Instructions for use
Headset
HMEC 300
HMEC 302
HMEC 305
HMEC 305-C
HMEC 306
HMEC 322
HMEC 400
HMDC 322
™
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The HMEC300, HMEC302, HMEC305,HMEC305-C, HMEC306, HMEC322, HMEC400
and HMDC322 are pilot headsetswith closed earprotectorheadphonesand NoiseGard™
active noise compensation for use in helicopters, propeller and turboprop aircraft.
Safety tips
•
With the NoiseGard™ active noise compensation turned on, typical aircraft sounds
(for example, those from engines, propellers, warning alarms, etc.) may sound
different to you. Before operating any aircraft, make sure that, with NoiseGard™
turned on, you can hear and recognize these sounds. Set the volume to safe levels
that do not interfere with your ability to hear informational sounds and warning
alarms.
•
•
•
Do not attempt to repair the headset yourself. If problems occur, contact your
Sennheiser agent for assistance.
Only replace parts of the headset whose replacement is described in this manual.
All other parts of the headset must be replaced by your Sennheiser agent.
Do not immerse the headset in water! For information on how to clean the headset,
contact your Sennheiser agent.
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Headset features
HMEC 300 NoiseGard™ headset
•
•
•
New active headset with effective attenuation of external noise across the entire
frequency spectrum due to NoiseGard™ active noise compensation
NoiseGard™ active noise compensation provides clear communications even in the
noisiest environment
Excellent comfort due to very low weight, soft ear cushions and padded headband
as well as best possible freedom of movement due to unilateral connecting cable
•
•
•
Foldable headband for easy and space-saving storage
Clear communications due to MKE 45-1 electret microphone with adjustable sensitivity
Microphone can be easily positioned and worn on either left or right side due to
flexible microphone boom with quick-fixing device
•
•
•
•
Optimum radio reception due to headphone systems with wide frequency response
Integrated volume control
Adaption to the aircraft intercom system via Mono/Stereo switch
With the NoiseGard™ active noise compensation turned off, the headset can be
used as a conventional headset
114
•
Power supply for NoiseGard™ is provided via on-board power supply system,
cigarette lighter socket or battery pack
•
•
Fail safe operation in case of power failure
Supply voltage for the NoiseGard™ system is processed by the in-line electronics in
the connecting cable
•
Made in Germany, two-year warranty
Product variants
HMEC 302 NoiseGard™ headset
The HMEC 302 differs from the HMEC 300 in the following features:
•
Connection of microphone and NoiseGard™ electronics via PJ-068 plug
HMEC 305 NoiseGard™ headset
The HMEC 305 differs from the HMEC 300 in the following features:
•
•
No Mono/Stereo switch
Connection of headphones, microphone and NoiseGard™ electronics to the on-board
power supply system (12–35 V DC) via XLR-5 plug
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HMEC 305-C NoiseGard™ headset
The HMEC 305-C differs from the HMEC 300 in the following features:
•
•
No Mono/Stereo switch
Connection of headphones and microphone via XLR-5 plug
HMEC 306 NoiseGard™ headset
The HMEC 306 differs from the HMEC 300 in the following features:
•
Connection of headphones, microphone and NoiseGard™ electronics to the on-board
power supply system (12–35V DC) via 6-pin Redel plug
HMEC 322 NoiseGard™ headset
The HMEC 322 differs from the HMEC 300 in the following features:
•
•
•
No Mono/Stereo switch
Coiled cable
Connection of headphones and microphone via U-174/U jack plug to a high impedance
interface in the helicopter
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HMEC 400 NoiseGard™ headset
The HMEC 400 differs from the HMEC 300 in the following features:
•
•
•
Stylish silver design
Leatherette ear cushions
Headband padding can be buttoned
HMDC 322 NoiseGard™ headset
The HMDC 322 differs from the HMEC 300 in the following features:
•
•
•
•
No Mono/Stereo switch
Coiled cable
M-87/AIC dynamic microphone and low impedance headphones
Connection of headphones and microphone via U-174/U jack plug to a low impedance
interface in the helicopter
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Delivery includes
HMEC 300, HMEC 305-C, HMEC 322, HMEC 400 and HMDC 322 headsets
•
•
•
•
•
Headset
3-pin XLR socket for aircraft panel mounting (power supply via the on-board system)
Padded carry and storage bag with shoulder strap for headset and accessories
Wind screen for microphone (except HMDC 322)
MZQ 2002-1 Cable clip (Cat. No. 44740)
HMEC 302, HMEC 305 and HMEC 306 headsets
•
•
•
•
Headset
Padded carry and storage bag with shoulder strap for headset and accessories
Wind screen for microphone
MZQ 2002-1 Cable clip (Cat. No. 44740)
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Recommended accessories
Replaceable gel ear cushions (Cat. No. 83140)
BP-03 battery pack (except for HMEC 302, HMEC 305 and HMEC 306)
Battery pack with XLR-3 socket for powering the NoiseGard™ electronics of the HMEC 300,
HMEC 305-C, HMEC 322, HMEC 400 and HMDC 322 headsets. Four 1.5 V AA size
alkaline manganese batteries (IEC LR 6) ensure approx. 15 hours of reliable operation
(batteries are not included in the delivery). Length of connecting cable: 0.9 m.
Adapter cables (except for HMEC 302, HMEC 305 and HMEC 306)
Sennheiseroffersspecialadaptercablesforconnecting the NoiseGard™electronicsofthe
HMEC 300, HMEC 305-C, HMEC 322, HMEC 400 and HMDC 322 headsets to the on-
board power supply via the cigarette lighter socket:
ACX-1
ACX-2
•
•
ACX-1 adapter cable for powering one headset via the cigarette lighter socket
ACX-2 adapter cable for powering two headsets via the cigarette lighter socket
The adapter cables are also available with a right-angled jack plug featuring a 7.5 A fuse
and a green LED operation indicator:
•
•
ACX-11 adapter cable for powering one headset via the cigarette lighter socket
ACX-11
ACX-22
ACX-22 adapter cable for powering two headsets via the cigarette lighter socket
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Connecting the headsets
Connecting cables for headsets
HMEC 300 and HMEC 400 headsets:
1
1/4” (6.35 mm) stereo jack plug for connecting the headphones
1 PJ-068 jack plug for connecting the microphone
1 XLR-3 plug for connecting the power supply for the NoiseGard™ electronics
Connecting cable for
HMEC 300 and HMEC 400
HMEC 302 headset:
1 /4” (6.35 mm) stereo jack plug for connecting the headphones
1 PJ-068 jack plug for connecting the microphone and the power supply for the
NoiseGard™ electronics
Connecting cable for
HMEC 302
HMEC 305 headset:
1 XLR-5 plug for connecting the headphones, the microphone and the power supply for
the NoiseGard™ electronics
Connecting cable for
HMEC 305
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HMEC 305-C headset:
1 XLR-5 plug for connecting the headphones and the microphone
1 XLR-3 plug for connecting the power supply for the NoiseGard™ electronics
Connecting cable for
HMEC 305-C
HMEC 306 headset:
1 6-pin Redel plug for connecting the headphones, the microphone and the power
supply for the NoiseGard™ electronics
Connecting cable for
HMEC 306
HMEC 322 and HMDC 322 headsets:
1 U-174/U jack plug for connecting the headphones and the microphone
1 XLR-3 plug for connecting the power supply for the NoiseGard™ electronics
Connecting cable for
HMEC 322 and HMDC 322
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Powering options
There are three options for powering the NoiseGard™ active noise compensation:
1. Connection to the on-board system (12–35 V DC)
2. Connection to the BP-03 battery pack
(accessory, except for HMEC 302, HMEC 305 and HMEC 306)
3. Connection to the cigarette ligther socket (12–35 V DC) via adapter cable
(accessory, except for HMEC 302, HMEC 305 and HMEC 306)
The supply voltage for the NoiseGard™ system is processed by the in-line electronics in
the connecting cable.
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1. Connecting the headset to the on-board system
The NoiseGard™ electronics can be connected to on-board power supply systems with
operating voltages between 12–35 V DC.
Danger of short circuit!
Before turning on NoiseGard™, ensure that the on-board power supply system is
protected by a 1 A fuse.
Power supply for
NoiseGard™
The HMEC 300, HMEC 305-C, HMEC 322, HMEC 400 and HMDC 322 headsets are
supplied with an XLR-3 socket for panel mounting in the aircraft. The XLR-3 socket must
be mounted by a technician qualified to perform this type of installation.
Ground
Do not connect!
XLR-3 socket for HMEC 300, HMEC 305-C,
HMEC 322, HMEC 400 and HMDC 322
headsets
HMEC 300 and HMEC 400 headsets:
Ǡ
Connect the 1/4” (6.35 mm) stereo jack plug for the headphones and the PJ-068 jack
plug for the microphone to the corresponding jack sockets of your intercom.
Ǡ
Connect the XLR-3 plug to the XLR-3 socket.
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Headset HMEC 302:
Ǡ
Connect the 1/4” (6.35 mm) stereo jack plug for the headphones and the PJ-068 jack
plug for the microphone to the corresponding jack sockets of your intercom.
HMEC 305 headset:
Connect the XLR-5 plug to the aircraft’s XLR-5 socket.
Ǡ
Headset HMEC 305-C:
Ǡ
Connect the XLR-5 plug for the headphones and the microphone to the aircraft’s
XLR-5 socket.
Ǡ
Connect the XLR-3 plug to the XLR-3 socket.
HMEC 306 headset:
Connect the 6-pin Redel plug to the corresponding socket in the aircraft.
Ǡ
HMEC 322 and HMDC 322 headsets:
Ǡ
Connect the U-174/U jack plug for the headphones and the microphone to the
U-174/U socket of your intercom.
Ǡ
Connect the XLR-3 plug to the XLR-3 socket.
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2. Connecting the headset to the battery pack
(except HMEC 302, HMEC 305 and HMEC 306)
The NoiseGard™ electronics of the HMEC 300, HMEC 305-C, HMEC 322, HMEC 400 and
HMDC 322 headsets can also be powered via the BP-03 battery pack (ꢀ ‘Recommended
accessories’). The battery pack can be operated either on standard or rechargeable
batteries (not included in the delivery). However, to ensure a longer operating time, we
would recommend using standard AA size alkaline manganese batteries (IEC LR6). If
operated on rechargeable batteries, the operating time will be reduced to approx. 3
hours.
Inserting / replacing the the batteries
Ǡ
Ǡ
Open the cover of the battery compartment.
Insert four AA size alkaline-manganese batteries (IEC LR6). Observe correct polarity
when inserting the batteries.
Ǡ
Close the cover of the battery compartment.
LED operation and battery status indication
The battery pack has two control LEDs.
Green LED:
Red LED:
The battery pack is turned on and the battery capacity is sufficient.
The batteries are low. Replace the batteries.
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Connecting the headset, turning on the battery pack
Ǡ
Connect the XLR-3 plug of the headset connecting cable to the XLR-3 socket on the
connecting cable of the battery pack.
Ǡ
HMEC 300 and HMEC 400 headsets: Connect the 1/4” (6.35 mm) stereo jack plug
forthe headphonesand the PJ-068 jackplug forthe microphone to the corresponding
jack sockets of your intercom.
HMEC 305-C headset: Connect the XLR-5 plug for the headphones and the
microphone to the aircraft’s XLR-5 socket.
HMEC 322 and HMDC 322 headsets: Connect the U-174/U jack plug for the
headphones and the microphone to the U-174/U socket of your intercom.
Ǡ
Turn on the battery pack by setting the ON/OFF switch to ON. The green LED power
indicator lights up.
Note:
When using the battery pack, the ON/OFF switch integrated into the headset
connecting cable is out of operation.
Attaching the battery pack to clothing
The battery pack can be attached to clothing by means of the supplied attachment clip,
Velcro tape is also supplied.
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3. Connecting the headset via a cigarette lighter adapter cable
(except HMEC 302, HMEC 305 and HMEC 306)
Sennheiseroffersspecialadaptercableswith XLR-3 socket forconnecting the NoiseGard™
electronics of the HMEC 300, HMEC 305-C, HMEC 322, HMEC 400 and HMDC 322
headsets to the on-board power supply via the cigarette lighter socket:
•
•
ACX-1 adapter cable for powering one headset via the cigarette lighter socket
ACX-2 adapter cable for powering two headsets via the cigarette lighter socket
ACX-1
ACX-2
The adapter cables are also available with a right-angled jack plug featuring a 7.5 A fuse
and a green LED operation indicator:
•
•
ACX-11 adapter cable for powering one headset via the cigarette lighter socket
ACX-22 adapter cable for powering two headsets via the cigarette lighter socket
ACX-11
ACX-22
Connecting the headset
Ǡ
Connect the XLR-3 plug of the headset connecting cable to the XLR-3 socket of the
adapter cable.
Ǡ
Connect the plug or right-angled jack plug ofthe adaptercable to the cigarette lighter
socket.
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Preparing the headsets for use
Adjusting the headband
For good noise attenuation and best possible comfort, the headband has to be adjusted
to properly fit your head:
Ǡ
Ǡ
Wear the headset so that the headband runs over the top of your head.
Adjust the length of the headband so that
• your ears are completely inside the ear cushions,
• you feel even, gentle pressure around your ears,
• a snug fit is ensured.
Note:
Make sure not to squeeze any connecting cable when adjusting the headband.
Squeezing can damage the connecting cables.
Ǡ
Ǡ
Turn on the NoiseGard™ active noise compensation by setting the ON/OFF switch
to ON (ꢀ “Turning NoiseGard™ on/off”).
Final adjustment is best made in a noisy environment.
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Positioning the microphone
Relocating the microphone boom
The microphone boom can be worn on either side of the mouth.
Ǡ
Ǡ
Ǡ
Loosen the quick-fixing device.
Rotate the microphone boom by 180°.
Tighten the quick-fixing device.
Positioning the microphone towards the corner of the mouth
The HMEC 300, HMEC 302, HMEC 305, HMEC 305-C, HMEC 306, HMEC 322 and
HMEC 400 headsets feature a flexible microphone boom. Bend the microphone boom so
that the microphone is placed at the corner of the mouth. Maintain a distance of approx.
2 cm between microphone and mouth.
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For positioning the microphone of the HMDC 322 headset, proceed as follows:
Ǡ
Adjust the length of the microphone boom so that the microphone is placed at the
corner of the mouth. To do so, loosen the quick-fixing device and adjust the
microphone boom in length.
Ǡ
Ǡ
Pull the middle part of the microphone boom towards the mouth so that the
distance between microphone and mouth is approx. 2 cm.
Tilt the microphone for final positioning.
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Additional information for helicopter use of the HMEC 322 headset
The polarity of the microphone connection in helicopters is not standardized. If the
microphone of your headset does not work with the existing polarity, you can reverse the
polarity on the headset by simply rotating the microphone module. To do so, please
proceed as follows:
1. Pull the wind screen from the microphone.
2. Loosen the screws by approx. half a turn.
3. Pull the microphone module from the boom-arm.
4. Rotate the microphone module by 180°.
5. Put the rotated microphone module back into the boom-arm.
6. Now tighten the screws from the other side.
7. Slide the windscreen over the microphone.
Rotating the microphone module does not change its acoustic properties. Due to its noise-
compensating pick-up pattern, the microphone can be used from either side.
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Using the headsets
Turning NoiseGard™ on/off
With the NoiseGard™ active noise compensation turned off, the headset can be used as
a conventional headset.
Turn on the NoiseGard™ active noise compensation by setting the ON/OFF switch to ON.
When using the BP-03 battery pack, set the NoiseGard™ ON/OFF switch to ON and use
the ON/OFF switch on the battery pack.
Mono/Stereo selection (except HMEC 305, HMEC 305-C, HMEC 322 and
HMDC 322)
In general, you’ll receive a mono sound source so that the Mono/Stereo switch can remain
set to “Mono”. When using a stereo intercom system, set the Mono/Stereo switch to
“Stereo”.
Adjusting the volume
Exposure to loud sounds can cause hearing damage!
Set the volume control to a medium value. Make sure that you can hear critical sounds
such as warning alarms.
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Mic Gain Adjustment
Adjusting the microphone gain
According to JTSO approval C58a, the microphone output voltage has to be factory-
preset to 400 mV. If this output voltage is too high or too low for your intercom system,
it can easily be re-adjusted on the microphone. To do so, use a small slotted screwdriver
and turn the ”Mic Gain Adjustment” screw (see illustration on the left) until you reach the
desired setting.
Attaching the cable clip
The headphone cable can be fixed by means of the cable clip. Guide the headphone cable
through the metal cable clip as shown in the illustration on the left. Attach the cable clip
to your clothing and then loop the cable through the clip so that the headphone cable
doesn‘t disturb you.
Folding up the headphones
For easy and space-saving transportation, the earcups can be folded up and tucked
between the headband.
Unfold the headphones by grasping both earcups and pulling them down and away from
the headband.
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Spare parts
The following spare parts are available from your Sennheiser agent:
•
•
•
•
•
Wind screen for MKE 45-1 electret microphone
Ear cushions
Headband padding
Cable clip
Carry and storage bag with shoulder strap
Replacing the wind screen
If the wind screen for the electret microphone shows signs of wear such as tears or holes,
replace the wind screen. Pull the wind screen from the microphone. Gently slide-on the
new wind screen and ensure that it fits securely over the microphone.
Replacing the ear cushions
Replace the ear cushions if they are damaged. Grasp behind the ear cushions and pull
them up and away from the earcups. Slide the new ear cushions onto the earcups.
For best results replace the ear cushions after 100 hours of use or two years.
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Replacing the headband padding
Replace the headband padding if it is damaged.
Ǡ
Pull the Ziploc type fastening strips of the headband padding apart and remove the
worn headband padding.
Ǡ
Ǡ
Put the new headband padding around the headband.
Pull the two edges of the headband padding together so that the fastening strips
slightly overlap.
Ǡ
Join the fastening strips.
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In case of difficulty
If problems occur that are not listed in the below table, please contact your Sennheiser
agent.
Problem
Possible cause and what to do
Clear communication but no
active noise compensation
The NoiseGard™ electronics are turned off.
Ǡ
Check to see if the ON/OFF switch is set to ON.
The XLR-3 plug has been pulled out of the power source.
Check to see if the XLR-3 plug is correctly connected to the power source.
If aircraft powered: The aircraft fuse is defective.
Check the aircraft fuse.
If battery powered (except HMEC 302, HMEC 305 and HMEC 306): The batteries are low.
Ǡ
Ǡ
Ǡ
Check to see if the green LED on the battery pack is lit. If the red LED is lit, replace
the batteries.
136
Problem
Possible cause and what to do
Active noise compensation but
very low volume communication
The volume control is set too low.
Ǡ
Check the volume setting of the headset.
The headphone connection has been pulled out (except HMEC 305, HMEC 305-C and
HMEC 306).
Ǡ
Check to see if the headphone jack plug is correctly connected.
Active noise compensation but
reduced intelligibility
The microphone connection has been pulled out (except HMEC 305, HMEC 305-C and
HMEC 306).
Ǡ
Check to see if the microphone jack plug is correctly connected.
You are using a stereo intercom system but the headset is set to mono operation.
Set the Mono/Stereo switch to ‘Stereo’.
You are receiving a mono source but the headset is set to stereo operation.
Set the Mono/Stereo switch to ‘Mono’.
Communications in one ear only
(only HMEC 300, HMEC 302,
HMEC 306 and HMEC 306)
Ǡ
Ǡ
Re-adjust the output voltage on the microphone.
Microphone output voltage set
too high or too low
Ǡ
To do so, use a small slotted screwdriver and turn the “Mic Gain Adjustment” screw
(see illustration on page 133) until you reach the desired setting.
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Valuable information on NoiseGard™
The NoiseGard™ principle
One of the greatest stress factors today is noise. Research has shown that noise affects
the nervous system, and can cause tiredness, poor concentration, irritability and tension.
Of even greater concern is the permanent damage to hearing that can result from noise
at high levels.
This problem concerns pilots in particular. Cockpit noise amounts to about 80 dB(A) in jets
and to 90 up to 97 dB(A) in turboprops. During takeoff and landing, the noise level is even
higher. To be able to understand radio traffic in spite of the noisy environment, the ATC
signal level must be set to at least 95 dB(A). Permanent hearing loss caused by the
continuous noise in aircrafts is the reason why many pilots became prematurely disabled
or lost their pilot´s license.
Circumaural communication headsets provide noise attenuating properties and are
commonly used to address this problem. However, the noise attenuation of these
headsets is uneven. High frequencies are reduced considerably, but low frequency wind
and engine noise, the most prominent noise in manyoftoday'saircrafts, isattenuated very
little.
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In response to these problems, Sennheiser has developed an active noise compensation
system – NoiseGard™ – which, combined with a high-quality passive hearing protector,
provides consistent noise attenuation over the entire audio range. The overall noise level
is reduced so that the radio volume can be turned down but enough noise still remains
for the pilot to safely monitor the aircraft engines.
A
NoiseGard™ active noise compensation is achieved by generating a signal identical in
sound pressure level but exactly reversed in phase to the noise signal, the effect being that
the out-of-phase signal cancels most of the noise signal.
Active noise compensation isaccomplished in the following manner:Each earcup includes
a microphone, a feedback control circuit, and a transducer to reproduce both the
communication and the noise cancelling signal. The feedback control microphones sense
the total sound pressure within each earcup resulting from both the desired radio signal
from the receiver and the undesired noise that has come through the earcup. The
microphone signal is amplified and the radio signal is subtracted from it. The remaining
signal (noise) is then filtered and inverted and the radio signal is added back in. Eventually,
the entire signal is amplified and fed back to the transducer in each earcup. Since the noise
component ofthe signalisinverted, it cancelsthe noise signalcoming through the earcup.
The radio signal remains unaffected, as it was not processed through the cancellation
circuits.
139
The above diagram shows noise compensation with NoiseGard™: Passive hearing
protectors effectively attenuate noise from the middle and upper frequency range, the
effect decreasing sharply in the lower range. However, active noise compensation with
NoiseGard™ combined with passive hearing protectors results in a reduction of noise of
approx. 25 dB in the 25–500 Hz frequency range. The total attenuation resulting from
active and passive noise compensation is about 30 dB over the entire audio range.
A 10 dB reduction in noise is perceived subjectively as a halving in volume. A further
reduction in noise of 10 dB again results in a decrease in unwanted noise by 50 % .
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Connector assignment
6
3
2
4
1
5
solder side
XLR-5 connector
Redel connector (NoiseGard™)
XLR-3 connector (NoiseGard™)
HMEC 305
HMEC 305-C
1 PowersupplyNoiseGard™(DC+) 1 Power supply NoiseGard™ (DC+) 1 Audio Hi
1 Audio Hi
2 Audio Lo / DC –
3 Audio Hi left
4 Audio Hi right
5 Microphone Hi
6 Microphone Lo
2 Ground
3 Do not connect!
2 Audio Lo / DC –
3 Microphone Hi
4 Microphone Lo
2 Audio Lo
3 Microphone Hi
4 Microphone Lo
5 Power supply NoiseGard™ (DC+) 5 Not assigned!
1
2
3
1
2
3
1
2 3
4
1/4” (6.35 mm) stereo jack plug
U174/U jack plug
PJ-068 jack plug
HMEC 302
HMEC 300
1 Audio Hi left
2 Audio Hi right
3 Audio Lo
1 Microphone Lo
2 Audio Hi
3 Microphone Hi
4 Audio Lo
1 PowersupplyNoiseGard™(DC+) 1 Not assigned!
2 Microphone Hi
3 Microphone Lo / DC –
2 Microphone Hi
3 Microphone Lo
141
Technical data
HMEC 300
HMEC 302
HMEC 306
HMEC 400
Headphones
Transducer principle
dynamic
Ear coupling
Frequency response
Nominal impedance active/passive
circumaural, closed
45–15,000 Hz
300/150 Ω, mono
600/300 Ω, stereo
> 25 – 40 dB
Attenuation (active and passive)
Max. sound pressure level
Contact pressure
120 dB (± 5% )
approx. 10 N
Microphone incl. preamplifier
Transducer principle
Frequency response
Sensitivity
electret mic capsule, noise-compensated, MKE 45-1
300–5,000 Hz
–
Max. sound pressure level
Min. terminating impedance
Output voltage
120 dB
150 Ω
400 mV ± 3 dB at 114 dB (as per RTCA/DO 214)
Supply voltage
typ. 16 V DC (8 – 16 V DC, approx. 8 – 25 mA, as per RTCA/DO 214)
142
HMEC 300
HMEC 302
HMEC 306
HMEC 400
General data
Connecting cable
Weight without cable
Power supply for NoiseGard™
Current consumption
Fuse
1.5 m, unilateral
370 g
12–35 V DC
27 mA (zero signal current), max. 80 mA
500 mA thermo fuse
Connectors
6.35 mm stereo jack plug 6.35 mm stereo jack plug 6-pin Redel plug for
6.35 mm stereo jack plug
for headphones,
PJ-068 jack plug for
mirophone,
XLR-3 for NoiseGard™
Mono/Stereo switch
for headphones,
PJ-068 jack plug for
microphone and
NoiseGard™
headphones, microphone for headphones,
and NoiseGard™
PJ-068 jack plug for
mirophone,
XLR-3 for NoiseGard™
Controls
On/off switch for NoiseGard™
Volume control for headphones
Temperature range
Operation
Storage
–15°C ... + 55°C
–55°C ... + 55°C
Operating time Battery pack
with batteries (four 1.5 V AA size alkaline-manganese batteries): approx. 15 hours
with rechargeable batteries: approx. 3 hours
143
Technical data
HMEC 305
ȊHMEC 305-C
ȊHMEC 322
ȊHMDC 322
Headphones
Transducer principle
dynamic
Ear coupling
Frequency response
Nominal impedance active/passive
Attenuation (active and passive)
Max. sound pressure level
Contact pressure
circumaural, closed
45–15,000 Hz
300/150 Ω, mono
> 25 – 40 dB
120 dB (± 5% )
approx. 10 N
Ȋ 50/35 Ω, mono
Microphone incl. preamplifier
Transducer principle
electret mic capsule,
noise-compensated,
MKE 45-1
Ȋ dynamic mic capsule,
Ȋ noise-compensated,
Ȋ M-87/AIC
Frequency response
Sensitivity
300–5,000 Hz
–
Ȋ 500–4,000 Hz
Ȋ 1.8–4 µV / 74 dB at 5 Ω
Max. sound pressure level
Min. terminating impedance
Output voltage
120 dB
150 Ω
Ȋ –
Ȋ –
Ȋ –
Ȋ –
400 mV ± 3 dB at 114 dB (as per RTCA/DO 214)
typ. 16 V DC (8 – 16 V DC, approx. 8 – 25 mA, as per RTCA/DO 214)
Supply voltage
144
HMEC 305
ȊHMEC 305-C
ȊHMEC 322
ȊHMDC 322
General data
Connecting cable
Weight without cable
Power supply for NoiseGard™
Current consumption
Fuse
1.5 m, unilateral
370 g
12–35 V DC
27 mA (zero signal current), max. 80 mA
500 mA thermo fuse
Ȋ coiled cable, unilateral
Connectors
XLR-5 for headphones,
microphone and
NoiseGard™
Ȋ XLR-5 for headphones Ȋ U-174/U jack plug for headphones and microphone,
Ȋ and microphone.
Ȋ XLR-3 for NoiseGard™
Ȋ XLR-3 for NoiseGard™
Ȋ
Controls
On/off switch for NoiseGard™
Volume control for headphones
Temperature range
Operating time Battery pack
Operation
Storage
–15°C ... + 55°C
–55°C ... + 55°C
with batteries (four 1.5 V AA size alkaline-manganese batteries): approx. 15 hours
with rechargeable batteries: approx. 3 hours
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Certificate of Conformity
Sennheiser electronic GmbH & Co. KG declare that this device conforms to the applicable CE standards and regulations.
Forup-to-date information on Sennheiserproducts, you can also visit the SennheiserWeb site at “http://www.sennheiser.com”.
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