AKG DMS Tetrad User manual

DMSTetrad
USER INSTRUCTIONS
............................
2
Please read the manual before using the equipment!
BEDIENUNGSANLEITUNG .................... 22
Bitte vor Inbetriebnahme des Gerätes lesen!
MODE D’EMPLOI................................. 42
Veuillez lire cette notice avant d’utiliser le système!
MODO DE EMPLEO.............................. 62
¡Sirvase leer el manual antes de utilizar el equipo!

2 DMSTetrad
Table of Contents
1Safety and the environment.......................................................................................3
Safety..........................................................................................................................3
Environment ................................................................................................................3
2Description.................................................................................................................4
Introduction .................................................................................................................4
Scope of delivery..........................................................................................................4
Optional accessories ....................................................................................................4
Receiver DSRTetrad .....................................................................................................4
Front panel ............................................................................................................5
Rear panel.............................................................................................................6
DHTTetrad D5 handheld transmitter ..............................................................................7
Controls.................................................................................................................7
DHTTetrad P5 handheld transmitter...............................................................................8
DPTTetrad bodypack transmitter ...................................................................................9
Controls.................................................................................................................9
Microphones, instrument cable .............................................................................10
3Installation and Connection .....................................................................................11
Attaching antennas ....................................................................................................11
Attaching antennas to the rear panel .....................................................................11
Attaching antennas to the front panel on the rack brackets.....................................11
Positioning the receiver ..............................................................................................11
Rack assembly...........................................................................................................11
Connecting the receiver to the mains voltage...............................................................12
Connecting the audio outputs of the DSRTetrad receiver...............................................12
Connecting the receiver to a balanced input...........................................................12
Connecting the receiver to a speaker.....................................................................12
4Setting up ................................................................................................................13
Setting up the receiver................................................................................................13
Inserting and testing batteries in the handheld transmitter DHTTetrad............................13
Inserting and testing batteries in the pocket transmitter DPTTetrad ...............................13
Identifying the channel and/or appliance......................................................................14
Assign the transmitter to a free channel or change the channel.....................................14
Registering a new transmitter on the receiver ..............................................................14
Setting up the handheld transmitter.............................................................................15
Setting up the pocket transmitter ................................................................................15
Connecting a microphone .....................................................................................15
Connecting an instrument.....................................................................................16
Adjusting the audio level on the receiver......................................................................16
Adjusting the internal interference protection ...............................................................16
Switching off the DMSTetrad system...........................................................................16
5Microphone technique.............................................................................................17
DHTTetrad handheld transmitter..................................................................................17
Working distance and proximity effect ...................................................................17
Angle of incidence................................................................................................17
Feedback.............................................................................................................17
Backing vocals.....................................................................................................17
DPTTetrad bodypack transmitter .................................................................................18
C111 LP ear hook microphone..............................................................................18
Putting on the microphone....................................................................................18
Windshield...........................................................................................................18
Moisture shield ....................................................................................................18
6Cleaning...................................................................................................................19
Cleaning the surfaces.................................................................................................19
Internal windshield of handheld transmitter..................................................................19
7Troubleshooting.......................................................................................................20
8Technical data .........................................................................................................21
Table of Contents

DMSTetrad 3
Safety and the environmen
t
Do not spill any liquids on the equipment.
Do not place any containers containing liquid on the device or the power pack.
The equipment must only be used in dry rooms.
The equipment must only be opened, serviced, and repaired by authorized personnel. The
equipment contains no user-serviceable parts.
Before connecting the equipment to power, check that the AC mains voltage stated on the
supplied AC adapter is identical to the AC mains voltage available where you will use the
equipment.
Only operate the equipment with the supplied AC adapter with a 12 V DC output. Using
adapters with a different output voltage or current type may cause serious damage to the unit.
If any solid object or liquid should get into the equipment, shut down the system immediately.
Disconnect the AC adapter from the power outlet at once and have the equipment checked by
our customer service department.
If the equipment is not going to be used for a long time, disconnect the AC adapter from the
power outlet. Please note that if you turn the equipment off while leaving the AC adapter
plugged in, it is not fully isolated from the power supply.
Do not place the equipment near heat sources such as radiators, heating ducts, amplifiers,
etc. and do not expose it to direct sunlight, excessive dust, moisture, rain, mechanical
vibrations, or shock.
To avoid hum or interference, route all audio lines, particularly those connected to the
microphone inputs, away from power lines of any type. If you use cable ducts, be sure to use
separate ducts for the audio lines.
Clean the equipment with a moistened (not wet) cloth only. Be sure to disconnect the AC
adapter from the power outlet before cleaning the equipment. Never use caustic or scouring
cleaners or cleaning products containing alcohol or solvents since these may damage the
enamel and plastic parts.
Only use the equipment for the applications described in this manual. AKG cannot accept any
liability for damages resulting from improper handling or misuse.
The power supply unit consumes a small amount of electricity even when the unit is switched
off. To save energy, unplug the power supply unit from the socket if you are not going to be
using the unit for some time.
The packaging is recyclable. Dispose of the packaging in an appropriate recycling collection
system.
If you scrap the unit, separate the case, electronics and cables and dispose of all the
components in accordance with the appropriate waste disposal regulations.
1Safety and the environment
Safety
Environment

4 DMSTetrad
Description
Thank you for your decision to buy an AKG product. Please read the user instructions
carefully before using the unit and keep them in a safe place so that you can refer to them in the
future at any time. We wish you a lot of fun and success!
The DMSTetrad is available in 3 sets with receiver DSRTetrad:
DMSTetrad Performer Set DMSTetrad Vocal Set P5 DMSTetrad Vocal Set D5
1 receiver DSRTetrad
1 pocket transmitter DPTTetrad
1 MKG L instrument cable
1 C111 LP ear hook microphone
2 detachable antennas
2 antenna attachment cables
2 size AA batteries
2 rack brackets incl. mounting material
1 mains adapter (EU/UK/US)
1 warranty card
1 quick start guide
1 receiver DSRTetrad
1 handheld transmitter DHTTetrad P5
2 detachable antennas
2 antenna attachment cables
2 size AA batteries
1 stand adapter (SA63 CD)
2 rack brackets incl. mounting material
1 mains adapter (EU/UK/US)
1 warranty card
1 quick start guide
1 receiver DSRTetrad
1 handheld transmitter DHTTetrad P5
2 detachable antennas
2 antenna attachment cables
2 size AA batteries
1 stand adapter (SA63 CD)
2 rack brackets incl. mounting material
1 mains adapter (EU/UK/US)
1 warranty card
1 quick start guide
Check that the packaging contains all of the items listed for your system. If anything is missing,
please contact your AKG dealer.
Optional accessories can be found at www.akg.com. Your dealer will be happy to advise you.
The DSRTetrad is a stationary receiver for up to 4 transmitters of the DMSTetrad system.
The DSRTetrad operates in the 2.4 GHz ISM frequency range. Digital and bidirectional
communication between transmitter and receiver. Uncompressed (24 bit) and encrypted (128 bit
AES) transmission.
NOTE
To ensure error-free operation, please make sure that other devices that operate in the 2.4 GHz
range (e.g. Wi-Fi, Bluetooth, access points) are switched off.
If this is not possible, you can increase the resilience of the system to other 2.4 GHz devices with
the INTERFERENCE PROTECTION switch (11) on the receiver. (Position "MID" or "HIGH")
2Description
Introduction
Scope of delivery
Optional accessories
Receiver DSRTetrad

DMSTetrad 5
Description
Front panel
Figure 1: Front panel controls on the DSRTetrad receiver
NOTE
The controls (2 and 3) as well as the LEDs (4 to 6) are identical for all channels.
1ON/OFF button: If the receiver is turned on and ready for operation, this button is lit green. To
turn off the DMSTetrad system, simply switch off the receiver. Switching off the receiver
switches off all transmitters connected to this receiver.
2VOLUME potentiometer: This potentiometer allows continuous adjustment of the audio
output level on this channel (12). The mixing function means that this potentiometer also
influences the sum output (14) of the DSRTetrad.
3CONNECT: This button has two functions:
Press briefly: Check the transmitter assigned to this channel.
Press and hold (approx. 2 seconds): Assign a transmitter to a free channel or
register a transmitter on this channel.
4BAT LED: This LED lights up when the batteries of the transmitter registered on this channel
are starting to fade. If the LED starts to flash red the batteries will be flat within about one hour.
Replace batteries as soon as possible.
5LINK LED: This LED is green when a registered transmitter on this channel is active and ready
for operation. The LED flashes green during channel identification and channel assignment.
6CLIP LED: This LED is red if the audio level on this channel is too high.
7Detachable antennas: The best transmission and reception performances are achieved
when both antennas are pointing upwards in "normal position" (see image on the cover page).
DSRTetrad
1
2
3
5
4
67

6 DMSTetrad
Description
Rear panel
Figure 2: Rear panel controls on the DSRTetrad receiver
8Antenna connectors: Serve to connect the detachable antennas (7) or external antennas.
9DC IN jack 12 V, 0.5 A: For connecting the provided AC adaptor.
10 Strain relief: For the supply cable of the provided AC adaptor.
11 INTERFERENCE PROTECTION switch: For adjusting the internal interference protection.
12 Channel Out/balanced (x 4): Balanced audio output on 3-pole XLR jack. This output
transmits the audio signal of the respective channel. You can connect the microphone inputs on
a mixer to these outputs, for example.
13 Sum output control to regulate the audio level by +20 dB.
14 MIX OUT/balanced (x 1): Balanced audio output on 3-pole XLR jack. This output transmits
the combined audio signal of all 4 channels and you can connect it directly to an active speaker.
DSRTetrad
8
9
10
11
13 14
12

DMSTetrad 7
Description
The DHTTetrad D5 handheld transmitter operates within the 2.4 GHz ISM frequency range. The
transmitter uses two antennas integrated within the housing.
The capsule in the transmitter is the patented dynamic AKG D5 capsule with its supercardioid
polar pattern. It provides low handling noise sensitivity, high gain before feedback and brilliant
sound quality, as well as a built-in wind and pop filter to reduce wind and breath noise.
Controls
15 Status LED: Indicates the transmitter's
operating status.
LED lit green: The transmitter is
connected to the receiver
LED lit red: From the moment the LED
changes to red, the battery capacity will
provide a maximum of one operating hour.
We recommend replacing the batteries
with new ones as soon as possible.
16 Battery cover: See “Inserting and testing
batteries in the handheld transmitter” (page 13).
17 On/Off button:
On: Power to the transmitter is on. The
transmitter is ready for use as soon as it is
switched on.
Off (Digital Mute): Power to the
transmitter is off.
18 Connect button: This button has two functions:
Press briefly: Check the assigned channel on the receiver
Press and hold down (approximately 2 seconds): Assign a free channel on the
receiver to this transmitter.
17 /18 On/Off / Connect button: Use the On/Off (17) and Connect button (18) to assign this
transmitter to a free channel on the receiver. After two minutes without radio contact to the
receiver, the transmitter switches off automatically.
19 GAIN switch: This slide switch allows you to set the audio input sensitivity of the transmitter
to one of two positions: "HIGH" = high input sensitivity, "LOW" = low input sensitivity.
20 Antenna section: The handheld transmitter has a digital diversity antenna system with two
antennas integrated within the housing.
NOTE
Do not hold the transmitter by the antenna section (20) as this will reduce the transmission range.
DHTTetrad D5 handheld transmitter
Figure 3: Controls on DHTTetrad D5
transmitter
15
18
19
20
16
17

8 DMSTetrad
Description
The DHTTetrad P5 handheld transmitter features a dynamic standard capsule with supercardioid
polar pattern.
The controls are identical with those of the DHTTetrad D5.
DHTTetrad P5 handheld transmitter

DMSTetrad 9
Description
You can use the DPTTetrad bodypack transmitter with both dynamic microphones and
condenser microphones operating on a supply voltage of approx. 4 V. Alternatively you may also
connect an electric guitar, electric bass or keytar.
The DPTTetrad operates within the 2.4 GHz ISM frequency range.
Controls
15 Status LED: Indicates the transmitter's operating
status.
LED lit green: The transmitter is connected to
the receiver
LED lit red: From the moment the LED changes
to red, the battery capacity will provide a
maximum of one operating hour. We
recommend replacing the batteries with new
ones as soon as possible.
17 On/Off button:
On: Power to the transmitter is on. The
transmitter is ready for use as soon as it is
switched on.
Off (Digital Mute): Power to the transmitter is
off.
18 Connect button: This button has two functions:
Press briefly: Check the assigned channel on
the receiver
Press and hold down (approximately 2
seconds): Assign a free channel on the receiver
to this transmitter.
17 /18 On/Off / Connect button: Use the On/Off (17) and Connect button (18) to assign this
transmitter to a free channel on the receiver. After two minutes without radio contact to the
receiver, the transmitter switches off automatically.
21 Audio input is a 3-pin mini-XLR connector. Automatically matches the connector pinout of
the recommended AKG microphones or the MKG L instrument cable.
22 Cover: The sliding cover prevents the transmitter from being switched on/off inadvertently
23 Belt clip: For fixing the bodypack transmitter to your
belt. Attach the bodypack transmitter to a belt or in a
pocket with the battery compartment cover facing away
from the body.
24 Battery compartment cover with integrated
screwdriver. See “Inserting and testing batteries in the
pocket transmitter” (page 13).
25 GAIN control: This rotary control allows you to match
the transmitter input gain to the connected microphone or
instrument.
DPTTetrad bodypack transmitter
Figure 4: Controls on DPTTetrad
transmitter
Figure 5: Attachment of
bodypack transmitter to belt
15
17
18
21
22
23 24
25

10 DMSTetrad
Description
Microphones, instrument cable
The following AKG microphones can easily be connected to the audio input of the DPTTetrad:
C111 LP, CK77 WR-L, HC577 L, CK97
The MKG L instrument cable from AKG allows you to connect an electric guitar, electric bass
or keytar to the bodypack transmitter.
The MKG L instrument cable is included in the DMSTetrad Performer Set and is also available
separately as an accessory.
NOTE
Keep the microphones used at least 10 cm away from the bodypack transmitter to prevent
interference in the microphone capsule from being audible in the audio transfer.

DMSTetrad 11
Installation and Connection
Attaching antennas to the rear panel
1) Screw the enclosed antennas (7) or optional external antennas directly onto the antenna
connections (8) on the receiver's rear panel.
Attaching antennas to the front panel on the rack brackets
1) Unscrew the fixing screws on each of the two side
walls.
2) Secure the rack brackets to the receiver using the
fixing screws.
3) Screw the antenna attachment cables onto the
antenna connections (8) on the rear of the
receiver.
4) Attach the antenna cables using long-nosed pliers or
small flat nose pliers to the openings of the rack
brackets.
5) Screw the enclosed antennas (7) or optional
external antennas onto the front of the antenna
cables.
1) Always position the receiver near to where the action is taking place (e.g. stage).
2) Check that you can see the receiver from where you will be using the transmitter.
Fitting the DSRTetrad in a 19" rack
Install the receiver DSRTetrad in your 19" rack with the
supplied rack brackets, fixing screws and washers -
these are screwed into the side of the receiver.
1) Unscrew the fixing screws on each of the two side
walls.
2) Secure the rack brackets to the receiver using the
fixing screws.
3) Secure the receiver in the rack.
4) Screw the antennas onto the rear panel or - using
the antenna attachment cables - onto the front panel
(see "Attaching antennas" Page 11).
5) If using the enclosed antennas (7), turn both antennas up to "normal position" (see
illustration on the title page) to achieve optimum transmission and reception performance.
Using two receivers with the enclosed detachable antennas in one rack
1) Install the two receivers in the rack with one unit of space between them.
2) Turn both antennas (7) up to "normal position" (see image on the cover page).
3Installation and Connection
Attaching antennas
Figure 6: Attaching antennas to
the front panel
Positioning the receiver
Rack assembly
Figure 7: Fitting the DSRTetrad in
a 19" rack

12 DMSTetrad
Installation and Connection
1) Check that the AC mains voltage stated on the included power supply is identical to the AC
mains voltage available where you will use your system. Using the power supply with a
different AC voltage may cause irreparable damage to the unit.
2) Plug the feeder cable of the included power supply into the DC IN socket (9) (12 V, 0.5 A)
of the receiver.
3) Connect the power supply to a power outlet. Ensure that you are using the correct adapter
for the country you are in!
4) Use the strain relief to avoid pulling out the mains cable accidentally.
Connecting the receiver to a balanced input
1) Turn down the level of the audio output on this channel (12) with the VOLUME
potentiometer (2).
2) Use an XLR cable to connect the BALANCED output (12) of the required channel on the
back of the receiver to the balanced microphone input (XLR socket) on the mixer or
amplifier.
Connecting the receiver to a speaker
Use an XLR cable to connect the sum output (14) of all four channels on the back of the receiver
to an active speaker.
Connecting the receiver to the mains
voltage
Connecting the audio outputs of the
DSRTetrad receiver

DMSTetrad 13
Setting up
Press the On/Off switch (1) to switch the receiver on. This button is illuminated green when the
receiver is ready for use.
1) Unscrew the battery cover (16) from the handheld transmitter.
2) Lift up the two battery compartment covers.
3) Insert the supplied batteries into the battery compartment conforming to the polarity marks.
The transmitter will not function if you insert the batteries the wrong way round.
4) Close the two battery compartment covers.
5) Switch on the transmitter with the On/Off button (17).
If the Status LED (15) flashes green, the batteries are in good condition but there is
no radio contact with the receiver. The transmitter must be connected to the receiver.
If the status LED is lit green, the batteries are in good condition and there is radio
contact between the transmitter and receiver. Speak or sing into the microphone.
If the status LED goes red the batteries are likely to be flat in approx. 1 hour. Replace
with new batteries as soon as possible.
If the status LED does not light up the batteries are flat or possibly incorrectly fitted.
Insert new batteries or insert the existing batteries correctly. Check for the correct
polarity.
6) Screw on the battery cover tightly.
1) Press down on the battery compartment cover (24) at the arrow symbol.
2) Pull the battery compartment cover down and off the transmitter.
3) Insert the supplied batteries into the battery compartment conforming to the polarity marks.
The transmitter will not function if you insert the batteries the wrong way round.
4) Slide the slide cover (22) outward and switch on the transmitter using the On/Off switch
(17).
If the status LED (15) flashes green, the batteries are in good condition but there is
no radio contact with the receiver. The transmitter must be connected to the receiver.
If the status LED is lit green, the batteries are in good condition and there is radio
contact between the transmitter and the receiver.
If the status LED goes red, the batteries are likely to be flat in approx. 1 hour. Replace
batteries as soon as possible.
If the status LED does not light up, the batteries are empty or inserted incorrectly.
Insert new batteries or insert the batteries correctly. Check for the correct polarity!
5) Push the slide cover over the On/Off switch to prevent the transmitter from being switched
on/off inadvertently.
6) To close the battery compartment, slide the battery compartment cover onto the battery
compartment from below until the snap hook engages.
4Setting up
Setting up the receiver
Inserting and testing batteries in the
handheld transmitter DHTTetrad
Inserting and testing batteries in the
pocket transmitter DPTTetrad

14 DMSTetrad
Setting up
The provided transmitter is preconfigured to channel 1 on the receiver.
Use the identification feature to check
the channel on the receiver assigned for a transmitter and
the connected transmitter for a channel on the receiver.
Briefly press Connect (18) on the transmitter or receiver.
The Status LEDs (15) on the same channel of the transmitter and receiver flash
green.
NOTE
This identification feature can also be used during operation without causing any disturbance or
interruption.
The following instructions apply for the assignment of a free channel and for changing a channel.
Actions 3 and 4 can be started from the transmitter and receiver. In this example, they are
started from the receiver.
1) Pull the battery compartment cover (16 / 24) down and off the transmitter.
2) Switch on the transmitter and receiver.
3) Press Connect (3) on a free channel of the receiver and hold down until the Status LED (5)
starts to flash after approximately 2 seconds.
You need to confirm with the transmitter within the next 30 seconds.
4) Hold down Connect (18) on the transmitter until the Status LED (15) lights up green.
The status LEDs on the transmitter (15) and the receiver (5) light up green once
assignment has been successful.
NOTE
The actuated settings are saved. This means that you can simply continue using the DMSTetrad
system with the last-used settings (channel assignments) the next time you switch on.
NOTE
Duplicate channel assignment is not possible with the DMSTetrad system!
This means that you cannot assign two (or more) transmitters to one channel on the receiver.
The LED of the connected transmitter is lit green; the LED of the transmitter that is not connected
flashes green. Please assign a free channel to this transmitter.
Make sure you do not assign the same channel twice!
Start the registration process with the transmitter: Transmitter -> Receiver
1) Pull the battery compartment cover (16 / 24) down and off the transmitter.
2) Switch on the receiver.
3) Press and hold Connect (18) on the transmitter while pressing the On/Off button (17) until
the Status LED (15) starts to flash.
Within the next 30 seconds, the status LED (15) flashes rapidly and you need to
confirm with the receiver.
4) Hold down Connect (3) on a free channel of the receiver until the Status LED (5) lights up
green.
The status LEDs on the transmitter (15) and the receiver (5) light up green after
successful registration.
Identifying the channel and/or appliance
Assign the transmitter to a free channel or
change the channel
Registering a new transmitter on the
receiver

DMSTetrad 15
Setting up
You can also start this process from the receiver: Receiver -> Transmitter
1) Pull the battery compartment cover (16 / 24) down and off the transmitter.
2) Switch on the receiver.
3) Press Connect (3) on a free channel of the receiver and hold down until the Status LED (5)
starts to flash after approximately 2 seconds.
You need to confirm with the transmitter within the next 30 seconds.
4) Press and hold Connect (18) on the transmitter while pressing the On/Off button (17) until
the Status LED (15) lights up green.
The status LEDs on the transmitter (15) and the receiver (5) light up green after
successful registration.
1) Switch on the handheld transmitter using the On/Off button (17).
2) Switch on your PA system or amplifier.
3) Assign the handheld transmitter and receiver to a free channel.
4) Speak or sing into the microphone and watch the CLIP LED (6) on the receiver:
Set the GAIN switch (19) to "HIGH" under normal conditions.
If the CLIP LED lights up frequently or all the time when you sing loudly, the input
sensitivity of the transmitter is too high. Set the GAIN to "LOW".
5) Set the volume of the PA system or amplifier referring to the appropriate instruction manual
or by ear.
NOTE
After two minutes without radio contact with the receiver (receiver is OFF, power failure, outside
range, etc) the connected transmitters switch off automatically.
The pocket transmitter DPTTetrad is designed for use with the recommended AKG microphones.
If you would like to connect microphones from other manufacturers to the DPTTetrad, please
note that you may have to replace the connector plug of your microphone with a 3 pole mini XLR
plug.
Contact assignment of the audio input plug:
Contact 1: Shielding
contact 2: Audio in phase (+)
contact 3: Supply voltage
A positive supply voltage (4 V) is provided on contact 3 for condenser microphones.
ATTENTION
Proper performance of the pocket transmitter DPTTetrad with products from other manufacturers
cannot be guaranteed. Potential damage caused by products from other manufacturers shall be
excluded from the guarantee.
Connecting a microphone
1) Remove the battery compartment cover (24).
2) Plug the mini XLR connector on the cable of your microphone into the audio input socket
(21) on the bodypack transmitter.
3) Slide the slide cover (22) to the rear position and switch on the bodypack transmitter using
the On/Off switch (17).
4) Assign a free channel to the bodypack transmitter and receiver.
5) Speak or sing into the microphone.
6) Use the screwdriver integrated in the battery compartment cover to set the GAIN control
(25) to a position where the CLIP LED (6) on the receiver will flash occasionally.
7) Replace the battery compartment cover on the transmitter.
Setting up the handheld transmitter
Setting up the pocket transmitter

16 DMSTetrad
Setting up
Connecting an instrument
1) Remove the battery compartment cover (24).
2) Plug the jack plug of the MKG L instrument cable into the output jack of your instrument and
the mini XLR connector of the instrument cable into the audio input socket (21) of the
pocket transmitter.
3) Slide the slide cover (22) outward and switch on the pocket transmitter using the On/Off
switch (17).
4) Assign a free channel to the pocket transmitter and receiver.
5) Play your instrument.
6) Adjust the GAIN control (25) with the screwdriver integrated in the battery compartment
cover so that the CLIP LED (6) on the receiver flashes occasionally.
7) Slide the battery compartment cover back onto the transmitter.
8) Attach the pocket transmitter as far away as possible from the instrument. (To the back of
the body)
Use the VOLUME potentiometer (2) to adjust the audio output level on this channel (12).
Connect the sum output (14) of the DSRTetrad to an active loudspeaker. Using the receiver's
integrated mixing function you can adjust the sum output (14) with the volume potentiometers
of the active channels.
In an interference-free environment, set the INTERFERENCE PROTECTION switch (11) on the
back of the receiver to "Low" which guarantees an optimum transmission time.
Another device in the 2.4 GHz ISM frequency range may cause interference. Increase the internal
interference protection by setting the INTERFERENCE PROTECTION switch to "MID" or "HIGH".
It is sufficient to switch off the receiver to switch off the DMSTetrad system. The receiver
switches off all transmitters connected to it.
Adjusting the audio level on the receiver
Adjusting the internal interference
protection
Switching off DMSTetrad System

DMSTetrad 17
Microphone technique
A handheld vocal microphone provides many ways of shaping the sound of your voice as it is
heard over the sound system.
The following sections contain useful hints on how to use your DHTTetrad handheld transmitter
for best results.
Working distance and proximity effect
Basically, your voice will sound bigger and mellower, the closer you hold the microphone to your
lips. Moving away from the microphone will produce a more reverberant, more distant sound as
the microphone will pick more of the room’s reverberation.
You can use this effect to make your voice sound aggressive, neutral, sensual, etc. simply by
altering your distance from the microphone.
The proximity effect is a powerful increase in low frequency response that occurs when a sound
source is close to a microphone (less than 2 inches / 5 cm). It will give your voice a voluminous
and punchy quality.
Angle of incidence
Sing to one side of the microphone or above and across the top of the microphone. This provides
a well-balanced, natural sound.
If you sing directly into the microphone, it will not only pick up excessive breath noise but also
overemphasise "s", "sh", "tch", "p", and "t" sounds.
Feedback
Feedback occurs when part of the sound emitted by the loudspeakers is picked up by the
microphone, amplified and retransmitted to the loudspeakers. As of a certain volume (the
feedback threshold) this signal virtually loops, the system emits beeps and other shrill noises and
can only be controlled again by turning down the volume control.
To avoid this, the microphone of the handheld transmitter DHTTetrad features a capsule with
supercardioid polar pattern.
This means it reacts most sensitively to sound coming from the front (voice), while it hardly reacts
to sound coming from the side or the back (e.g. from monitor loudspeakers).
To ensure a minimum of feedback, place PA loudspeakers in front of the microphones (at the
front edge of the stage).
If you use monitor loudspeakers, never point the microphone directly towards the monitors or the
PA loudspeakers.
Feedback can also be triggered by resonance effects (due to room acoustics) especially in the
lower frequency range (proximity effect). In this case, simply increase the microphone distance
to stop the feedback noise.
Backing vocals
1) Never let more than two people share a microphone.
2) Backing vocalists should not sing at more than 35° to the microphone axis.
The microphone is very insensitive to sounds arriving from the side. If the two vocalists were
to try and sing into the microphone at an angle of more than 35° to the microphone axis, you
would have to turn up the level of the microphone channel high enough to cause a feedback
problem.
5Microphone technique
DHTTetrad handheld transmitter

18 DMSTetrad
Microphone technique
C111 LP ear hook microphone
Putting on the microphone
1) Put the microphone on.
2) Bend the gooseneck so that the microphone sits to one side in front of the corner of your
mouth.
NOTE
If you hear excessive pop noise ("p" and "t" sounds are overemphasised unnaturally), move
the microphone capsule further away from your mouth (back or down).
If the microphone sounds "thin" or flat, move the microphone capsule closer to your mouth.
Find the optimum position during the soundcheck.
Windshield
If (for instance, on an open-air stage) excessive wind or pop noise becomes audible, attach the
supplied foam windshield to the microphone.
1) Slide the windshield onto the microphone capsule.
2) Pull the windshield over the outer end of the microphone capsule.
Moisture shield
A special moisture shield on the microphone capsule makes it harder for moisture and make-up
to penetrate into the microphone.
This prevents the microphone apertures from being clogged by perspiration or make-up, which
would make the sound dull and reduce the sensitivity of the microphone. Therefore, you should
never remove the moisture shield from the microphone.
DPTTetrad bodypack transmitter

DMSTetrad 19
Cleaning
Unplug the power supply unit from the socket.
Clean the surface of the unit with a moistened (not wet) cloth.
ATTENTION
Never use caustic or scouring cleaners or cleaning agents containing alcohol or solvents, since
these may damage the enamel and plastic parts.
1) Unscrew and remove the wire-mesh cap of the handheld transmitter.
2) Take the windshield (foam insert) out of the wire-mesh cap.
3) Wash the windshield in mild soap suds.
4) As soon as the windshield has dried, replace it in the wire-mesh cap and screw the
wire-mesh cap onto the handheld transmitter.
6Cleaning
Cleaning the surfaces
Internal windshield of handheld transmitter

20 DMSTetrad
Troubleshooting
Problem Possible cause Remedy
No radio contact, the status LED (15) on the
transmitter is flashing green.
The connected transmitters switch off
automatically after two minutes without
radio contact with the receiver.
The receiver is switched off, there is a power
failure, the transmitter is out of range, or a
transmitter is not registered.
Set up the receiver. Make sure the transmitter is
in range of the transmitter.
No sound
No sound because dual channel usage is not
permitted. Status LED (15) of the transmitter
flashes green, because another transmitter is
active on the same channel on the receiver.
Channel identification is not possible if
transmitter is not connected.
Switch off the transmitter which is not outputting
an audio signal and assign this transmitter to a
free channel on the receiver.
A
C adapter is not connected to receiver and/or
power outlet.
Connect AC adapter to receiver and/or power
outlet.
Receiver is OFF.
Switch on receiver using the On/Off button (1).
Receiver is not connected to mixer or amplifier.
Connect receiver output to mixer or amplifier
input.
VOLUME potentiometer (2) on receiver is at zero.
Turn up VOLUME potentiometer.
Microphone or instrument is not connected to
bodypack transmitter.
Connect microphone or instrument to audio
input (21) on bodypack transmitter.
Transmitter On/Off switch (17) is set to "OFF" or
"MUTE".
Set transmitter On/Off switch to "ON".
Transmitter batteries are not inserted properly.
Insert batteries conforming to "+" and "-"
marks.
Transmitter batteries are flat.
Replace transmitter batteries.
Transmitter is too far away from the receiver.
Move closer to the receiver.
Obstructions between transmitter and receiver.
Remove obstructions.
No line of sight between transmitter and
receiver.
A
void spots where you cannot see receiver.
Receiver is too close to metal objects.
Remove interfering objects or move receiver
away from them.
Noise, crackling, unwanted signals
A
ntenna is in an unsuitable position.
Move receiver to a different location. The best
transmission and reception performance is
achieved when the antennas (7) are pointing
upwards in the "normal position" (see image on
the cover page).
Interference from other wireless systems, TV,
radio, mobile phone, walkie-talkies, or defective
electrical appliances or installations.
Increase the internal interference protection
by
adjusting the INTERFERENCE PROTECTION
switch to the "MID" or "HIGH" setting.
Switch off interfering appliances within the 2.4
GHz ISM frequency range; switch off defective
appliances; have electrical installations checked.
Distortion
GAIN control (19 / 25) is set too high or too low.
Turn GAIN control up or down until distortion
goes away.
Interference from other wireless systems, TV,
radio, mobile phone, walkie-talkies, or defective
electrical appliances or installations.
Increase the internal error correction by
adjusting the INTERFERENCE PROTECTION
switch to the "MID" or "HIGH" setting.
Switch off interfering appliances within the 2.4
GHz ISM frequency range; switch off defective
appliances; have electrical installations checked.
A
ntenna position.
Move receiver to a different location. If dead
spots persist, mark and avoid them.
7Troubleshooting