Sony MDR-NC40 - Noise Canceling Headphones Manual

Sony MDR-NC40 - Noise Canceling Headphones Manual

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Sony MDR-NC40 - Noise Canceling Headphones Manual

Safety information

Before operating the unit, please read this manual thoroughly and retain it for future reference.

To reduce the risk of fire or electric shock, do not expose this apparatus to rain or moisture.
To reduce the risk of electrical shock, do not open the cabinet. Refer servicing to qualified personnel only.

You are cautioned that any changes or modifications not expressly approved in this manual could void your authority to operate this equipment.

The validity of the CE marking is restricted to only those countries where it is legally enforced, mainly in the countries EEA (European Economic Area).


  • Noise canceling headphones reduce unwanted ambient noise and provide a quieter environment to enhance your listening experience. Ambient sound is reduced by synthesizing with a sound in opposite phase produced by the noise canceling circuit.
  • Lightweight design for long lasting wearing comfort.
  • Super compact foldable design for carrying and storing.
  • Soft and comfortable fit from pressure-relieving urethane ear cushion.
  • Built-in monitor function to hear surrounding sound.
  • Supplied plug adaptor for easy connectivity to stereo mini or dual jacks for in-flight music services.
  • Operates as passive headphones when noise canceling circuit is not activated.

Installing a battery

  1. Push and slide the compartment lid on the rear of the battery box fully, and open. Before opening the compartment lid, check that the claws of the lid are seen.
    Installing a battery Step 1
  2. Insert one R03 (size AAA) battery, matching the on the battery to the in the battery compartment.
    Installing a battery Step 2
  3. Close the lid.
    Installing a battery Step 3

Battery life

Battery Approx. hours* 1
Sony alkaline battery LR03/AM-4 (N) 40 hours* 2
Sony battery R03/UM-4 (NU) 20 hours* 2

* 1 1 kHz, 0.1 mW + 0.1 mW output
* 2 Time stated above may vary, depending on the temperature or conditions of use.

Because the supplied battery was included in the package from the time of manufacture (as a convenience to the user), it is possible that the battery life may be somewhat depleted by the time of purchase. The actual life of the supplied battery may be shorter than the standard time described in this manual when using a fresh battery.

When the battery is low
Power indicator dims, and the noise canceling function is deactivated. Replace the battery with a new one in this case.

Unfolding the headphones

Unfolding the headphones

Storing the headphones in the carrying case

When storing the headphones in the supplied carrying case, set the inner partition up, fold the headphones and store.
The plug adaptor and reserve battery can also be stored in the pockets of the carrying case.
Storing the headphones in the carrying case

Listening to music

  1. Connect the headphones to the AV equipment.
    Listening to music Step 1
  2. Wear the headphones marked R in your right ear and the one marked L in your left ear.
    Listening to music Step 2
  3. Turn on the power of the headphones. The power indicator lights in red. The power switch is located on the battery box. When power is turned on, ambient noise is reduced, and you can listen to music more clearly at a lower volume.
    Listening to music Step 3
  4. Start playing on the AV equipment.

To hear ambient sound for safety

When the power switch is set to on, noise canceling can be deactivated while the MONITOR button is pressed so that you can hear ambient sound.
To hear ambient sound for safety

When using in an airplane

  • The supplied plug adaptor can be connected to the dual or stereo mini jacks in an airplane.
    When using in an airplane
  • Do not use the headphones when use of electronic equipment is prohibited or when use of personal headphones for in-flight music services is prohibited.

If you have any questions or problems concerning the system that are not covered in this manual, please consult the nearest Sony dealer.

After use

Turn off the power of the headphones.


  • The noise canceling function is only effective for noise in the low frequency band. Although noise is reduced, it is not canceled completely.
  • Do not cover the microphone of the headphones with your hands. The noise canceling function may not work properly.
    After use
  • The noise canceling function may not work properly unless the headphones are put on firmly.
  • You can use the headphones even without turning on the power. In this case, the noise canceling function is not active, and the headphones operate as passive headphones.
  • After you turn on the power of the headphones, you may hear a slight hiss. This is the operating sound of the noise canceling function, not a malfunction.
  • In a quiet place, or depending on certain noises, you may feel that the noise canceling function is not effective, or that noise is accentuated. In this case, turn off the power of the headphones.

Using the clip

You can fasten the battery box by its clip on a shirt pocket.
Using the clip


  • Do not put weight or pressure on the headphones as it may cause the headphones to deform during long storage.
  • The earpads may deteriorate due to long-term storage or use.
  • Be careful not to catch your finger as you fold the headphones.
  • Clean the headphones with a soft dry cloth.
  • Do not leave the jack plug dirty otherwise the sound may be distorted.
  • Be sure to bring the headphones to the Sony dealer when requiring a change of earpads or repair work.
  • Do not leave the headphones in a location subject to direct sunlight, heat or moisture.
  • Do not subject the headphones to excessive shock.
  • Handle the driver units carefully.
  • If you fell drowsy or sick while using these headphones, stop use immediately.
  • Mobile phones may cause noise. Keep the headphones away from mobile phones.
  • If headphone sound is noisy, move the battery box away from sources of interference, such as a radio, etc.

Notes on headphones

Preventing hearing damage
Avoid using headphones at high volume. Hearing experts advise against continuous, loud and extended play. If you experience a ringing in your ears, reduce the volume or discontinue use.

Do not use headphones while driving and cycling, etc.
As headphones reduce outside sounds, they may cause a traffic accident. Also, avoid listening with your headphones in situations where hearing must not be impaired, for example, a railroad crossing, a construction site, etc.


No sound

  • Check the connection of the headphones and the AV equipment.
  • Check that the connected AV equipment is turned on.
  • Turn up the volume of the connected AV equipment.
  • Replace the battery.

Muffled sound

  • Turn down the volume of the connected AV equipment.
  • Replace the battery.
    The sound of the connected source device, such as radio and TV, cannot be heard, or headphone sound is noisy.
  • Move the battery box away from the connected source device.



Type Closed, dynamic
Driver unit 30 mm, dome type (CCAW adopted)
Power handling capacity 50 mW
Impedance 68 Ω at 1 kHz (when the power is on)
30 Ω at 1 kHz (when the power is off)
Sensitivity 102 dB/mW (when the power is on)
100 dB/mW (when the power is off)
Frequency response 14 Hz - 22,000 Hz
Total Noise Suppression Ratio*1 Approx. 10 dB*2
Cord Approx. 1.5 m OFC litz cord
(including battery box)
Power source DC 1.5 V, 1 × R03 (size AAA) battery
Mass Approx. 110 g including battery box, cord, and battery
Approx. 80 g not including battery box, cord, and battery

Supplied accessories
Sony R03 (size AAA) battery (1)
Carrying case (1)
Plug adaptor for in-flight use*3 (single/dual) (1)
Operating Instructions (1)
Card warranty (1)

*1 Under the Sony measurement standard.
*2 Equivalent to approx. 90% reduction of energy of sound compared with not wearing headphones.
*3 May not be compatible with some in-flight music services.

Design and specifications are subject to change without notice.

"WALKMAN" and "WALKMAN" logo are registered trademarks of Sony Corporation.

©2008 Sony Corporation
Printed in Malaysia

Documents / Resources

Download manual

Here you can download full pdf version of manual, it may contain additional safety instructions, warranty information, FCC rules, etc.

Download Sony MDR-NC40 - Noise Canceling Headphones Manual


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