HMEC 350/352/355 355-C/356/372/450 HMDC 372 Instructions for use
Contents Safety tips ..................................................................................................................................................... 3 Headset features ........................................................................................................................................ 4 Product variants .......................................................................................................................................... 5 Delivery includes ......
The HMEC 350, HMEC 352, HMEC 355, HMEC 355-C, HMEC 356, HMEC 372, HMEC 450 and HMDC 372 are pilot headsets with closed ear protector headphones and 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.
Headset features HMEC 350 NoiseGard™ headset 4 • 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 • Improved acoustic properties: The frequency response of the headphones has been optimised in the 1 to 4 kHz region to give significantly increased speech intelligibility over the HMEC 300 series • Excellen
• With the NoiseGard™ active noise compensation turned off, the headset can be used as a conventional headset • 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, 5-year warranty (HMEC 450: 10-year warranty) Product variants HMEC 352 NoiseGard™ headset The HMEC 352
HMEC 355-C NoiseGard™ headset The HMEC 355-C differs from the HMEC 350 in the following features: • No Mono/Stereo switch • Connection of headphones and microphone via XLR-5 plug • Connection of NoiseGard™ electronics via XLR-3 plug HMEC 356 NoiseGard™ headset The HMEC 356 differs from the HMEC 350 in the following features: • Connection of headphones, microphone and NoiseGard™ electronics to the on-board power supply system (12–35 V DC) via 6-pin Redel plug HMEC 372 NoiseGard™ headset The HMEC 372
HMEC 450 NoiseGard™ headset The HMEC 450 differs from the HMEC 350 in the following features: • Stylish silver design • Leatherette ear cushions • Headband padding can be buttoned HMDC 372 NoiseGard™ headset The HMDC 372 differs from the HMEC 350 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 7
Delivery includes HMEC 350, HMEC 355-C, HMEC 372, HMEC 450 and HMDC 372 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 372) • MZQ 2002-1 cable clip (Cat. No.
Recommended accessories Replaceable gel ear cushions (Cat. No. 092807) BP-04 battery pack (Cat. No. 500357) (except for HMEC 352, HMEC 355 and HMEC 356) Battery pack with XLR-3 socket for powering the NoiseGard™ electronics of the HMEC 350, HMEC 355-C, HMEC 372, HMEC 450 and HMDC 372 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.
Connecting the headsets Connecting cables for headsets HMEC 350 and HMEC 450 headsets: 1 ¼” (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 350 and HMEC 450 HMEC 352 headset: 1 ¼” (6.
HMEC 355-C headset: 1 1 XLR-5 plug for connecting the headphones and the microphone XLR-3 plug for connecting the power supply for the NoiseGard™ electronics Connecting cable for HMEC 355-C HMEC 356 headset: 1 6-pin Redel plug for connecting the headphones, the microphone and the power supply for the NoiseGard™ electronics Connecting cable for HMEC 356 HMEC 372 and HMDC 372 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
Connector assignment Redel connector (NoiseGard™) 1 2 3 4 5 6 XLR-3 connector (NoiseGard™) Power supply NoiseGard™ (DC+) 1 Power supply NoiseGard™ (DC+) Audio Lo / DC – 2 Ground Audio Hi left 3 –* Audio Hi right Microphone Hi Microphone Lo ; XLR-5 connector HMEC 355 1 Audio Hi 2 Audio Lo / DC – 3 Microphone Hi 4 Microphone Lo 5 Power supply NoiseGard™ (DC+) HMEC 355-C 1 Audio Hi 2 Audio Lo 3 Microphone Hi 4 Microphone Lo 5 Not assigned! ;;;;;;;;;;;;; ;;;;;;;;;;;;; ; ¼” (6.
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-04 battery pack (accessory, except for HMEC 352, HMEC 355 and HMEC 356) 3. Connection to the cigarette ligther socket (12–35 V DC) via adapter cable (accessory, except for HMEC 352, HMEC 355 and HMEC 356) The supply voltage for the NoiseGard™ system is processed by the in-line electronics in the connecting cable.
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 350, HMEC 355-C, HMEC 372, HMEC 450 and HMDC 372 headsets are supplied with an XLR-3 socket for panel mounting in the aircraft.
HMEC 352 headset: 왘 Connect the ¼” (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 355 headset: 왘 Connect the XLR-5 plug to the aircraft’s XLR-5 socket. HMEC 355-C headset: 왘 Connect the XLR-5 plug for the headphones and the microphone to the aircraft’s XLR-5 socket. 왘 Connect the XLR-3 plug to the XLR-3 socket. HMEC 356 headset: 왘 Connect the 6-pin Redel plug to the corresponding socket in the aircraft.
2. Connecting the headset to the battery pack (except HMEC 352, HMEC 355 and HMEC 356) The NoiseGard™ electronics of the HMEC 350, HMEC 355-C, HMEC 372, HMEC 450 and HMDC 372 headsets can also be powered via the BP-04 battery pack (see “Recommended accessories” on page 9). The battery pack can be operated either on standard or rechargeable batteries (not included in the delivery).
Connecting the headset, turning on the battery pack 왘 Connect the XLR-3 plug of the headset connecting cable to the XLR-3 socket on the connecting cable of the battery pack. 왘 HMEC 350 and HMEC 450 headsets: Connect the ¼” (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 355-C headset: Connect the XLR-5 plug for the headphones and the microphone to the aircraft’s XLR-5 socket.
3.
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: 왘 Wear the headset so that the headband runs over the top of your head. 왘 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.
Positioning the microphone Relocating the microphone boom The microphone boom can be worn on either side of the mouth. 왘 Loosen the quick-fixing device. 왘 Rotate the microphone boom by 180°. 왘 Tighten the quick-fixing device. Positioning the microphone towards the corner of the mouth The HMEC 350, HMEC 352, HMEC 355, HMEC 355-C, HMEC 356, HMEC 372 and HMEC 450 headsets feature a flexible microphone boom. Bend the microphone boom so that the microphone is placed at the corner of the mouth.
For positioning the microphone of the HMDC 372 headset, proceed as follows: 왘 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. 왘 Pull the middle part of the microphone boom towards the mouth so that the distance between microphone and mouth is approx. 2 cm. 왘 Tilt the microphone for final positioning.
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-04 battery pack, set the NoiseGard™ ON/OFF switch to “ON” and use the ON/OFF switch on the battery pack.
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.
Spare parts The following spare parts are available from your Sennheiser agent: • • • • • • • Wind screen for MKE 45-1 Ear cushions for all variants except HMEC 450 Ear cushions for HMEC 450 Soft ear cushions for HMEC 450 Headband padding MZQ 2002-1 cable clip Carry and storage bag with shoulder strap Cat. No. 075823 Cat. No. 077966 Cat. No. 085764 Cat. No. 089382 Cat. No. 086628 Cat. No. 044740 Cat. No.
Replacing the headband padding Replace the headband padding if it is damaged. 왘 Pull the Ziploc type fastening strips of the headband padding apart and remove the worn headband padding. 왘 Put the new headband padding around the headband. 왘 Pull the two edges of the headband padding together so that the fastening strips slightly overlap. 왘 Join the fastening strips. Replacing the headband padding of the HMEC 450 headset Replace the headband padding if it is damaged.
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.
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 is accomplished 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.
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. 왘 Check to see if the ON/OFF switch is set to “ON”. The XLR-3 plug has been pulled out of the power source. 왘 Check to see if the XLR-3 plug is correctly connected to the power source. If aircraft powered: The aircraft fuse is defective.
Problem Possible cause and what to do Active noise compensation but very low volume communication The volume control is set too low. 왘 Check the volume setting of the headset. The headphone connection has been pulled out (except HMEC 355, HMEC 355-C and HMEC 356). 왘 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 355, HMEC 355-C and HMEC 356).
Technical data HMEC 350 HMEC 352 HMEC 356 Headphones Transducer principle dynamic Ear coupling circumaural, closed Frequency response 45–15,000 Hz Nominal impedance active/passive 300/150 Ω, mono 600/300 Ω, stereo Attenuation (active and passive) > 25–40 dB Max. sound pressure level 120 dB (±5 %) Contact pressure approx. 10 N Microphone incl.
HMEC 350 HMEC 352 HMEC 356 HMEC 450 6-pin Redel plug for headphones, microphone and NoiseGard™ 6.35 mm stereo jack plug for headphones, PJ-068 jack plug for microphone, XLR-3 for NoiseGard™ General data Connecting cable 1.5 m, unilateral Weight without cable 370 g Power supply for NoiseGard™ 12–35 V DC Current consumption 27 mA (zero signal current), max. 80 mA Fuse 500 mA thermo fuse Connectors 6.
Technical data HMEC 355 HMEC 355-C HMEC 372 HMDC 372 Headphones Transducer principle dynamic Ear coupling circumaural, closed Frequency response 45–15,000 Hz Nominal impedance active/passive 300/150 Ω, mono Attenuation (active and passive) > 25–40 dB Max. sound pressure level 120 dB (±5 %) Contact pressure approx. 10 N 50/35 Ω, mono Microphone incl.
HMEC 355 HMEC 355-C HMEC 372 HMDC 372 General data coiled cable, unilateral Connecting cable 1.5 m, unilateral Weight without cable 370 g Power supply for NoiseGard™ 12–35 V DC Current consumption 27 mA (zero signal current), max.
Certificate of Conformity Sennheiser electronic GmbH & Co. KG declare that these devices conform to the basic requirements of EEC Directive 89/336/EEC and 73/23/EEC. Guarantee Certificate The guarantee period for this Sennheiser product is 5 years from the date of purchase.
Sennheiser electronic GmbH & Co. KG 30900 Wedemark, Germany Phone +49 (5130) 600 0 Fax +49 (5130) 600 300 www.sennheiser.com Printed in Germany Publ.
