Lectrosonics DBu Quick Start Guide

Quick
Start
Guide

Digital Belt Pack Transmitter

Fill in for your records:

Serial Number:

Purchase Date:

Digital Hybrid Wireless® US Patent 7,225,135

This guide is intended to assist with
initial setup and operation of your
Lectrosonics product.

For a detailed user manual, down­load the most current
version at:

www.lectrosonics.com

31 May 2019

DBu Features and Functions

Modulation

Indicators*

IR Port

Function Switch

Programmable

Antenna

Port

Battery

status LED

Return to

previous screen

-20

AUDIO

IR PORT

DBu

470.100

-40

u

-10

-20

PWR/FUNC

+0

Audio

Input

Jack

Key verification

LED

Menu navigation

buttons

Power button

Belt clip

mounting hole

Battery

compartment

door

LECTROSONICS, INC.2

Belt clip

mounting hole

USB Port

Programmable Switch

The transmitter can also be configured as a “one button” device by locking the
ability to make changes with the keypad, and configuring the top panel switch
as either power on/off or a mute function.

Modulation Indicator LEDs

When the transmitter is set to MUTE, the -10 Modulation Indicators LED will
glow solid red. Otherwise, the -10 Modulation Indicators LED will glow solid
green when transmitter is on.

Belt Clips

The wire belt clip may be removed by pulling the ends out of the holes in the
sides of the case. Be sure to have a firm grip to avoid scratching the surface
of the housing.

An optional spring-loaded, hinged belt clip (model number BCSLEBN) is also
available. This clip is attached by removing the plastic hole cap on the back of
the housing and mounting the clip with the supplied screw.

IR (infrared) Port

The IR port is available on the top of the transmitter for quick setup using a
receiver with this function available. IR Sync will transfer the settings for fre­quency from the receiver to the transmitter.

Remove hole cap to

attach spring loaded

belt clip

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Battery Installation

The transmitter is powered by two AA batteries. We recommend using alka­line, lithium, or rechargeable batteries for longest life.

The battery status circuitry compensates for the difference in voltage drop
between alkaline and lithium batteries across their usable life, so it’s important
to select the correct battery type in the menu.

Because rechargeable batteries run down quite abruptly, using the Power
LED to verify battery status will not be reliable. However, it is possible to track
battery status using the battery timer function available in the receiver.

Push outward on the battery compartment door and lift it to open.

Slide door out to release catch

Lift door to open

Insert the batteries according to the markings on the back of the housing.

If the batteries are inserted incorrectly, the door will close but the unit will not
operate.

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The battery contacts can be cleaned with alcohol and a cotton swab, or a
clean pencil eraser. Be sure not to leave any remnants of the cotton swab or
eraser crumbs inside the compartment.

Contact springs

Battery Status LED Indicator

Alkaline, lithium or rechargeable batteries can be used to power the transmit­ter. The type of batteries in use are selectable in a menu on the LCD.

When alkaline or lithium batteries are being used, the LED labeled BATT on
the keypad glows green when the batteries are good. The color changes to red
when the they are nearing the end of life. When the LED begins to blink red,
there will be only a few minutes remaining.

The Power/Function LED on the top panel will mirror the keypad LED unless
the programmable switch is set to Mute, and the switch is turned on.

The exact point at which the LEDs turn red will vary with battery brand and
condition, temperature and power consumption. The LEDs are intended to
simply catch your attention, not to be an exact indicator of remaining time.

A weak battery will sometimes cause the Power LED to glow green immedi­ately after the transmitter is turned on, but it will soon discharge to the point
where it will turn red or the unit will turn off completely.

Rechargeable batteries give little or no warning when they are depleted. If
you wish to use these batteries in the transmitter, the most accurate way to
determine runtime status is by testing the time provided by a particular bat­tery brand and type, then using the BatTime function to determine remaining
runtime.

NOTE: Refer to the Main Menu and Setup Section for BatTime details.

www.lectrosonics.com 5

Operating Instructions

Powering On in Operating Mode

Press and hold the Power Button until a status bar on the LCD is completed.

Hold

DBu

DBu

for
Rf On

V1.13
/1.05

When you release the button, the unit will be operational with the RF output
turned on and the Main Window displayed.

470.100

-40

-20

+0

Powering On in Standby Mode

A brief press of the Power Button , and releasing it before status bar has
completed, will turn the unit on with the RF output turned off. In this Standby
Mode the menus can be browsed to make settings and adjustments without
the risk of interfering with other wireless systems nearby.

Hold
for
Rf On

After settings and adjustments are made, press the power button again to turn
the unit off.

Release Power

Button before
the status bar

has completed

to enter standby

mode

RF indicator blinks

DBu

470.100

-40

-20

+0

Powering Off

Powering
O . . .

From any screen, power can be turned off by selecting
Pwr Off in the power menu, holding the Power Button
in and waiting for the status bar to complete, or with the
programmable switch (if it is configured for this function).

If the power button is released, or the top panel switch is
turned back on again before the status bar is completed,
the unit will remain turned on and the LCD will return to
the same screen or menu that was displayed previously.

NOTE: If the programmable switch is in the OFF position, power can
still be turned on with the power button. If the programmable switch is
then turned on, a brief message will appear on the LCD.

LECTROSONICS, INC.6

Power Menu Options

Entering the Power Menu

With the unit turned on, press the power button once briefly from any menu
or screen and a menu will appear with several options. Use the
row buttons to highlight menu items. Then press MENU/SEL to execute the
item or enter a setup screen. The following options are available:

• Resume - returns to the previous mode and screen

• Pwr Off - turns the unit off irrevocably

• Rf On? - enters a screen to enable the operating or standby modes

• AutoOn? - allows the unit to automatically turn back on after a power
failure or when fresh batteries are installed (works in the operating mode
only)

• Backlit - adjusts the duration of the LCD back light to 5 seconds or 30
seconds, or to remain on

• About - displays model number and firmware
version

and ar-

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LCD Menu Map

Use arrow buttons

Gain

Gain

SEL

BACK

to select value

22

Level meter at bottom of screen

Freq.

ProgSw

Rolloff

Phase

BatType

TxPower

Remote

Locked?

SEL

SEL

SEL

SEL

SEL

SEL

SEL

SEL

BACK

BACK

BACK

BACK

BACK

BACK

BACK

BACK

Freq.

470.675

ProgSW

Rolloff

50 Hz

Phase

Normal
Invert

BatType

Alk.
Lith.

TxPower

25 mW
50 mW

Remote

Enable
Ignore

Locked?

Yes
No

Press MENU/SEL to highlight MHz or kHz

Select value with arrow buttons

Select option with arrow buttons

Power

(None, TalkBk, Powe r, Mute)

Select value with arrow buttons

(35, 50, 70, 100, 120, 150 Hz)

Select option with arrow buttons

Select option with arrow buttons

Select option with arrow buttons

Select option with arrow buttons

Select option with arrow buttons

NOTE: The settings
will be stored when
the BACK button
is pressed.

Default

KeyType

WipeKey

SendKey

SEL

SEL

SEL

SEL

BACK

BACK

BACK

BACK

Default
Settings

No
Yes

KeyType

Universal

WipeKey?

No
Yes

SendKey

Share

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Select option with arrow buttons

Select option with arrow buttons

(Universal, Shared, Standard or Volatile)

Select option with arrow buttons

(Only available when KeyType is set to
Standard, Shared or Volatile)

MENU

Press to send key

SEL

(Only available when KeyType is set to Shared)

Main Menu and Setup Screen Details

Entering the Main Menu

The LCD and keypad interface makes it easy to browse the menus and make
the selections for the setup you need. When the unit is powered up in either
the operating or the standby mode, press MENU/SEL on the keypad to enter
a menu structure on the LCD. Use the
menu item. Then press the MENU/SEL button to enter the setup screen.

Gain

Gain

Freq.
ProgSw
Rolloff

-40

Main Window Indicators

The Main Window displays programmable switch function, Standby or Operat­ing mode, operating frequency, audio level and battery status.

Programmable

Switch Function

and arrow buttons to select the

The prompt in the upper
right corner may display

25

-20

DBu

MUTE

one or both arrows,
depending upon what
adjustment can be made.
If the changes are locked,
a small padlock symbol

0

will appear.

Operating

mode

Frequency (MHz)

-40

-20

Audio level

Mute function

enabled but

not active

DBu

MUTE

470.100

-40

-20

+0

470.100

When the switch is turned
on, the mute icon appear­ance will change and the
word MUTE will blink at the
bottom of the display. The

-10 LED on the top panel
will also glow solid red.

www.lectrosonics.com 9

DBu

MUTE

470.100

<–MUTE–>

Battery status

+0

If the programmable
switch function is set
for Mute, the Main
Window will indicate
that the function is
enabled.

Main Window will blink

the word MUTE when

the audio is muted

Connecting the Signal Source

Microphones, line level audio sources and instruments can be used with
the transmitter. Refer to the section entitled Input Jack Wiring for Different
Sources for details on the correct wiring for line level sources and micro­phones to take full advantage of the Servo Bias circuitry.

Adjusting the Input Gain

The two bicolor Modulation LEDs on the top panel provide a visual indication
of the audio signal level entering the transmitter. The LEDs will glow either red
or green to indicate modulation levels as shown in the following table.

Signal Level -20 LED -10 LED

Less than -20 dB

-20 dB to -10 dB

-10 dB to +0 dB

+0 dB to +10 dB

Greater than +10 dB

NOTE: Full modulation is achieved at 0 dB, when the “-20” LED first
turns red. The limiter can cleanly handle peaks up to 30 dB above this
point.

It is best to go through the following procedure with the transmitter in the
standby mode so that no audio will enter the sound system or recorder during
adjustment.

1) With fresh batteries in the transmitter, power the unit on in the standby
mode (see previous section Powering On in Standby Mode).

2) Navigate to the Gain setup screen.

Off Off

Green Off

Green Green

Red Green

Red Red

Gain

Freq.

Gain

25

ProgSw
Rolloff

3) Prepare the signal source. Position a microphone the way it will be used
in actual operation and have the user speak or sing at the loudest level
that occur during use, or set the output level of the instrument or audio
device to the maximum level that will be used.

4) Use the and arrow buttons to adjust the gain until the –10 dB glows
green and the –20 dB LED starts to flicker red during the loudest peaks
in the audio.

5) Once the audio gain has been set, the signal can be sent through the
sound system for overall level adjustments, monitor settings, etc.

6) If the audio output level of the receiver is too high or low, use only the
controls on the receiver to make adjustments. Always leave the trans­mitter gain adjustment set according to these instructions, and do not
change it to adjust the audio output level of the receiver.

LECTROSONICS, INC.10

-40

-20

0

Selecting Frequency

The setup screen for frequency selection offers two ways to browse the avail­able frequencies.

Frequency groups are also able to be received via IR (Inrared) port sync.
The group options are set by the receiver, and will show at the bottom of the
screen as No Grp, Grp x, Grp w, Grp v, or Grp u.

Use the MENU/SEL button to toggle between options and UP and DOWN
arrows to adjust.

Gain

Freq

Freq

Freq.

ProgSw
Rolloff

628.200

Grp x

628.200

Grp x

Selecting Programmable Switch Functions

The programmable switch on the top panel can be configured using the menu
to provide several functions:

• (none) - disables the switch

• Mute - mutes the audio when switched on; LCD will blink a message and

-10 LED will glow solid red.

• Power - turns the power on and off

• TalkBk - switches the audio output on the receiver to a different channel
for communication with the production crew. Requires a receiver with this
function enabled.

Gain
Freq.

ProgSw

Rolloff

NOTE: The programmable switch will continue to operate whether or
not keypad changes are locked.

ProgSw

Power

Use the and

arrow buttons to

select the desired

function or disable

the switch

Selecting the Low Frequency Roll-off

The low frequency audio roll-off is adjustable to

Rolloff

70 Hz

www.lectrosonics.com 11

optimize performance for ambient noise conditions
or personal preference.

Low frequency audio content may be desirable or
distracting, so the point at which the roll-off takes
place can be set to 20, 35, 50, 70, 100, 120
or 150 Hz.

Selecting Audio Polarity (Phase)

Audio polarity can be inverted at the transmitter so the audio can be mixed
with other microphones without comb filtering. The polarity can also be in­verted at the receiver outputs.

Phase

Phase

BatType
TxPower
Remote

Normal
Invert

Selecting Battery Type

The voltage drop over the life of different batteries varies by type and brand.
Be sure to set the correct battery type for accurate indications and warnings.
The menu offers alkaline or lithium types.

Phase

BatType

BatType

TxPower
Remote

If you are using rechargeable batteries, it is better to use the timer function
on the receiver to monitor the battery life rather than the indicators on the
transmitter. Rechargeable batteries maintain a fairly constant voltage across
the operating time on each charge and stop working abruptly, so you will have
little or no warning as they reach the end of operation.

Alk.
Lith.

Setting Transmitter Output Power

The output power can be set to 25 mW or 50 mW.

Rolloff

TxPower

Phase
BatType

TxPower

25 mW
50 mW

Remote

Remote control “dweedle” tones from a smart phone can be used to control
the transmitter.

LECTROSONICS, INC.12

Locking/Unlocking Changes to Settings

Changes to the settings can be locked to prevent inadvertent changes being
made.

BatType

Locked?

TxPower
Remote

Locked?

A small padlock symbol will appear on adjustment

screens when changes have been locked.

When changes are locked, several controls and actions can still be used:

• Settings can still be unlocked

• Menus can still be browsed

• Programmable switch still works (Mute and On/Off)

• Power can still be turned off by using the power menu or removing the
batteries.

Ye s
No

Gain

-40

-20

25

0

Restoring Default Settings

This is used to restore the factory settings.

Remote
Locked?

Default

KeyType

Default
settings

No
Ye s

www.lectrosonics.com 13

KeyType

The DBu receives an encryption via the IR port from a key generating re­ceiver. Begin by selecting a key type in the receiver and generating a new key
(key type is labeled KEY POLICY in the DSQD receiver). Set
the matching KEY TYPE in the DBu and transfer the key from the receiver
(SYNC KEY) to the DBu via the IR ports. A confirmation message will display
on the receiver display if the transfer is successful. The
transmitted audio will then be encrypted and can only be listened to if the
receiver has the matching encryption key.

The DBu has three options for encryption keys:

Remote

KeyType

Locked?
Default

Standard

KeyType

• Shared: There are an unlimited number of shared keys available. Once
generated by a receiver and transferred to the DBu, the encryption key
is available to be shared (synced) by the DBu with other transmitters/re­ceivers via the IR port. When a transmitter is set to this key type, a menu
item named SEND KEY is available to transfer the key to another device.

• Universal: This is the most convenient encryption option available. All
encryption-capable Lectrosonics transmitters and receivers contain the
Universal Key. The key does not have to be generated by a receiver. Sim­ply set the DBu and a Lecrosonics receiver to Universal, and the encryp­tion is in place. This allows for convenient encryption amongst multiple
transmitters and receivers, but not as secure as creating a unique key.

• Standard: This is the highest
level of security. The encryption
keys are unique to the receiver
and there are only 256 keys
available to be transferred to a
transmitter. The receiver tracks
the number of keys generated
and the number of times each
key is transferred.

WipeKey

Default
KeyType

WipeKey

SendKey

SendKey

Default
KeyType
WipeKey

SendKey

WipeKey?

No

This menu item is only available if
Key Type is set to Standard or
Shared. Select Yes to wipe the
current key and enable the DBu to
receive a new key.

Ye s

This menu item is only

SendKey

Share:

LECTROSONICS, INC.14

available if Key Type is set to
Shared. Press Menu/Sel to
sync the Encryption key to
another transmitter or receiv­er via the IR port.

Whip Antennas

Because the transmitter tunes across such a broad frequency range, it is best
to use the appropriate antenna for maximum operation. Three antennas are
included with the transmitter, and are shipped from the factory pre-cut and
fully assembled. Each antenna covers three blocks. Use the chart below to
determine which antenna best fits your needs.

Frequency Cap
Block Range MHz Color Antenna

470 470.100 - 495.600 Black AMM19

19 486.400 - 511.900 Black AMM19

20 512.000 - 537.500 Black AMM19

21 537.600 - 563.100 Red AMM22

22 563.200 - 588.700 Red AMM22

23 588.800 - 614.300 Red AMM22

Encryption Key and Settings Transfer

A cable between the receiver and the micro USB port on the side of the trans­mitter is used to transfer the encryption key from the receiver to the transmit­ter. This connection can also be used to send the transmitter settings stored in
the receiver to the transmitter.

The interface cable, P/N DRKEYCABLE, is used to make this connection.

NOTE: Reference the DSW System Instruction Manual for instructions
on Encryption Key settings and software.

www.lectrosonics.com 15