HMEC 250 Headset for general aviation Instruction manual
Contents Important safety instructions ...................................................2 Delivery includes ..........................................................................4 The HMEC 250 headset ...............................................................5 Operating elements .....................................................................7 Putting the headset into operation .........................................8 Inserting the batteries ................................................
Important safety instructions • Please read this instruction manual carefully and completely before using the headset. • Make these this instruction manual easily accessible to all users at all times. Always include this instruction manual when passing the headset on to third parties. • During flight operation, do not use the headset for telephone calls. • With the NoiseGard active noise compensation switched on, typical aircraft sounds (for example, those from engines, propellers, warning alarms, etc.
Safety instructions for batteries If abused or misused, batteries may leak and, in extreme cases, may even present an explosion and fire hazard. Sennheiser does not accept any liability for damage arising from abuse or misuse. Keep batteries out of reach of children. Observe correct polarity. Do not heat or throw into fire. Switch off battery powered devices when not in use. Remove batteries when the device is not used for extended periods of time.
Intended use of the headset Intended use includes: • having read this instruction manual, especially the chapter “Important safety instructions” on page 2, • using the headset within the operating conditions and limitations described in this instruction manual. “Improper use” means using the headset other than as described in this instruction manual, or under operating conditions which differ from those described herein.
The HMEC 250 headset The HMEC 250 headset with NoiseGard 2.0 active noise compensation features closed, dynamic, circumaural stereo headphones. The HMEC 250 is a headset for general aviation use. NoiseGard 2.0TM The NoiseGard 2.0 active noise compensation system is based on the principle of cancelling out sound using “antisound” (phase-inverted sound). Tiny microphones pick up low-frequency ambient noise (up to 1 kHz) near the ear. The NoiseGard 2.
Additional features • Outstanding transmission quality for clear communications • Good passive attenuation of ambient noise • Foldable design for space-saving storage and transportation • Noise-compensating boom microphone ensures excellent speech transmission • Flexible microphone boom • Separate left and right channel volume control • Excellent comfort resulting from soft ear pads and headband padding • Audio-input facility for external audio sources, such as mobile phones, MP3 players 6
Operating elements 햴 쐋 Headset Microphone sensitivity control Headset cable Microphone boom Ear pads, ergonomic Headband Battery compartment (on both sides) Operating control integrated in the headset TT VOLUME + button (Talk Through) ON/OFF button (NoiseGard) Operating control integrated in the cable Cable with microphone plug, 5.25 mm jack plug Cable with headphone plug, ¼” (6.35 mm) jack plug 3.
LED indications Meanings of the LED : LED Meaning red NoiseGard is switched on green TalkThrough is switched on flashing Batteries are almost flat Putting the headset into operation Inserting the batteries Insert the batteries into the battery compartments on the left and right ear cups as follows: 왘 Open the battery compartment and open the cover. by pushing the catch 왘 Insert the AAA size battery as shown. 왘 Close the battery compartment .
Connecting a mobile telephone The 2.5 mm jack socket allows you to connect a mobile telephone. For this purpose, the NoiseGard active noise compensation must be switched on and the microphone connector must be connected to the aircraft intercom. A suitable adapter for your mobile telephone with 2.5 mm jack socket is available from your specialist dealer.
Connecting an additional audio player The 3.5 mm jack socket allows you to connect an additional audio player (e.g. MP3 player). DANGER! Danger of accident due to reduced attention! Listening to music or operating an audio player limits your attention and may cause accidents. 왘 During flight operation, do not use the headset for listening to additional audio sources! Hearing damage due to high volumes! This headset is capable of producing high sound pressure levels.
Adjusting the microphone sensitivity The microphone sensitivity has been factory preset to 80 mV/Pa. To change the input sensitivity of the microphone: 왘 Use a suitable slotted screwdriver. 왘 Turn the microphone sensitivity control as shown. Switching between mono and stereo mode The mono/stereo switch allows you to switch between mono and stereo mode, depending on the intercom system.
Using the headset Attaching the cable clip The cable clip allows you to attach the headset cable to your clothing so that the cable doesn’t hinder or distract you. Guide the headset cable through the cable clip as shown. Attach the cable clip to your clothing. Adjusting the headset Wear the headset so that – the microphone boom is on the left side of the mouth (see right/left labeling on the headband joints) and – the headband runs over the top of your head.
Adjusting the 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. 쐋 Adjusting the volume CAUTION! Hearing damage due to high volume levels! The headset is capable of producing high sound pressure levels. Higher volumes or longer durations can damage your hearing! Adjust the volume to a medium level. Make sure that you can hear critical environmental sounds and warning alarms.
Switching the TalkThrough function on/off The HMEC 250 provides excellent attenuation of ambient noise. In order to allow you to communicate undisturbed with the people around you while wearing the headset, the HMEC 250 features a TalkThrough function. Press the TALK THROUGH button to switch the TalkThrough function on or off. When the TalkThrough function is switched on, the LED lights up green.
Switching NoiseGard on/off To switch the NoiseGard active noise compensation on or off: Press the ON/OFF button for approx. one second. When NoiseGard is switched on: – the LED lights up red and – you can listen to music and make telephone calls at the same time. Fail safe operation When the batteries are completely discharged, NoiseGard automatically switches off. RT traffic (e.g. ATC) and intercom will still be heard through the headphones.
Replacing the batteries When the batteries are almost flat, the LED flashes. When the batteries are completely discharged, NoiseGard automatically switches off (fail safe operation). Replace the batteries or the rechargeable batteries as follows: Always replace the two batteries at the same time. Open the battery compartment by pushing the catch and open the cover. Remove the battery. Insert a new AAA size battery as shown. Close the battery compartment .
Folding up the headset For space-saving transportation, the headset can be folded up in different ways: To fold up the headphones as flat as possible: Rotate the ear cups by 90° and turn the microphone boom flat as shown. To fold up the headphones as compact as possible: Fold the ear cups in as shown. For safe transportation of the headset, use the supplied soft case and fold the headset as follows: Rotate the ear cups by 90°. Turn the microphone boom flat as shown.
Care and maintenance CAUTION! Liquids can damage the electronics of the headset! Liquids entering the housing of the headset can cause a short-circuit and damage the electronics. Only use a soft, slightly damp cloth to clean the headset. Do not use any solvents or cleansing agents. Use a soft, slightly damp cloth to clean the headset from time to time. Replacing the ear pads You can replace the ear pads. Spare ear pads are available as accessories.
Attach the ear pad so that the side with the thicker padding points downwards as shown. Press the new ear pad onto the ear cup until it clicks audibly into place. Repeat for the other ear cup. Replacing the wind shield You can replace the wind shield. The HMEC 250 is supplied with a spare wind shield. Carefully pull the wind shield from the microphone. Slide-on the new wind shield and ensure that it fits securely over the microphone.
Specifications General data Weight without cable and without batteries approx. 285 g Temperature range (operation) −10 to +55°C Temperature range (storage) −55 to +55°C Power supply for NoiseGard 2 x 1.5 V AAA size battery or 2 x 1.2 V AAA size rechargeable battery Operating time approx. 30 hours Cable length 1.85 m Headphone connector ¼” (6.35 mm) jack plug Microphone connector 5.
Frequency response (headphones) 8–28,000 Hz Frequency response (TalkThrough) 300–5,000 Hz Nominal impedance passive 150 Ω mono/300 Ω stereo Nominal impedance active 600 Ω mono/1.200 Ω stereo Sound pressure level passive 98 dB at 1 kHz, 1 V active 100 dB at 1 kHz, 1 V THD at 94 dB SPL <1% Noise attenuation 13–34 dB passive attenuation, plus 16–25 dB active noise compensation at low frequencies Contact pressure approx. 8 N Microphone incl.
Manufacturer declarations Warranty Sennheiser electronic GmbH & Co. KG gives a warranty of 36 months on this product. For the current warranty conditions, please visit our website at www.sennheiser.com or contact your Sennheiser partner. CE Declaration of Conformity This equipment is in compliance with the essential requirements and other relevant provisions of Directive 2004/108/EC. The declaration is available at www.sennheiser.com.
Sennheiser electronic GmbH & Co. KG Am Labor 1, 30900 Wedemark, Germany www.sennheiser.com Printed in China, Publ.
