Toa M-633D CE User manual

OPERATING INSTRUCTIONS
DIGITAL STEREO MIXER M-633D CE
M-633D CE-GB
M-633D CE-AU
Thank you for purchasing TOA’s Digital Stereo Mixer.
Please carefully follow the instructions in this manual to ensure long, trouble-free use of your equipment.

2
TABLE OF CONTENTS
1. IMPORTANT SAFETY INSTRUCTIONS ............................................. 3
2. SAFETY PRECAUTIONS ............................................................................. 4
3. GENERAL DESCRIPTION .......................................................................... 6
4. FEATURES ............................................................................................................ 6
5. HANDLING PRECAUTIONS ...................................................................... 6
6. NOMENCLATURE AND FUNCTIONS ................................................. 7
Front ............................................................................................................................. 7
Rear ............................................................................................................................. 8
7. ASSIGNMENT SETTINGS ........................................................................... 9
8. USING THE SUMMING OUTPUT KEYS .......................................... 10
9. SETTING THE ARC FUNCTION ........................................................... 11
9.1. What is the Automatic Resonance Control (ARC) Function? .............................. 11
9.2. Outline of the ARC Function Settings ................................................................. 11
9.3. Enabling the ARC Function ................................................................................. 13
9.4. Making Fine Acoustic Adjustment ....................................................................... 19
9.5. Disabling the ARC Function ................................................................................ 20
10. SETTING THE FBS FUNCTION .......................................................... 21
10.1. What is the Feedback Suppressor Function (FBS)? ......................................... 21
10.2. Setting the FBS Function .................................................................................. 21
11. SETTING THE AUTOMATIC MUTE FUNCTION ..................... 22
11.1. What is the Automatic Mute Function (AUTO MUTE)? ...................................... 22
11.2. Setting the Automatic Mute Function ................................................................ 22
12. AUTOMATIC CLIPGUARD (ACG) FUNCTION .......................... 23
13. RESETTING TO FACTORY DEFAULT SETTINGS ................. 24
14. MOUNTING IN A RACK ........................................................................... 25
15. CONNECTION ................................................................................................ 26
15.1. Connection Example ......................................................................................... 26
15.2. Phantom Power Supply ..................................................................................... 26
15.3. Removable Terminal Plug Connection .............................................................. 27
16. BLOCK DIAGRAM ....................................................................................... 28
17. DIMENSIONAL DIAGRAM ...................................................................... 30
18. SPECIFICATIONS ........................................................................................ 31
Accessories ............................................................................................................... 32

3
• Lire ces instructions.
• Conserver ces instructions pour référence
ultérieure.
• Respecter tous les avertissements.
• Suivre toutes les instructions.
• Ne pas utiliser cet appareil à proximité d'eau.
• Nettoyer uniquement à l'aide d'un chiffon sec.
• Ne pas obstruer les orices de ventilation. Installer
conformément aux instructions du fabricant.
• Ne pas installer à proximité de sources de chaleur
telles que des radiateurs, des registres thermiques,
des chaudières ou d'autres appareils (notamment
des amplicateurs) produisant de la chaleur.
• Ne pas contourner la fonction de sécurité de la che
polarisée ou de mise à la terre. Une che polarisée est
équipée de deux broches, dont l'une est plus large que
l'autre. Une che de mise à la terre est équipée de deux
broches et d'une troisième pour la mise à la terre. Cette
dernière, la plus large, est prévue à des ns de sécurité.
Si la che fournie ne peut être insérée dans la prise
électrique souhaitée, consulter un électricien pour faire
remplacer cette dernière.
• Protéger le cordon d'alimentation pour éviter qu'il
ne soit piétiné ou pincé, notamment au niveau des
ches, des prises de courant ou de son point de
sortie de l'appareil.
• Utiliser uniquement les accessoires spéciés par le
fabricant.
•
Utiliser uniquement avec le
chariot, support, trépied, la patte
de montage ou la table spéciés
par le fabricant ou vendus avec
l'appareil. En cas d'utilisation
d'un chariot, manipuler la
combinaison chariot/appareil
pour éviter les blessures dues à
un renversement.
• Débrancher cet appareil pendant les orages ainsi
que lorsqu'il reste inutilisé pendant une période
prolongée.
• La maintenance de l'appareil doit être conée à un
technicien après-vente qualié. Une maintenance
s'avère nécessaire si l'appareil est endommagé
(au niveau du cordon d'alimentation ou de la che),
a été mouillé par un liquide, un objet est tombé à
l'intérieur, s'il a été exposé à la pluie ou l'humidité,
s'il ne fonctionne pas normalement ou s'il est tombé.
• Read these instructions.
• Keep these instructions.
• Heed all warnings.
• Follow all instructions.
• Do not use this apparatus near water.
• Clean only with dry cloth.
• Do not block any ventilation openings. Install in
accordance with the manufacturer's instructions.
• Do not install near any heat sources such as
radiators, heat registers, stoves, or other apparatus
(including amplifiers) that produce heat.
• 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 fit into your outlet, consult an electrician for
replacement of the obsolete outlet.
• Protect the power cord from being walked on
or pinched particularly at plugs, convenience
receptacles, and the point where they exit from the
apparatus.
• Only use attachments/accessories specified by the
manufacturer.
• Use only with the cart, stand,
tripod, bracket, or table specified
by the manufacturer, or sold with
the apparatus. When a cart is
used, use caution when moving
the cart/apparatus combination
to avoid injury from tip-over.
• Unplug this apparatus during lightning storms or
when unused for long periods of time.
• Refer all servicing to qualified 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.
1. IMPORTANT SAFETY INSTRUCTIONS
INSTRUCTIONS ESSENTIELLES POUR LA SÉCURITÉ

4
2. SAFETY PRECAUTIONS
• Before installation or use, be sure to carefully read all the instructions in this section for correct and safe
operation.
• Be sure to follow all the precautionary instructions in this section, which contain important warnings and/or
cautions regarding safety.
• After reading, keep this manual handy for future reference.
Safety Symbol and Message Conventions
Safety symbols and messages described below are used in this manual to prevent bodily injury and property
damage which could result from mishandling. Before operating your product, read this manual rst and
understand the safety symbols and messages so you are thoroughly aware of the potential safety hazards.
Indicates a potentially hazardous situation which, if mishandled, could
result in death or serious personal injury.
Indicates a potentially hazardous situation which, if mishandled, could
result in moderate or minor personal injury, and/or property damage.
WARNING
CAUTION
AVERTISSEMENT
WARNING
When Installing the Unit
Lors de l’installation de l’appareil
• Do not expose the unit to rain or an environment
where it may be splashed by water or other liquids,
as doing so may result in re or electric shock.
• Ne pas exposer l’appareil à la pluie et le protéger de
tout contact avec de l’eau ou d’autres liquides an
d’éviter un incendie ou une électrocution.
• Use the unit only with the voltage specied on
the unit. Using a voltage higher than that which is
specied may result in re or electric shock.
• Do not cut, kink, otherwise damage nor modify
the power supply cord. In addition, avoid using the
power cord in close proximity to heaters, and never
place heavy objects -- including the unit itself -- on
the power cord, as doing so may result in re or
electric shock.
• Avoid installing or mounting the unit in unstable
locations, such as on a rickety table or a slanted
surface. Doing so may result in the unit falling
down and causing personal injury and/or property
damage.
• Since the unit is designed for in-door use, do not
install it outdoors. If installed outdoors, the aging of
parts causes the unit to fall off, resulting in personal
injury. Also, when it gets wet with rain, there is a
danger of electric shock.
When the Unit is in Use
• Should the following irregularity be found during
use, immediately switch off the power, disconnect
the power supply plug from the AC outlet and
contact your nearest TOA dealer. Make no further
attempt to operate the unit in this condition as this
may cause re or electric shock.
· If you detect smoke or a strange smell coming from
the unit.
· If water or any metallic object gets into the unit
· If the unit falls, or the unit case breaks
· If the power supply cord is damaged (exposure of
the core, disconnection, etc.)
· If it is malfunctioning (no tone sounds.)
• To prevent a re or electric shock, never open nor
remove the unit case as there are high voltage
components inside the unit. Refer all servicing to
qualied service personnel.
• Do not place cups, bowls, or other containers of
liquid or metallic objects on top of the unit. If they
accidentally spill into the unit, this may cause a re
or electric shock.
• Do not insert nor drop metallic objects or ammable
materials in the ventilation slots of the unit's cover
as this may result in re or electric shock.
• The socket-outlet shall be installed near the
equipment and the plug shall be easily accessible.
• The apparatus shall be connected to a main socket
outlet with a protective earthing connection.
In Finland:
“Laite on liitettävä suojamaadoituskoskettimilla
varustettuun pistorasiaan„
In Norway:
“Apparatet må tilkoples jordet stikkontakt„
In Sweden:
“Apparaten skall anslutas till jordat uttag„

5
CAUTION
When Installing the Unit
• Never plug in nor remove the power supply plug
with wet hands, as doing so may cause electric
shock.
• When unplugging the power supply cord, be sure to
grasp the power supply plug; never pull on the cord
itself. Operating the unit with a damaged power
supply cord may cause a re or electric shock.
• When moving the unit, be sure to remove its power
supply cord from the wall outlet. Moving the unit
with the power cord connected to the outlet may
cause damage to the power cord, resulting in re or
electric shock. When removing the power cord, be
sure to hold its plug to pull.
• Do not block the ventilation slots in the unit's cover.
Doing so may cause heat to build up inside the
unit and result in re. Also, periodically clean the
ventilation slots of dust.
• Avoid installing the unit in humid or dusty locations,
in locations exposed to the direct sunlight, near the
heaters, or in locations generating sooty smoke
or steam as doing otherwise may result in re or
electric shock.
• Be sure to follow the instructions below when rack-
mounting the unit. Failure to do so may cause a re
or personal injury.
· Install the equipment rack on a stable, hard oor.
Fix it with anchor bolts or take other arrangements
to prevent it from falling down.
· When connecting the unit's power cord to an AC
outlet, use the AC outlet with current capacity
allowable to the unit.
(Every version except the M-633D CU for US)
· The supplied rack-mounting screws can be used for
the TOA equipment rack only. Do not use them for
other racks.
(M-633D CU for US)
· Rack-mounting screws are not supplied with the
unit. Prepare them that are appropriate for the
equipment rack.
· Be sure to complete installation and cable
connections before connecting the unit’s power
plug to the power source. When uninstalling the
unit or disconnecting the unit’s cables, be sure to
disconnect the power plug from the power source
rst. Doing otherwise may result in electrical shock.
When the Unit is in Use
• If dust accumulates on the power supply plug or
in the wall AC outlet, a re may result. Clean it
periodically. In addition, insert the plug in the wall
outlet securely.
•
Switch off the power, and unplug the power supply plug
from the AC outlet for safety purposes when cleaning
or leaving the unit unused for 10 days or more. Doing
otherwise may cause a re or electric shock.
The lighting 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 sufcient magnitude to constitute a risk of electric shock to persons.
The exclamation point within an equilateral triangle is intended to alert the user to the presence
of important operation and maintenance (servicing) instruction in the literature accompanying the
appliance.
L’éclair accompagné d’un symbole représentant une pointe de èche à l’intérieur d’un triangle équilatéral
avertit l’utilisateur de la présence d’une “tension dangereuse” à l’intérieur de l’enceinte du téléviseur,
dont la magnitude peut être sufsante pour constituer un risque de choc électrique pour les personnes.
Le point d’exclamation à l’intérieur d’un triangle équilatéral avertit l’utilisateur de l’existence
d’instructions d’utilisation et d’entretien (réparation) dans la documentation fournie avec l’appareil.
Connect the mains cord to an easily accessible mains socket or power distributor with a switch or
breaker that is easily accessible. Reason: In case of a danger (smoke, fire), you can quickly disconnect
the device from a dangerous voltage (mains).

6
3. GENERAL DESCRIPTION
The M-633D is a stereo mixer with digital signal processing functions such as Automatic Resonance Control
function (ARC), Feedback Suppressor function (FBS), Automatic Clipguard function (ACG), and Automatic Mute
function (AUTO MUTE).
It can be mounted in an EIA component rack (1U size*).
* 1U size = 44.5 mm (standard size)
4. FEATURES
• A stereo mixer equipped with 12 input channels (6 monaural inputs and 3 stereo inputs), and 6 output channels
(2 monaural outputs, 1 stereo output, and 1 stereo recording output).
• Assignable each input signal to 3 output channels individually (MONO OUT 1, MONO OUT 2, and STEREO
OUT).
• Sound reproduction owing to automatic clarity control (ARC function).
• Automatic feedback suppressor (FBS function).
• Automatic input sensitivity control when an excessive input signal is applied to the monaural input (ACG
function).
• Stereo input muted automatically by detecting the monaural input signal (Automatic Mute function).
• Input sensitivity switchable to either –10 dB or –46 dB for the monaural inputs.
• The monaural inputs capable of supplying phantom power (+24 V, 10 mA).
• Assignment switch cover for protecting the assigned setting positions of each input usable as a signal name
writing plate.
• Easy function settings using the front and rear panel controls.
5. HANDLING PRECAUTIONS
• The supplied power supply cord is designed for exclusive use with this unit. Never use it with other equipment.
• The unit must be always installed inside a cabinet rack during use.
• Install the unit in locations where the temperature is between 0 and 40 °C (32 and 104 °F) and the moisture
is less than 90% (no dew condensation must be formed).
• The M-633D is a precision audio component. To prevent failure, avoid locations where the unit may be
exposed to strong shocks or vibrations.
• To clean, be sure to rst switch off the unit's power, then wipe with a dry cloth. When the unit gets very dirty,
use a cloth damped in a neutral cleanser. Never use benzene, thinner, alcohol, or chemically-treated cleaning
cloth because such volatile liquids could deform or discolor the unit.

7
345
98 10 1
2
11
16151412 1213
6
7
6. NOMENCLATURE AND FUNCTIONS
[Front]
1. Power switch
Press this switch to turn on the power. To turn off
the power, press this switch again.
2. Power indicator
Lights green when the power is switched on.
3. Assignment switch cover
A cover for protecting the setting positions of the
Assignment switches (16) and ARC switch (4). It
can be used as a writing plate.
4. ARC switch
Press this switch to enable the Automatic
Resonance Control function (ARC).
Hold down this switch for 3 seconds to start the
ARC measurement. Release the switch when the
ARC operation indicator (8) begins to ash. (See
p. 13.) Use a ne-tipped screwdriver to press in
the switch.
5. Output level indicators
Light green when the output sound level is
appropriate.
Light red when the output signal reaches 6 dB
below clipping level.
Light orange when the ARC switch is pressed if the
ARC lter has been previously set.
6. Summing output keys
Output the stereo input signals of each channel to
the stereo "L" and "R" outputs (17) in stereo mode
when not pressed and in monaural mode (summing
output) when pressed. (See p. 10.)
7. Stereo input level control knobs
Adjust the stereo input levels.
8. ARC operation indicator
Lights green when the ARC function is operating.
9. Monaural output level control knobs
Adjust the monaural output levels.
10. Stereo output level control knob
Adjusts the stereo output level.
11. Front-mounted stereo input jack
–10 dB*, 10 kΩ, unbalanced type.
Connect a stereo mini plug to this jack.
It is internally connected in parallel to the STEREO
IN 1 (24) on the rear panel. Adjust the input level
with the STEREO 1 input level control knob (7).
* 0 dB = 1 V
12. Input level indicators
Light green when the output sound level is
appropriate.
Light red when the internal signal reaches 6 dB
below clipping level.
13. FBS keys
Press this switch to enable the Feedback
Suppression function (FBS).
Holding down the key for 1 second switches
between on and off states of the FBS function.
14. FBS operation indicators
Light green when the FBS function is operating.
15. Monaural input level control knobs
Adjust the monaural input levels.
16. Assignment switches
Used to select the output destination to which the
post-fader input signals of each input channel are
routed. (See p. 9.)
Press in an individual switch to set the
corresponding output destination as follows. To
release, press it in again.
1: MONO 1 output, 2: MONO 2 output,
ST: STEREO output.
Use a ne-tipped screwdriver to press in the
switch.

8
This mark is a declaration that this product complies with
all applicable EU directive and regulations.
This symbol stands for a functional ground terminal. When a audio system produces hum noise,
then connecting the ground connections between several audio devices may reduce or eliminate it.
IMPORTANT NOTE: This is no protective ground!
Do not trash this device into normal waste.
Use the foreseen electric waste collection places.
18
17 19
20 21 22 23 24 25
[Rear]
17. Stereo output terminals
0 dB*, 1 kΩ, electronically balanced type.
Use the supplied removable terminal plug for
connection.
18. Auto mute switch
Used to turn on and off the Automatic Mute
function (AUTO MUTE).
19. Input sensitivity selector switches
Used to select the input sensitivity and phantom
power ON/OFF.
Note
Set to "PHANTOM" only when connecting a
microphone which requires phantom power (+24
V, 10 mA) to the corresponding input terminal.
Connecting an equipment other than this type of
microphone to the input terminal set to PHANTOM
may cause the unit to malfunction or may generate
hum noise.
20. AC inlet
Connect this inlet to the AC wall outlet using the
supplied power cord.
21. Functional ground terminal
Hum noise may be generated when external
equipment is connected to the unit. Connecting
this terminal to the functional ground terminal
of the external equipment may reduce the hum
noise.
Note: This ground is not for protective ground.
22. Monaural output terminals
0 dB*, 1 kΩ, electronically balanced type.
Use the supplied removable terminal plug for
connection.
23. Recording output terminal
–10 dB*, 1 kΩ, unbalanced type.
Use an RCA plug for connection.
24. Stereo input terminals
–10 dB*, 10 kΩ, unbalanced type.
Use an RCA plug for connection.
STEREO IN1 is internally connected in parallel to
the front-mounted stereo input jack (11).
25. Monaural input terminals
Input level can be selected by the input level
selector switch (19) position as follows.
LINE: –10 dB*/2.4 kΩ
MIC: –46 dB*/2.4 kΩ
PHANTOM: –46 dB*/2.4 kΩ
Removable terminal blocks and phone jacks
are provided. Both terminals are electronically
balanced type and internally connected in parallel.
* 0 dB = 1 V

9
7. ASSIGNMENT SETTINGS
It is possible to assign each input to 3 output channels individually (MONO 1, MONO 2, and STEREO).
MONO IN 1
Input
Output
Assignment switch
MONO IN 2
MONO IN 3
ST OUT L/R
1 2 ST
MONO OUT 2
MONO OUT 1
Pressing the Assignment switch "1" routes the input signal to the MONO OUT 1 output, switch "2" to the MONO
OUT 2 output, and switch "ST" to the STEREO OUT output.
Input signals assigned to the same output destination are mixed.
[Assignment setting example]
The gures below show an example of assignment settings of the inputs.
The gure below shows a signal ow.
MONO 1
Assignment switch
1, 2
MONO 2 2, ST
MONO 3 1
Input
MONO 2
MONO 1
MONO 3
: Pressed-in state (ON)
Mixed signals of the MONO IN 1 and MONO IN 3 are output from the MONO OUT 1, those of the MONO IN 1
and MONO IN 2 from the MONO OUT 2, and the MONO IN 2 signal from the ST OUT L/R.

10
8. USING THE SUMMING OUTPUT KEYS
It is possible to output the stereo input signals applied to the STEREO 1 – 3 to the stereo "L" and "R" outputs
either in stereo mode or monaural mode.
Summing output key
Input Output
L
R
L
R
Output
Input
L
R
L
R
[When the summing output key is not pressed in (ST position)]
The "L" channel’s input signal is output to the stereo "L" channel output, and the "R" channel’s input signal to
the stereo "R" channel output.
[When the summing output key is pressed in (MONO position)]
Signals applied to each of the input "L" and "R" channels are mixed and output to the stereo "L" and "R" outputs.

11
9. SETTING THE ARC FUNCTION
9.1. What is the Automatic Resonance Control (ARC) Function?
It is a function that automatically creates a sound eld compensation lter (ARC lter) to improve sound
clarity by measuring the inherent acoustic characteristics in architectural space.
9.2. Outline of the ARC Function Settings
The ARC function automatically creates an ARC lter, thereby reproducing highly clear output sound.
9.2.1. Enabling the ARC function (See p. 13 for details.)
Note
Before operating the ARC function, check that sound is actually output from the speakers after installation
and connection completion.
Select with the Assignment switches the output channel to which the ARC lter is to be set, hold down the
ARC switch for 3 seconds, then release it when the ARC operation indicator begins to ash.
The ARC measurement starts.
The ARC lter is set when the measurement has nished, enabling the ARC function. (The ARC operation
indicator lights.)
Note: To stop measurement partway, press the ARC switch again.
Flashing during
measurement
Measurement in progress
Measurement stops.
Press
ARC
ARC
ARC ARC
Lit
ARC
Unlit
Hold down for
3 seconds.
ARC
Release when the indicator
begins to flash.
9.2.2. Disabling the ARC function (See p. 20 for details.)
Holding down the ARC switch for 8 seconds or more with all the 3 assignment switches of the MONO 1 in
OFF mode (unpressed state) causes the ARC operation indicator to ash. Then it goes off, disabling the ARC
function.
Flashing
ARC
ARC ARC
Unlit
ARC
Lit
Hold down for
8 seconds or more.
ARC
Release when
the indicator goes off.
3 – 8 seconds
0 – 3 seconds After 8 seconds

12
Press briefly,
then release.
Light orange.
An example that the ARC filter is set to
the MONO OUT 1 and MONO OUT 2 channels.
ARC
Unlit
ARC measurement
in progress ARC filter ON ARC filter OFF
LitFlashing
ARC ARC ARC
Connect a measuring microphone*, then check if it works.
Make an initial setting of input and output levels.
Conduct ARC measurement.
ARC function is enabled.
Install the microphone.
Set the output channel and output level.
* The microphone for normal use can be used.
9.2.3. How to confirm the ARC enabled channel
The output level indicator of the ARC enabled (ARC lter preset) output channel lights orange when the ARC
switch is pressed.
9.2.5. ARC measurement procedure
9.2.4. ARC operation indicator status
(See Step 1 on p. 13.)
(See Step 2 and 3 on p. 14.)
(See Step 4 and 5 on p. 15.)
(See Step 6 on p. 16.)
(See Step 7 on p. 17.)

13
1-1
1-2
9.3. Enabling the ARC Function
Notes
• The ARC lter is created on the output channel selected with the Assignment switches at the ARC
measurement.
• The ARC lter previously set on the output channel will be updated by the newly created ARC lter after the
ARC measurement.
• To initialize the ARC lter, disable the ARC function. (See p. 20.)
The ARC lters for all the output channels are initialized. They cannot be initialized individually.
• Use a ne-tipped screwdriver to press in the Assignment and ARC switches.
Step 1. Make an initial setting of the input and output levels.
1-1. Turn all the output level control knobs to the "0" position.
1-2. Turn the MONO 1 input level control knob to the 12 o'clock position.
1-3. Fully turn down the output volume of the connected amplier.

14
2-1
2-2
Input level indicator (lit green)
When a dynamic
microphone is used
When a condenser
microphone is used
When the indicator does not light
Step 2. Connect a measuring microphone.
The microphone for normal use can be used.
2-1. Connect the microphone to the phone jack or removable
terminal block of MONO IN 1/ARC on the rear panel.
2-2. Set the input sensitivity selector switch to the appropriate
position depending on the microphone to be connected.
Dynamic microphone: MIC
Phantom powered condenser microphone: PHANTOM
Wireless tuner output (Line level): LINE
Step 3. Check to see if the microphone works correctly.
3-1. Speak into the microphone.
Conrm that the MONO 1’s input level indicator lights green.
Notes
• Hold the microphone about 7 cm (3") from the mouth. Speak at a normal voice level.
• Sound is not output from the speakers at this stage as the unit's output level control knobs are turned
fully counterclockwise.
3-2. Check to see the following settings if the input level indicator does not light green.
Input signal is too small.
• Check that the microphone switch is turned ON.
• Check that the rear-mounted input sensitivity selector switch is placed in the correct position for the
microphone.

15
Input signal is too big.
• Check the position of the input sensitivity selector switch on the unit's rear panel.
Try to set the switch to "LINE."
5-1
4
When the indicator lights red
Step 4. Select the output channel.
Press in the MONO 1’s assignment switch corresponding to the output channel to which the ARC lter
is set.
Step 5. Set the output volume level.
5-1. Turn the output level control knob corresponding to the assignment switch selected in Step 4 to the 12
o'clock position. (Setting example of MONO OUT 1)
5-2. Adjust the power amplier's volume level.
Speaking into the connected measuring microphone, adjust the volume to the level normally used with
the volume control knob of the amplier connected to the unit.

16
Step 6. Install the measuring microphone.
It is recommended to install the microphone as shown below as a guide.
45°
[Microphone setting example]
[Microphone setting example]
Location of the microphone: About the center of the room
Height of the microphone: At the listening position
Angle of the microphone: 45 º up
Location of the microphone: About the center of the room
(See the figure below.)
Direction of the microphone: Point to the speaker. (See the figure below.)
School room: Point to a platform.
Gymnasium and multipurpose auditorium: Point to the center of the stage.
Conference room: Point to the chairperson.

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Step 7. Conduct ARC measurement.
Notes
• To stop measurement partway, press the ARC switch.
• Never operate the switches and knobs of the unit and the external equipment during the ARC measurement.
[ARC measurement operation]
A 3-stage operation shown on the next page is performed during the ARC measurement.
Different tones sound in each operation stage.
The ARC operation indicator ashes slowly during normal measurement, but it begins to ash rapidly when a
failure occurs.
ARC Switch
ARC operation indicator
Flashes during
the measurement.
Measurement in progress
Measurement stops.
Press
ARC
ARC
ARC
ARC
Unlit
Hold down for
3 seconds.
ARC
Release when the indicator
begins to flash.
Measurement progresses normally
ARC operation indicator status
A failure occurs
Flashing slowly
ARC
Flashing rapidly
ARC
Hold down the ARC switch for 3 seconds.
The ARC operation indicator begins to ash and the measurement starts.

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Measurement starts.
Volume adjustment: Specific tone sounds twice.
Distance measurement: Specific tone sounds twice.
Measurement is complete.
Sound field measurement: Specific tone sounds 3 times.
The signals input to the MONO 2 – 6, and STEREO 1 – 3 are muted during
measurement. (Only MONO 1's signal is output.)
The FBS function and Automatic mute function are temporarily turned OFF.
MONO 1 is not assigned to any output.
Check the assignment setting.
When the ARC operation indicator flashes rapidly
soon after measurement starts.*
Input level is too small.
• Speak into the microphone, and check that voice is output from the
speaker.
• Increase the input level by turning the MONO 1's input level control
knob clockwise.
When the ARC operation indicator flashes rapidly*
Large noise is detected.
Adjust the microphone direction. Also, check the presence of large
ambient noise.
When the ARC operation indicator flashes rapidly*
* Perform the following reset operation if these errors occurred.
1. Stop the measurement by pressing the ARC switch.
The ARC indicator stops flashing, then goes off or lights steady.
2. Remedy the cause of the failure, then restart the ARC
measurement in Step 7.
Flashing
ARC operation indicator
Lit green
Output level indicator
Unlit *1Flashing orange
for 1 second. *2
*1The indicator may light green depending on the input level
of the microphone.
*2The output level indicator of the channel where the ARC
filter has already been set flashes orange even when this
channel was not assigned at the time of ARC measurement.
ARC ARC
Measurement is complete, and the ARC filter is set.
The output level indicator of the ARC enabled output channel ashes orange for 1 second.
In this case, the ARC operation indicator changes from ashing to steady on (green). The ARC lter data is
automatically saved, and remains effective even after power is cycled.
Note
After measurement completion, move the microphone to your desired location.
(See Step 4 on p. 15)

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9.4. Making Fine Acoustic Adjustment
When ner acoustic adjustment is required, different ARC lters can be set for individual output channels.
[Setting example in a gymnasium where the unit's output channels are assigned as follows]
Set different ARC lters to the MONO OUT 1 channel and STEREO OUT channel.
MONO OUT 1 channel
STEREO OUT channel
1-3
1-2
Press in (ON).
1-1. Turn the MONO 1's input level control knob to the 12 o'clock
position.
1-2. Press in only the MONO 1’s Assignment switch "1" to turn it
ON.
1: ON
2: OFF
ST: O FF
1-3. Turn the MONO 1's output level control knob to the 12
o'clock position.
1-4. Adjust the volume level of the output amplier connected to
the MONO OUT 1.
1-5. Conduct ARC measurement. (See Step 7 on p. 17.)
The ARC lter is assigned to the MONO OUT 1 channel.
Cable wiring example
• MONO OUT 1 channel: Ceiling speakers
• MONO OUT 2 channel: No connection
• STEREO OUT channel: Stereo speakers installed at
both sides of the stage
Step 1. Set the ARC lter only to the MONO OUT 1 channel (ceiling speakers).

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Step 2. Set ARC lter only to the STEREO OUT channel (Stereo speakers installed at both sides of the stage).
2-2
2-1
Press in (ON).
2
1
Flashing
ARC
ARC ARC
Unlit
ARC
Lit
Hold down for
8 seconds.
ARC
Release when
it goes off.
3 – 8 seconds
0 – 3 seconds After 8 seconds
2-1. Press in only the MONO 1’s assignment switch "ST" to turn it ON.
1: OFF
2: OFF
ST: O N
2-2. Turn the output level control knobs as follows.
MONO OUT 1: To the "0" position
STEREO OUT 2: To the 12 o'clock position.
2-3. Adjust the volume level of the output amplier connected to the
STEREO OUT.
2-4. Conduct ARC measurement. (See Step 7 on p. 17.)
The ARC filter is assigned to the STEREO OUT channel.
Different ARC lter settings are complete to each output of the MONO OUT 1 channel and STEREO OUT
channel.
The ARC lter data is automatically saved, and remains effective even after power is cycled.
9.5. Disabling the ARC Function
Step 1. Place the MONO 1’s all 3 assignment
switches in unpressed state.
Step 2. Hold down the ARC switch for 8
seconds.
The ARC operation indicator ashes
rapidly after 3 seconds.
Continue to hold it down for 5 seconds.
The ARC operation indicator goes off,
disabling the ARC function.