Audio Technica AT-DMM828 User manual

AT-DMM828
Digital Matrix Mixer
Installation and Operation

AT-DMM828
Digital Matrix Mixer
Installation and Operation
Warning:
To prevent fire or shock hazard, do not expose this apparatus to rain or
moisture.
Caution:
To avoid electric shock, do not open the cabinet.
Refer servicing to qualified personnel only.
To prevent fire, do not place any naked flame sources (such as lighted
candles) on this apparatus.
To prevent fire, do not cover the ventilation of this apparatus with
newspapers, table-clothes, curtains, etc.
Do not expose this apparatus to drips or splashes.
Do not place any objects filled with liquids, such as vases, on this apparatus.
Do not install this apparatus in a confined space such as a bookcase or
similar unit.
To install this apparatus only in the place where ventilation is good.
This apparatus should be located close enough to the AC outlet so that you
can easily grasp the power cord plug at any time.
In case of emergency, disconnect the power cord plug of this apparatus
quickly.
This apparatus with ClassⅠconstruction shall be connected to the AC outlet
with a protective grounding connection.
This apparatus is not disconnected from the mains as long as it is connected
to the AC outlet, even if the unit itself has been turned off.
Important Safety Instructions
1) Read these instructions.
2) Keep these instructions.
3) Heed all warnings.
4) Follow all instructions.
5) Do not use this apparatus near water.
6) Clean only with dry cloth.
7) Do not block any ventilation openings. Install in accordance with the
manufacturer’s instructions.
8) Do not install near any heat sources such as radiators, heat registers,
stoves, or other apparatus (including amplifiers) that produce heat.
9) Do not defeat the safety purpose of the polarized or grounding-type
plug.
A polarized plug has two blades with one wider than the other.
A grounding type plug has two blades and 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.
10) Protect the power cord from being walked on or pinched particularly at
plugs, convenience receptacles, and the point where they exit from the
apparatus.
11) Only use attachments/accessories specified by the manufacturer.
12) Use only with the cart, stand, tripod, bracket, or
table specified by the manufacturer, or sold with the
apparatus.
When a cart is used, use caution when moving the cart/
apparatus combination to avoid injury from tip-over.
13) Unplug this apparatus during lightning storms or when unused for long
periods of time.
14) Refer all servicing to qualified service personnel. Servicing is required
when the apparatus has been 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.
Caution for FCC
You are cautioned that any changes or modifications not expressly approved
in this manual could void your authority to operate this equipment.
Warning for FCC
This device complies with Part 15 of the FCC Rules. Operation is subject
to the following two conditions: (1)This device may not cause harmful
interference, and(2) this device must accept any interference received,
including interference that may cause undesired operation.
Note: This equipment has been tested and found to comply with the limits for
a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are
designed to provide reasonable protection against harmful interference in a
residential installation. This equipment generates, uses and can radiate radio
frequency energy and, if not installed and used in accordance with the
instructions, may cause harmful interference to radio communications.
However, there is no guarantee that interference will not occur in a particular
installation. If this equipment does cause harmful interference to radio or
television reception, which can be determined by turning the equipment off
and on, the user is encouraged to try to correct the interference by one or
more of the following measures:
- Reorient or relocate the receiving antenna.
- Increase the separation between the equipment and receiver.
- Connect the equipment into an outlet on a circuit different from that to
which the receiver is connected.
- Consult the dealer or an experienced radio/TV technician for help.
IC statement
CAN ICES-3 (B)/NMB-3(B)
About Power Cord
This model does not include AC power cord.
Therefore, you have to purchase it at your local store. You can confirm it at
“Power Cord List”.
Power Cord List
Power supply cord for 120 Vac power supply in U.S.A, Canada :
Approved by UL, CSA
Detachable, rated minimum 125 V, minimum 10 A, marked VW-1. Includes 3 x
18 AWG, Type SVT flexible cord. Minimum length 1.5 m.
One end terminates in a parallel blade, molded-on attachment plug rated 125
V, 10 A with a polarized NEMA 5-15P blade configuration.
Other end terminates in an appliance coupler.
2

3
Introduction
Please Note!
This manual assumes use of microphone-level inputs and line-level output
for most typical SmartMixer applications. However, all inputs may be
individually switched via the included AT-DMM828 Control Software to
achieve any combination of mic-level and line-level inputs.
Signal flow can be changed via the included AT-DMM828 Control Software.
Refer to Software Manual for more information.
About the AT-DMM828
AT-DMM828 is a microprocessor-controlled, programmable, automatic-
switching eight-channel matrix mixer. It can be used with low-impedance
either dynamic or condenser microphones (including wireless microphone
systems), as well as line-level sources.
AT-DMM828 is designed to improve audio quality in broadcast, sound-
reinforcement and recording applications. One way it achieves this is
by keeping the number of open microphones to minimum, thus reducing
background noise, feedback and other distractions, while providing instant,
completely transparent switching between channels.
Each of the eight balanced inputs provides switchable 48Volt phantom
power; attenuation is also selectable on each input to allow use with line-
level signals. The mixer's outputs are balanced and non-inverting. All audio
connections terminate in block screw connectors.
Up to 16 units of AT-DMM828 (a total of 128 channels inputs) can be daisy-
chained via CAT6 cable, which carries control bus, audio, and configuration
data between mixers.
Multiple mixers linked in this way will operate as if they are a single mixer.
Therefore, microphones activated on any mixer will cause the appropriate
switching functions to occur. The link connectors are not compatible with
LAN.
Each AT-DMM828 includes two separate external control system interfaces:
Individual channel contact closures (via DB25 connector) and PC control (via
RS232 connector or USB). The RS232 connector can also be used to connect
an external control system (e.g. Crestron®or AMX®) using “open disclosure
communication protocol” to control the mixer.
AT-DMM828 Features
• Eight balanced inputs allow to be used with either mic-level or line-level
signal.
Each input provides:
° 48V phantom power (individually selectable)
° Individual gain and sound volume controls
° Gate attenuation adjustable (0 dB to full mute in steps of 1 dB)
° Gate hold time adjustable (0.1 sec to 6.0 sec in steps of 0.1 sec)
° Mic on threshold level adjustable (Auto/Manual)
• DSP algorithm
° Signal level meter (Peak/RMS)
° Signal generator (Sine wave/Pink noise/White noise) *input
channel only
° Parametric EQ (3 band/4 band)
° Filter (Low pass/High pass/Low shelving/High shelving/Notch/All
pass)
° Limiter
° Delay *output channel only
° 8×8 full matrix-mixing (can be extended to 128×8 matrix-mixing)
• Selectable NOMA (Number of Open Microphones Attenuated)
° Automatic gain adjustment as each microphone is activated
• Selectable manual mode overrides automatic functions
• Linking capability for up to 16 units (up to 128 inputs)
• Selectable external connector’s pin assignment
° Gate status output (using for the Camera moving)
° Gate On/Off (using for input gate control by tactile switch)
°
Mute On/Off /Toggle (using for channel level control by tactile switch)
° Volume Up/Down (using for channel level control by tactile switch)
° VCA function (using for channel level control by external
potentiometer)
• Compatible with Crestron®or AMX®systems
• All settings can be adjusted or modified through AT-DMM828 Control
Software
• Mounts in a single U 19” rack space (EIA Standard)

4
Figure 1
Figure 2
AT-DMM828 Front Panel
AT-DMM828 Rear Panel
Figure 1 – AT-DMM828 Front Panel Layout
1. USB connector
To connect PC using its own software to configure internal settings
2. Link status indicator
LED lights green when linked normally and red when the error occurred
Figure 2 – AT-DMM828 Rear Panel Layout
6. AC Inlet
100-240V AC, 50/60Hz, 25W
7. External Control Connector (25-pin D-Sub Female)
Provides external connection points to control AT-DMM828 using
contact closures
8. Serial Data Connector (9-pin D-Sub Female))
RS232 data port allows PC to connect or as an interface port for Central
Control System like Crestron®, AMX®or other brands’ control systems
using open communication protocols to configure internal mixer settings
3. Power “ON” indicator
4. Power Switch
5. Fan will automatically turn on when internal temperature exceeds 60°C
(140°F).
9. Link In/Link Out connector (RJ-45)
Provides cascade connections of multiple mixers when more than eight
microphones are used
Use CAT6 cable. Maximum length is 0.5m.
NOTE: Use high quality CAT6 cable when linking mixers. Signal
degradation will occur with low quality cable or connections resulting in
communication errors between mixers.
10. Output Connectors (3-pin block screw connector)
Pin-1: Hot; Pin-2: Cold; Pin-3: Ground
Provides balanced mixing output
11. Input Connectors (3-pin block screw connector)
Pin-1: Hot; Pin-2: Cold; Pin-3: Ground
Provides balanced input
LINK I /O
AC IN
WARNING: THIS APPARATUS MUST BE EARTHED.
PC CONTROLEXTERNAL CONTROL
OUTPUT
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5
Installation and Setup
Computer requirements
Installing the software
Connecting the AT-DMM828 to the computer
Out of the box, the AT-DMM828 comes configured for most common applications.
Here are some basic setup tips to help quickly setup and running.
To run the software, the following minimum computer hardware and software configuration are required.
Note: It must have administrator rights for the computer to install the software.
1. Close all running applications
2. Insert the AT-DMM828 Software CR ROM into the computer’s CD ROM drive
Use “Browse” to locate the setup file on the CD ROM
3. When “Setup” is executed, the Setup welcome dialog box appears
4. Click OK to begin setup Wizard
Connect a standard 9-pin RS232 type data cable (or USB cable) between the computer and the RS232 port on the back panel (the USB port on the front panel) of
the AT-DMM828. If multiple AT-DMM828s are linked together, connect the data cable to the master unit in the linked chain.
Set the master unit to the bottom and connect to upper slave units.
Note: This software will not run on LINUX®or Mac OS based system.
Note: This software requires Microsoft. NET Framework 4 Client Profile. If the computer does not have. NET Framework 4 Client Profile installed, the installation
process will ask to install it during setup. After installation process finishes, it will ask to restart the computer.
Hardware:
Pentium processor running at 1.6 GHz or better
4 GB hard disk space recommended for application
1 GB RAM
9-pin RS232 Serial Data Port (Com Port) or USB interface
CD ROM Drive
Computer display capable of supporting at least 1024×768 pixel resolution
Operating System / Software:
Microsoft®Windows®XP SP3 and up including the following versions:
Windows Vista 32 bit version
Windows Vista 64 bit version
Windows 7 32 bit version
Windows 7 64 bit version
Windows 8 32 bit version
Windows 8 64 bit version
Installing the software
LINK I/ O
AC IN
WARNING: THIS APPARATUS MUST BE EARTHED.
PC CONTROLEXTERNAL CONTROL
OUTPUT
8765432
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INPUT
LINK I/ O
AC IN
WARNING: THIS APPARATUS MUST BE EARTHED.
PC CONTROLEXTERNAL CONTROL
OUTPUT
8765432
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INPUT
LINK I/ O
AC IN
WARNING: THIS APPARATUS MUST BE EARTHED.
PC CONTROLEXTERNAL CONTROL
OUTPUT
8765432
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INPUT
Slave#2
Slave#1
Master

Control Software Functions Explanation
Main Window
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1. Menu Bar
File: To save and to open files and it can also print the window
Edit: To copy and to paste operation blocks and it can also insert images
and texts
Setup: To set window parameters settings window, the software settings
window and communication settings window and it can restore mixer to
factory default settings
Window: To select the open windows
Image/Text: To select inserted images and texts
About: To check software version and firmware version
2. Online/Offline Indicator: Indicator will change to orange color when PC
and AT-DMM828 are connected, and Communications Settings window
can be displayed by double-click this indicator
3. Operations Block: To adjust the internal block of the mixer by dragging
and dropping these blocks (Refer to “Customizing the DSP block” &
Operations Blocks’ Descriptions)
4. Preset: maximum of 10 presets’ data can be saved in PC.
Yellow icon indicates it has already got preset data
Right-click either yellow or gray icon to save current setting
Left-click the yellow icon to load the preset data
5. Scale: Can adjust the scale of the main block by sliding the button
6. Unit: To select the unit to display its DSP usage
7. DSP Resource Monitor: To display each unit DSP processing usage
1. Orange color: Input block processing usage
2. Light Blue color: Output block processing usage
8. External Settings: Double-click this icon to display External Control
Terminal Settings window
9. Input Channel Settings: Double-click this icon to display Input channel
settings window
10. Matrix Mixer Settings: Double-click this icon to display Matrix mixer
settings window
11. Output Channel Settings: Double-click this icon to display Output
channel settings window
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Parameter Settings
7
1. Link Unit: Select the number of the system unit; change the number and
click the “Set” button
2. NOMA: Set number of Open Microphones Attenuated (NOMA) On/Off
3. Last Mic: Select the Last Mic On/Off.
- In any of the modes of operation, the last microphone “ON” will
remain “ON” when talking ceases, to provide continuous room
ambience
4. OpenCh: Set the maximum number of channel openings from 1 to 16;
select “Disable”, the number of channel openings is not restricted
5. Chairman: When the channel set as the chairperson becomes open,
other channels are closed compulsorily
- The number means that Master’s channel 1 is “1” and channel
2 is “2”. Slave#1’s channel 1 is “9” and channel 2 is “10”….
Slave#15’s channel 8 is “128”
6. Priority mode: This mixer has two priority modes
The maximum gate open number limits the number of open channels
over the system
- Mode 1: The channel to which the priority was set also receives
restriction of the number of the maximum channels
- Mode 2: The channel to which the priority was set does not
receive restriction of the number of the maximum channels
7. HoldTime: Select the gate hold time 0.1 to 6.0 sec (0.1 sec stepping)
8. Baudrate: It is a baud rate of a mixer, and it can change the baud rate in
the online mode. A preset value is reflected after a mixer reboots; 38400,
57600, & 115200 bps
9. Threshold K: Auto threshold sensitivity. A higher value will make it more
difficult to trigger the gate open. Range is 1.00 to 3.00 (0.01 stepping)
10. Threshold Max: The maximum dB that will trigger a gate to open.
Reducing the possibility of transient sounds false triggering the gate.
Range is -80 to 0dB (0.1 stepping)
11. Threshold Min: The minimum dB that will trigger a gate to open.
Reducing the possibility of gates closing and interrupting active
dialogue. Range is -80 to 0dB (0.1 stepping)
12. Correlation Coefficient: This value adjust the calculations used to
determine if multiple channels are receiving the same source. A higher
value will make it more likely for multiple microphones to pass the same
source.
This value is factory set and in most cases should remain at the default
level of 0.50. Range is 0.01 to 1.00 (0.01 stepping)
Suggestions for using multiple microphones: Proper adjustment of the
Threshold K for background noise and other non-intended audio will
ensure best operation of the auto-mixer.
Adjusting Threshold K: This level should be set to the ambient noise of the
room (Computer fans, video projector fans, HVAC, etc.) so as not to
trigger the gain reduction.
With two people speaking into two microphones adjust the Threshold
K until the gain reduction activates and stays on during short pauses
in speech. This value should be increased in high ambient noise
applications.
Adjusting Threshold Maximum: This controls false triggers of the automatic
gate regardless of the microphone channel gain setting. Setting this
level too low can cause transient sounds such as coughs or table
pounds to trigger a gate.
Adjusting Threshold Minimum: will help control false triggers of the
automatic gate regardless of the microphone channel gain setting.
Setting this level too high can cause the gate to cut off words.
NOMA or Number of Open Microphones Attenuator utilizes audio thresholds
to manage a shared total gain. As more microphone channels are opened,
the gain of each channel is attenuated to achieve the same total output level
regardless of the amount of microphone gates open.
There are the limits of this automix method. When using more than 10
channels the NOMA setting may not be achievable in "Auto-Mode”.
Directions for using a manual mode and optimizing each channel individually
can be found on (P.19).
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Communications Settings
RS232 Control Port
8
1. Serial Communication Speed: Adjustable range is 38400 to 115200 bps
*It is necessary to make it the same value as the baud rate of parameter
setup
2. Port: The port where the mixer connect/disconnect to the PC
A rear panel RS232 port (9-Pin) is provided to allow for the connection of a computer running the AT-DMM828 Control Software application or external control
system (Crestron®or AMX®) is using open disclosure communications protocol.
3. Serial Connect button: The mixer is connected or disconnected to the
PC via serial port
4. USB Connect button: Select connect or disconnect to the PC using USB
interface
5. Progressive Bar: The progress of connection will be displayed
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Software Settings
1. Language: Select the language that will display
a. Language available: English, German, Spanish, French, Italian,
Japanese, Korean, Dutch, Portuguese, Russian, Traditional Chinese,
Simplify Chinese
2. Software rendering: Number of Open Microphones Attenuated (NOMA)
is set
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Customize the DSP block
Adjust the internal block of this mixer in offline mode
A block which you want to add is chosen from an operation block
area and it dragging and dropping on the line of a channel.
The number of the blocks which can be arranged to each channel has restriction.
The delay block can arrange only to output side.
9
It can drop, if a line changes to pink.

Double-click “Equalizer” block, 3 Band EQ will display the following window
Operations Blocks’ Descriptions
●3 Band Equalizer Settings
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1. Unit name and Channel No: The unit name and channel number to
which this block is set will be displayed
2. Band: Click and select the band to adjust;
• 3 band EQ has Band 1 (100 Hz), Band 2 (500 Hz) and Band 3 (2500
Hz)
3. Equalizer type: Click and select the equalizer type;
• Low Shelving
• High Shelving
• Notch
• Bell (default)
4. Frequency: To select the center frequency (Hz) for the current band;
range is from 20 Hz to 20 kHz (1 Hz stepping)
5. Gain: To adjust the amount of boost or cut applied at the center
frequency for the current band from 9 to -27 dB (0.1 dB stepping);
default at 0 dB
6. Quality: Q or Quality factor, selects the ratio of the center frequency
divided by the bandwidth. Q reflects an inverse relationship to the
bandwidth, and adjust from 0.01 to 50.00 (0.01 stepping); default at 0.50
7. Bypass: When selected, it will bypass this filter
8. Quality dot: Q factor dot
9. Frequency square: These settings may be adjusted by dragging the
band controls shown inside the graph
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Double-click “Equalizer” block, 4 Band EQ will display the following window
●4 Band Equalizer Settings
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1. Unit name and Channel No: The unit name and channel number to
which this block is set will be displayed
2. Band: Click and select the band to adjust;
• 4 Band EQ has Band 1 (80 Hz), Band 2 (315 Hz), Band 3 (1250 Hz)
and Band 4 (5000 Hz)
3. Equalizer type: Click and select the equalizer type;
• Low Shelving
• High Shelving
• Notch
• Bell (default)
4. Frequency: To select the center frequency (Hz) for the current band;
range is from 20 Hz to 20 kHz (1 Hz stepping)
5. Gain: To adjust the amount of boost or cut applied at the center
frequency for the current band from 9 to -27 dB (0.1 dB stepping);
default at 0 dB
6. Quality: Q or Quality factor, selects the ratio of the center frequency
divided by the bandwidth. Q reflects an inverse relationship to the
bandwidth, and adjust from 0.01 to 50.00 (0.01 stepping); default at 0.50
7. Bypass: When selected, it will bypass this filter
8. Quality dot: Q factor dot
9. Frequency square: These settings may be adjusted by dragging the
band controls shown inside the graph
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Double-click “All Pass Filter” block, the following window will be displayed
Double-click “Notch Filter” block, the following window will be displayed
●All Pass Filter Setting
●Notch Filter Setting
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1. Unit name and Channel No: The unit name and channel number to
which this block is set will be displayed
2. Filter Type: Click to change to other filter type
3. Frequency: Adjust the center frequency from 20 Hz to 20 kHz (1 Hz
stepping)
1. Unit name and Channel No: The unit name and channel number to
which this block is set will be displayed
2. Filter Type: Click to change to other filter type
3. Frequency: Adjust the center frequency from 20 Hz to 20 kHz (1 Hz
stepping)
4. Gain: Fixed at 0 dB (non-adjustable)
5. Quality/Bandwidth: Adjust the quality of the filter; Q from 0.20 to 4
(0.01 stepping), default at 0.5; bandwidth (oct) from 4.74 to 0.36 (0.01
stepping), default at 2.55
6. Bypass: When selected, it will bypass this filter
4. Gain: Fixed at 0 dB (non-adjustable)
5. Quality: Adjust the quality of the filter; Q from 0.01 to 50.00 (0.01
stepping); default at 0.50
6. Bypass: When selected, it will bypass this filter
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Double-click “Low Pass Filter” block, the following window will be displayed
Double-click “High Pass Filter” block, the following window will be displayed
●Low Pass Filter Setting, -12 dB/oct
●High Pass Filter Setting, -12 dB/oct
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1. Unit name and Channel No: The unit name and channel number to
which this block is set will be displayed
2. Filter Type: Click to change to other filter type
3. Frequency: Adjust the cut-off frequency from 20 Hz to 20 kHz (1 Hz
stepping)
1. Unit name and Channel No: The unit name and channel number to
which this block is set will be displayed
2. Filter Type: Click to change to other filter type
3. Frequency: Adjust the cut-off frequency from 20 Hz to 20 kHz (1 Hz
stepping)
4. Gain: Fixed at -3 dB (non-adjustable)
5. Quality: Fixed at 0.71 (non-adjustable)
6. Bypass: When selected, it will bypass this filter
4. Gain: Fixed at -3 dB (non-adjustable)
5. Quality: Fixed at 0.71 (non-adjustable)
6. Bypass: When selected, it will bypass this filter
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Double-click “Low Pass Filter” block, the following window will be displayed
Double-click “High Pass Filter” block, the following window will be displayed
●Low Pass Filter Setting, -6 dB/oct
●High Pass Filter Setting, -6 dB/oct
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1. Unit name and Channel No: The unit name and channel number to
which this block is set will be displayed
2. Filter Type: Click to change to other filter type
3. Frequency: Adjust the cut-off frequency from 20 Hz to 20 kHz (1 Hz
stepping)
1. Unit name and Channel No: The unit name and channel number to
which this block is set will be displayed
2. Filter Type: Click to change to other filter type
3. Frequency: Adjust the cut-off frequency from 20 Hz to 20 kHz (1 Hz
stepping)
4. Gain: Fixed at -3 dB (non-adjustable)
5. Quality: Fixed at 0.71 (non-adjustable)
6. Bypass: When selected, it will bypass this filter
4. Gain: Fixed at -3 dB (non-adjustable)
5. Quality: Fixed at 0.71 (non-adjustable)
6. Bypass: When selected, it will bypass this filter
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Double-click “Low Shelving Filter” block, the following window will be displayed
Double-click “High Shelving Filter” block, the following window will be displayed
●Low Shelving Filter Setting
●High Shelving Filter Setting
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1. Unit name and Channel No: The unit name and channel number to
which this block is set will be displayed
2. Filter Type: Click to change to other filter type
3. Frequency: Adjust the cut-off frequency from 20 Hz to 20 kHz (1 Hz
stepping)
1. Unit name and Channel No: The unit name and channel number to
which this block is set will be displayed
2. Filter Type: Click to change to other filter type
3. Frequency: Adjust the center frequency from 20 Hz to 20 kHz (1 Hz
stepping)
4. Gain: Adjust the amount of cut or boost applied by the filter; gain at 9
dB to -27 dB (0.1 dB stepping)
5. Quality: Adjust the quality of the band; Q from 0.01 to 1.00 (0.01
stepping)
6. Bypass: When selected, it will bypass this filter
4. Gain: Adjust the amount of cut or boost applied by the filter; gain at 9
dB to -27 dB (0.1 dB stepping); default at -3.0 dB
5. Quality: Adjust the quality of the filter, Q from 0.01 to 50.00 (0.01
stepping); default at 0.71
6. Bypass: When selected, it will bypass this filter
①
①
②
②
③
③
④
④
⑤
⑤
⑥
⑥

Double-click “Limiter” block, the following window will be displayed
Double-click “Delay” block, the following window will be displayed
●Limiter Setting
●Delay Setting
16
1. Attack time: Determines how quickly the limiter reacts to input level
changes
- Adjustable range is 0 to 2000 ms (1 ms stepping)
2. Release time: Determines how quickly gain reduction is released,
once input signal falls below threshold.
- Adjustable range is 0 to 2000 ms (1 ms stepping)
1. Delay Time: Determines the amount of delay
- Adjustable range is 0 to 300ms (1 ms stepping)
2. Bypass button: Disables the delay without changing settings
3. Ratio: Determines the intensity of gain reduction
- Adjustable range is 1:1 to 20:1 (0.1 stepping)
4. Threshold: Determines what input level will trigger gain reduction
- Adjustable range is -80 to 0 dB (0.1 dB stepping)
5. Bypass button: Disables the limiter without changing settings
①
①
②
②
③
④
⑤

Orange color Input usage; Light Blue color Output usage
Unit 0, Master Unit, Selection and its DSP Resource Usage Display
Unit 1, Slave Unit 1, Selection and its DSP Resource Usage Display
Unit and DSP Resource Monitor
17

Double-click or “SlaveX” icon to load and display the External Control Terminal Settings window
External Settings
18
It must be in Offline mode to
perform settings
1. Enable/disable external
control
2. Drop-down menu
Mute – ON / OFF / Toggle
Volume - + 3.0 to -3.0
(1 dB stepping)
Gate – ON / OFF
VCA
Output
The following table show what functions is available for each pin assignment:
To increase the integration flexibility of the AT-DMM828 with external control and indicator devices, a rear panel connector (25-pin) is provide.
To activate mute-on/mute-off, volume-up/volume-down and gate-on/gate-off, install a closure between the appropriate pin and +3.3V
Reference on the External Control connector (24pin) on back of unit.
NOTE:
Audio-Technica legacy mixer provides the external control function which uses a "Low Active" (Ground Reference). AT-DMM828's external
control function uses a "High Active" (+3.3V Reference).
If you need to use a Low Active switch function, you need to add the following circuit.
Low Active interface circuit:
External Control Connector (25-Pin D-Sub)
①
②
Mute
PIN 1
X
Volume X
Gate X
VCA
Output X
2
X
X
X
X
3
X
X
X
X
4
X
X
X
X
5
X
X
X
X
6
X
X
X
X
7
X
X
X
X
8
X
X
X
X
9
X
X
X
10
X
X
X
11
X
X
X
12
X
X
X
13
X
X
X
14
X
X
X
15
X
X
X
16
X
X
X
X
17
X
X
X
X
18
X
X
X
X
19
X
X
X
X
20
X
X
X
X
21
X
X
X
X
22
X
X
X
X
23
X
X
X
X
1
Channel status output or Gate on/off or Mute on/off/toggle or Volume up/down
3
Channel status output or Gate on/off or Mute on/off/toggle or Volume up/down
5
Channel status output or Gate on/off or Mute on/off/toggle or Volume up/down
7
Channel status output or Gate on/off or Mute on/off/toggle or Volume up/down
9
Gate on/off or Mute on/off/toggle or Volume up/down
Gate on/off or Mute on/off/toggle or Volume up/down
Gate on/off or Mute on/off/toggle or Volume up/down
Gate on/off or Mute on/off/toggle or Volume up/down
VCA control or Gate on/off or Mute on/off/toggle or Volume up/down
VCA control or Gate on/off or Mute on/off/toggle or Volume up/down
VCA control or Gate on/off or Mute on/off/toggle or Volume up/down
VCA control or Gate on/off or Mute on/off/toggle or Volume up/down
GND
Pin#
Selectable Function
2
Channel status output or Gate on/off or Mute on/off/toggle or Volume up/down
4
Channel status output or Gate on/off or Mute on/off/toggle or Volume up/down
6
Channel status output or Gate on/off or Mute on/off/toggle or Volume up/down
8
Channel status output or Gate on/off or Mute on/off/toggle or Volume up/down
Gate on/off or Mute on/off/toggle or Volume up/down
Gate on/off or Mute on/off/toggle or Volume up/down
Gate on/off or Mute on/off/toggle or Volume up/down
VCA control or Gate on/off or Mute on/off/toggle or Volume up/down
VCA control or Gate on/off or Mute on/off/toggle or Volume up/down
VCA control or Gate on/off or Mute on/off/toggle or Volume up/down
VCA control or Gate on/off or Mute on/off/toggle or Volume up/down
+3.3V（for VCA control）
11
13
15
17
19
21
23
25
10
12
14
16
18
20
22
24
Pin#
Selectable Function
D-sub 24pin (+3.3V)
To AT-DMM828 D-sub25
Low active swich 10k
10k
1k
47k
D-sub 1- 23pin
for switch function
*Not use VCA
D-sub 25pin (GND)

Input Channel Settings
19
1. Gate control mode: To select Auto or Manual mode
2. Correlation: To select Valid or Invalid
Correlation of an input signal is judged and gate control of a contiguity
channel is performed
A judgment is performed in each unit
3. Input level meter response: To select RMS or PEAK metering
4. Channel name: To edit, double click the name and edit
5. Gain: Adjustable range is 26 to 51 dB (32 steps logarithmic scale)
6. Volume: Adjustable range is -80 to 0 dB (0.1 dB stepping)
7. Mute button: To mute each input channel
8. Input Attenuator and Phantom Power: Select either MIC or LINE. LINE is
already attenuated 30 dB
Select the phantom power (+48V) ON/OFF
9. Input source: To select input source Audio input or White noise /Pink
noise /Tone (for channel calibration)
10. Gate status: The gate status of the channel is indicated
11. Force-On/OFF button: To force the gate open or closed via software.
12. Gate priority: Set priority to each channel
13. Auto Target: To select ON or OFF mode, the channel which is set “Auto
Target” – “ON” mode: it becomes the calculation target for the gate
threshold in Auto mode
14. Gate Threshold: Adjustable range is -80 to 0 dB in Manual mode (0.1 dB
stepping)
15. Gate Attenuation: Set attenuation level for Mic-Off; adjustable range is
-80 to 0 dB (0.1 dB stepping)
④
① ② ③
⑤
⑥
⑦⑧
⑫
⑨
⑩
⑪
⑬
⑭
⑮
Double-click “Inputs” block, the following window will be displayed

Matrix Settings
20
1. Matrix Figure: Right-click on the point, to select the matrix connect or
disconnect
Green color represents connection; pink color represents no connection
Left-click on one of the squares, to adjust the sending level on the matrix
Sending level range is -80 to 0 dB (0.1 dB stepping)
When lower the sending level, the color of the squares will lighten
gradually to white color at 0 dB
2. There are 4 select buttons next to the Master Matrix block
a. Connect all: when click on this button, all input channels are
connected to all output channels
b. Disconnect all: when click on this button, all input channels are
disconnected to all output channels; there is no output
c. Diagonal: when click on this button, each input channel is only
connect to one respective output channel
d. Copy: this button is for 2 or more units linking together
• when 2 or more units,
the Matrix Mixer
Settings window will
have additional matrix
block that mark as
Slave input block linking
to Master outputs, as
show below
• Click the Copy button, the
following window will display
to allow selection any of the
connecting unit copy to other
connecting unit within the
linking system
• Click the Slave Output
bar will display the
output connection
within its own slave
unit and from the slave
unit or units connecting
below
①
Double-click “Mixer” block, the following window will be displayed