Detailed instructions for use are in the User's Guide.
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Replacing the wind screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Replacing the ear cushions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Connector assignment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 In case of difficulty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] 17 Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Manufacturer declarations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
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The HME 25-1, HME 105, HME 110, HME 120 and HMD 120 are pilot headsets with closed ear protector headphones for use in helicopters, propeller and turboprop aircraft.
Safety requirements
When using a headset, typical aircraft sounds (for example, those from engines, propellers, warning alarms, etc. ) may sound different to you. Before operating any aircraft, make sure that, while wearing a headset, 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. 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. For information on how to clean the headset, contact your Sennheiser agent.
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Headset features
HME 25-1 headset New passive headset with excellent noise attenuation Excellent comfort due to very low weight, soft ear cushions STANDARD 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 (sensitivity adjustment must be carried out by authorized personnel) 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 JTSO approval Made in Germany, five-year warranty
Personalization of the headset Name:
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Product variants
HME 105 headset The HME 105 differs from the HME 25-1 in the following features: No Mono/Stereo switch Connection of headphones and microphone via XLR-5 plug Headset HME 110 The HME 110 differs from the HME 25-1 in the following features: black caps soft earpads LUXURY headband with soft headcushion HME 120 headset The HME 120 differs from the HME 25-1 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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HMD 120 headset The HMD 120 differs from the HME 25-1 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
HME 25-1, HME 105, HME 110 and HME 120 headsets Headset Padded carry and storage bag for headset and accessories Wind screen for microphone Cable clip HMD 120 headset Headset Padded carry and storage bag for headset and accessories Cable clip Recommended Accessories Replaceable gel ear cushions GOP
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Preparing the headsets for use
Connecting the headsets
HME 25-1, HME 110 headset 1 1/4" (6. 35 mm) stereo jack plug for connecting the headphones 1 PJ-068 jack plug for connecting the microphone
Connecting cable for HME 25-1, HME 110
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. HME 105 headset 1 XLR-5 plug for connecting the headphones and the microphone Connect the XLR-5 plug for the headphones and the microphone to the XLR-5 socket of your intercom.
Connecting cable for HME 105
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HME 120 and HMD 120 headsets 1 U-174/U jack plug for connecting the headphones and the microphone Connect the U-174/U jack plug for the headphones and the microphone to the U-174/U socket of your intercom.
Connecting cable for HME 120 and HMD 120
Adjusting the headband
For good noise attenuation and best possible comfort, the headband has to be adjusted to properly fit your head: 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. Press the new earpad onto the earcup until it clicks audibly into place. Repeat for the other earcup.
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Connector assignment
U174/U jack plug 1 Microphone Lo 2 Audio Hi 3 Microphone Hi 4 Audio Lo
XLR-5 connector 1 Audio Hi 2 Audio Lo 3 Microphone Hi 4 Microphone Lo 5--
1/4" (6. 35 mm) stereo jack plug 1 Audio Hi left 2 Audio Hi right 3 Audio Lo
PJ-068 jack plug 1 Not assigned!2 Microphone Hi 3 Microphone Lo
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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 Communications in one ear only (HME 25-1, HME 110) Possible cause and what to do You are using a stereo intercom system but the headset is set to mono operation. You are receiving a mono source but the headset is set to stereo operation. Reduced intelligibility The microphone connection has been pulled out. Microphone output voltage too high or Re-adjust the output voltage on the microphone. too low To do so, use a small slotted screwdriver and turn the `Mic Gain Adjustment' screw (see illustration on page 14) until you have reached the desired setting.
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Technical data
Headphones HME 25-1, HME 110
Transducer principle Ear coupling Frequency response Nominal impedance Attenuation Contact pressure dynamic circumaural, closed 45 15, 000 Hz 150 , mono, 300 , stereo > 10 40 dB approx. 10 N
HME 105, HME 120
dynamic circumaural, closed 45 15, 000 Hz 150 , mono > 10 40 dB approx. 10 N
HMD 120
dynamic circumaural, closed 45 15, 000 Hz 16 , mono > 10 40 dB approx. [. . . ] 10 N
HMD 120
dynamic circumaural, closed 45 15, 000 Hz 16 , mono > 10 40 dB approx. preamplifier (not HMD 120) HME 25-1, HME 110
Transducer principle electret mic capsule, noise-compensated MKE 45-1 300 5, 000 Hz 120 dB 150
HME 105
electret mic capsule, noise-compensated MKE 45-1 300 5, 000 Hz 120 dB 150
HME 120
electret mic capsule, noise-compensated MKE 45-1 300 5, 000 Hz 120 dB 150
HMD 120
dynamic, M-87/AIC 500 4, 000 Hz 1, 8 4 V/74 dB at 5 -
Frequency response Sensitivity Max. terminating impedance
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HME 25-1, HME 110
Output voltage 400 mV ± 3dB at 114 dB (nach RTCA/DO 214) typ. 825 mA as per RTCA/DO 214)
HME 105
400 mV ± 3dB at 114 dB (nach RTCA/DO 214) typ. [. . . ]