mode after about twenty (20) seconds. Repeat the above directions to return to
menu mode.

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DSO26 CONFIGURATIONS
Introduction
To simplify the set-up of the DSO26, 5 crossover modes are selectable from the X-over
sub-menu. These all have parametric equalisers, high and low pass filters, gain controls,
delay and limiters. The following set of diagrams detail how each of the five modes is
internally configured. Note that the 2 x 3 way and 3 x 2 way modes also offer the option of
ganged parameter adjustment for stereo systems.
2 x 2 way with Mono Sum
This format feeds input A to outputs 1 and 2, designated low and high respectively. Input
B feeds outputs 3 and 4, low and high respectively. Outputs 5 and 6 are both fed from the
sum of inputs A and B. Output 6 is a full bandwidth output by default, with output 5 being
bandwidth limited as a sub output.
AES/EBU Digital input and output interfaces are available as an option (factory fitted only).
Input and output balancing transformers are also available as an option (factory fitted only).

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2 x 3 way
This format feeds input A to outputs 1, 2, and 3 designated low, mid, and high respectively.
Input B feeds outputs 4, 5, and 6, as low, mid, and high respectively.
Note that this configuration, as with the 2 x 2 way, can have the outputs ganged for stereo
operation. This gangs outputs 1 & 4, 2 & 5, and 3 & 6, so that they track identically. It can
be selected or modified by entering the ‘Design a Xover’ function again.
AES/EBU Digital input and output interfaces are available as an option (factory fitted only).
Input and output balancing transformers are also available as an option (factory fitted only).

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4 way + 2
This format feeds input A to outputs 1, 2, 3, and 4 designated low, lo-mid, hi-mid and high
respectively. Outputs 5 and 6 are configured as auxiliaries, with their source being either
input B, or the sum or inputs A and B.
AES/EBU Digital input and output interfaces are available as an option (factory fitted only).
Input and output balancing transformers are also available as an option (factory fitted only).
HPF LPF PEQ x 5 DELAY GAIN LIMIT MUTE
SELECT
ANALOGUE
DIGITAL
HPF LPF PEQ x 5 DELAY GAIN LIMIT MUTE
SELECT
ANALOGUE
DIGITAL
HPF LPF PEQ x 5 DELAY GAIN LIMIT MUTE
SELECT
ANALOGUE
DIGITAL
HPF LPF PEQ x 5 DELAY GAIN LIMIT MUTE
SELECT
ANALOGUE
DIGITAL
HPF LPF PEQ x 5 DELAY GAIN LIMIT MUTE
SELECT
ANALOGUE
DIGITAL
OUTPUT 1
LOW
OUTPUT 2
LO-MID
OUTPUT 3
HI-MID
OUTPUT 4
HIGH
OUTPUT 5
AUX 1
SELECT
ANALOGUE
DIGITAL
INPUT
A
GAIN MAIN DELAY
SUM
Σ
GAIN MAIN DELAY
SELECT
ANALOGUE
DIGITAL
INPUT
B
HPF LPF PEQ x 5 DELAY GAIN LIMIT MUTE
SELECT
ANALOGUE
DIGITAL
OUTPUT 6
AUX 2

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5 way + 1
This format feeds input A to outputs 1, 2, 3, 4, and 5 designated sub, low, lo-mid, hi-mid
and high respectively. Output 6 is configured as an auxiliary, with the source being either
input B, or the sum or inputs A and B.
AES/EBU Digital input and output interfaces are available as an option (factory fitted only).
Input and output balancing transformers are also available as an option (factory fitted only).

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6 way
This format feeds input A to all outputs designated lo-sub, through high, 1 to 6
respectively.
AES/EBU Digital input and output interfaces are available as an option (factory fitted only).
Input and output balancing transformers are also available as an option (factory fitted only).

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SCREEN LAYOUTS OVERVIEW
C
rossover Name
Default Screen
Interface Sub-Menu
AES/EBU Sub-Menu
System Sub-Menu
Security Sub-Menu
Input Section Screens Output Section Screens
PEQ’s 2 to 4

MENU-NEXTx2-ENTER

MENU-NEXTx3-
-ENTER

MENU-NEXTx4-
-ENTER

MENU-NEXTx5-
-ENTER

OUTPUT
GAIN

INPUT
GAIN
NEXT

NEXT

ENTER

MENU-NEXT-
-ENTER
Input Setup Sub-Menu

ENTER


ENTER

NEXT


MENU-ENTER

X
over Sub-Menu

NEXT

NEXT

ENTER


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AUDIO FUNCTION SCREENS
Gain Screen
To adjust the gain:
Use the ‘GAIN’ control.
Each input and output has an individual gain screen. The inputs have a range of +6dB to
–40dB, adjustable in 0.1dB steps and the outputs have a range of +15dB to –40dB, again
adjustable in 0.1dB steps.
For further details on this topic, see the section entitled
“Operating Level” on page 32.

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Polarity Screen
To adjust the polarity:
Use the ‘GAIN’ control to switch between + and -.
Each output has an independent polarity screen. This gives the flexibility to reverse (flip by
180°) the phase of individual outputs.
Note: When the outputs are ganged, the polarity screens remain individual.

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Delay Screen
To adjust delay settings:
Use the ‘DELAY’ control for coarse control. (1mS steps)
Use the ‘FINE DELAY’ control for fine control. (2.6µS steps)
Each input and output has an independent delay time control. Input delay (base delay) is
adjustable in 1mS steps. Output delay is adjustable in 2.6µS steps or in 1mS steps giving
complete control over driver time alignment.
The combination of input (base) delay and output delay can be a maximum of 650mS. So,
for example, setting a base delay of 500mS on input A will only leave 150mS for any
outputs that are sourced from input A. The exception to this rule is for any ‘aux’ outputs
(available in 4 and 5 way crossover modes). Choosing the source as a mono sum (Inputs
A + B) will allow 650mS of output delay, regardless of the input delay settings.
For further details on this topic, see the section entitled “Time Alignment” on
page 33.