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How to use

Charge the headphones.

Insert the supplied rechargeable battery into the left housing of 
the headphones.

Observe the correct polarity when installing battery.

Connect the A/V component, following hookup 

 or 

 below.

 Using the headphone jack of the A/V component

Headphone 
jack (Stereo 
mini jack)

TV, Digital music player, etc.

Turn on the A/V component.

Wear the headphones.

Before listening

To reduce the risk of hearing damage, first 
lower the volume.

Tactile dot

Checking the included items

RF stereo transmitter 
TMR-RF912R

Wireless stereo headphones 
MDR-RF912R

AC adaptor (1)

Rechargeable nickel-metal 
hydride battery BP-HP550-11 (1)

Adjust the volume.

Tactile dot

If you cannot receive a clear audio signal

First change the radio frequency with the CHANNEL selector switch 
on the transmitter, then change the radio frequency to that of the 
transmitter with the channel switch on the headphones.

English

Wireless Stereo Headphone System

WARNING

To reduce the risk of fire or electric shock, do not 
expose this apparatus to rain or moisture.

To reduce the risk of fire or electric shock, do not expose 
this apparatus to dripping or splashing, and do not place 
objects filled with liquids, such as vases, on the apparatus.

Do not expose the batteries (battery pack or batteries 
installed) to excessive heat such as sunshine, fire or the 
like for a long time.

To avoid electrical shock, do not open the cabinet. Refer 
servicing to qualified personnel only.

Do not install the appliance in a confined space, such as a 
bookcase or built-in cabinet.

The AC Adaptor is not disconnected from the mains as 
long as it is connected to the AC outlet, even if the unit 
itself has been turned off.

As the main plug of AC power adaptor is used to 
disconnect the AC power adaptor from the mains, connect 
it to an easily accessible AC outlet. Should you notice an 
abnormality in it, disconnect it from the AC outlet 
immediately.

Excessive sound pressure from earphones and 
headphones can cause hearing loss.

The nameplate of transmitter is located on the bottom 
exterior.

Information

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

If you have any questions about this product, you may 
call: 
Sony Customer Information Services Center 
1-800-222-7669 or http://www.sony.com/

Declaration of Conformity

Trade Name: 

SONY

Model No.: 

MDR-RF912R

 

(Headphones Unit)

Responsible Party:  Sony Electronics Inc.
Address: 

16535 Via Esprillo, San Diego, CA 
92127 USA

Telephone No.: 

858-942-2230

This device complies with Part 15 of the FCC Rules. 
Operation is subject to the following two conditions: (1) 
this device may not cause harmful interference, and (2) 
this device must accept any interference received, 
including interference that may cause undesired 
operation.

Note

This equipment has been tested and found to comply with 
the limits for a Class B digital device, pursuant to Part 15 of 
the FCC Rules. These limits are designed to provide 
reasonable protection against harmful interference in a 
residential installation. This equipment generates, uses 
and can radiate radio frequency energy and, if not 
installed and used in accordance with the instructions, 
may cause harmful interference to radio communications.
However, there is no guarantee that interference will not 
occur in a particular installation. If this equipment does 
cause harmful interference to radio or television reception, 
which can be determined by turning the equipment off 
and on, the user is encouraged to try to correct the 
interference by one or more of the following measures:

 

– Reorient or relocate the receiving antenna.

 

– Increase the separation between the equipment and 

receiver.

 

– Connect the equipment into an outlet on a circuit 

different from that to which the receiver is connected.

 

– Consult the dealer or an experienced radio/ TV 

technician for help.

For the customers in Canada

This device complies with Industry Canada’s licence-
exempt RSSs. Operation is subject to the following two 
conditions:
(1)This device may not cause interference; and
(2)This device must accept any interference, including 
interference that may cause undesired operation of the 
device.

For the customers in the USA and 

Canada

RECYCLING NICKEL METAL 
HYDRIDE BATTERIES

Nickel Metal Hydride batteries are 
recyclable. You can help preserve our 
environment by returning your used 
rechargeable batteries to the collection 
and recycling location nearest you.

For more information regarding recycling of 
rechargeable batteries, call toll free 1-800-822-8837, or 
visit http://www.call2recycle.org

Caution:
Do not handle damaged or leaking Nickel Metal 
Hydride batteries.

(Red)

(Off)

Complete when indicator 
turns off.

After use

Take off the headphones, then turn off the power.

About sending RF signals

The transmitter starts sending RF signals automatically 
when it detects an audio signal from the connected 
component.

Notes

ˋ

ˋ

If hiss is heard, move closer to the transmitter.

ˋ

ˋ

You may hear some noise when you disconnect the 
AC adaptor from the transmitter before turn off the 
headphones.

If no signal or low signal is input 
for about 4 minutes

If the transmitter does not detect an audio signal for 
about 4 minutes, it will stop sending RF signals 
automatically*, and the POWER indicator will blink for  
1 minute, then turn off. The transmitter restarts after 
receiving an audio signal again.
The transmitter may also turn off if low signal is input 
for about 4 minutes. In this case, raise the volume of 
the connected A/V component within the range where 
the sound is not distorted, then lower the volume of 
the headphones.
*  If signal noise is output from the connected A/V 

component, the transmitter may not turn off, even 
when no audio signal is input.

Set the ATT (attenuator) switch to 0dB. Then, raise the 
volume of the connected A/V component within the 
range where the sound is not distorted, and lower the 
volume of the headphones.

Tips for charging

Charge the headphones first

The supplied rechargeable nickel-metal hydride battery is 
not charged from the first time you use them. Charge 
them before use.

If the transmitter’s POWER indicator 
does not light up red

Check if the switch on the left housing of the headphones 
is set to OFF. If the switch is set to ON, the POWER 
indicator does not light up.
You cannot charge any rechargeable battery or dry battery 
other than the supplied battery.

Charging and usage time

Approx. charging time

Approx. usage time

1)

1 hour
7 hours

2)

90 minutes

3)

13 hours

3)

1) at 1 kHz, 1 mW + 1 mW output
2) hours required to fully charge an empty battery
3) Time may vary, depending on the temperature or 

conditions of use.

To recharge supplied battery after 
use

Connect the headphones to the CHARGE plug of the 
transmitter after use. The POWER indicator lights up red, 
then charging starts.
When charging is complete, there is no need to remove 
the headphones from the transmitter.

Remaining battery

To check the remaining battery charge of the headphones, 
turn on the switch located on the left housing of the 
headphone, and check the POWER indicator located on 
the left housing. The battery is still serviceable when the 
indicator lights up red.
Charge the headphones if the POWER indicator light dims, 
flashes, or the sound becomes distorted or noisy.

Notes

ˋ

ˋ

Do not connect the CHARGE plug to anything other 
than these headphones.

ˋ

ˋ

The transmitter automatically stops sending RF signals 
while charging the battery.

ˋ

ˋ

This system is designed to charge only the supplied 
rechargeable battery type BP-HP550-11 for safety. Note 
that other types of rechargeable battery cannot be 
charged with this system.

ˋ

ˋ

If dry batteries are installed, they cannot be charged.

ˋ

ˋ

Do not attempt to use the supplied BP-HP550-11 
rechargeable battery for other components. They are 
for use with this system only.

ˋ

ˋ

Charge in an environmental temperature of between 
0 °C and 40 °C (between 32 °F and 104 °F).

Tips for volume setting

When watching videos, be careful not to raise the volume 
too high in quiet scenes. You may hurt your ears when a 
loud scene is played.

To set the input level

If the volume is high using the analogue input, set the ATT 
(attenuator) switch to “–6 dB.”

Setting

Connected components

0 dB

TV, portable components and other 
components with a low output level (initial 
settings)

-6 dB

Other components

Notes

ˋ

ˋ

Be sure to lower the volume before setting the ATT 
switch.

ˋ

ˋ

If audio input is distorted (sometimes, noise can be 
heard at the same time), set the ATT switch to “–6 dB.”

Using the headphones 
with separately-sold dry 
batteries

Commercially available (LR03 (size AAA)) dry batteries can 
also be used to power the headphones. Install two 
batteries in the same manner as described in step 1 of 
“How to use.”
When dry batteries are installed, the battery charge 
function is not activated.

Battery life

Battery

Approx. usage time

1)

Sony alkaline battery LR03 
(size AAA)

28 hours

2)

1) at 1 kHz, 1 mW + 1 mW output
2) Time may vary, depending on the temperature or 

conditions of use.

Tips for better reception

Receiving performance

This system utilizes very high frequency signals in the 900 
MHz band so the receiving performance may deteriorate 
due to the surroundings. The following examples illustrate 
conditions that may reduce the reception range or cause 
interference.

ˋ

ˋ

Inside a building with walls containing steel beams.

ˋ

ˋ

An area with many steel file cabinets, etc.

ˋ

ˋ

An area with many electrical appliances capable of 
generating electromagnetic fields.

ˋ

ˋ

The transmitter is placed on a metal instrument.

ˋ

ˋ

An area facing a roadway.

ˋ

ˋ

Noise or interfering signals exist in the surroundings 
due to radio transceivers in trucks, etc.

ˋ

ˋ

Noise or interfering signals exist in the surroundings 
owing to wireless communication systems installed 
along roadways.

Effective area of the transmitter

The optimum distance is up to approximately 45 m (150 ft) 
without the system picking up some interference. 
However, the distance may vary depending on the 
surroundings and environment.

ˋ

ˋ

If the system picks up some noise within the above 
mentioned distance, reduce the distance between the 
transmitter and the headphones, or select another 
channel.

ˋ

ˋ

When you use the headphones inside the effective area 
of the transmitter, the transmitter can be placed in any 
direction from the listener.

ˋ

ˋ

Even within the signal reception area, there are some 
spots (dead spots) where the RF signal cannot be 
received. This characteristic is inherent to RF signals, 
and does not indicate malfunction. By slightly moving 
the transmitter, location of the dead spot can be 
changed.

Replacing the earpads

The earpads are replaceable. If the earpads become dirty 
or worn out, replace them as illustrated below. The 
earpads are not commercially available. You can order 
replacements from the store where you purchased this 
system, or at your nearest Sony dealer.

Remove the old earpad by pulling it out of the groove 
on the housing.

Place the new earpad on the driver unit.
Hang the edge of the earpad on one side of the driver 
unit’s groove edge, then turn the edge of earpad 
around the driver unit as illustrated below.
When the earpad is securely inserted into the groove, 
adjust the earpad to the vertical position.

Troubleshooting

If you run into any problems using this system, use the 
following checklist. Should any problem persist, consult 
your nearest Sony dealer.

No sound/Low sound

ˋ

ˋ

Turn on the headphones.

ˋ

ˋ

Check the connection of the transmitter and A/V 
component, AC adaptor, and AC outlet.

ˋ

ˋ

Check that the A/V component is turned on.

ˋ

ˋ

If you connect the transmitter to the headphone jack of 
an A/V component, raise the volume level on the 
connected A/V component within the range where the 
sound is not distorted.

ˋ

ˋ

Change the radio frequency with the CHANNEL selector 
on the transmitter, then change the radio frequency to 
that of the transmitter with the channel switch on the 
headphones.

ˋ

ˋ

Charge the supplied rechargeable battery, or replace 
dry batteries with new ones. If the POWER indicator is 
still off after charging, take the headphones to a Sony 
dealer.

The sound cuts off

ˋ

ˋ

The transmitter turns off if no signal or low signal is 
input for 4 minutes. If you connect the transmitter to an 
A/V component using the headphone jack, raise the 
volume level on the connected A/V component within 
the range where the sound is not distorted.

Distorted or intermittent sound  
(sometimes with noise)

ˋ

ˋ

Use the headphones near the transmitter, or change 
the position of the transmitter.

ˋ

ˋ

If you connect the transmitter to an A/V component 
using the headphone jack, lower the volume level on 
the connected A/V component within the range where 
the sound is not distorted.

ˋ

ˋ

Change the radio frequency with the CHANNEL selector 
on the transmitter, then change the radio frequency to 
that of the transmitter with the channel switch on the 
headphones.

ˋ

ˋ

Charge the supplied rechargeable battery, or replace 
dry batteries with new ones. If the POWER indicator is 
still off after charging, take the headphones to a Sony 
dealer.

Loud background noise

ˋ

ˋ

If you connect the transmitter to the headphone jack of 
an A/V component, raise the volume level on the 
connected A/V component within the range where the 
sound is not distorted.

ˋ

ˋ

Charge the supplied rechargeable battery, or replace 
dry batteries with new ones. If the POWER indicator is 
still off after charging, take the headphones to a Sony 
dealer.

ˋ

ˋ

Use the headphones near the transmitter.

Battery cannot be charged/ 
POWER indicator does not light up 
red

ˋ

ˋ

Install the supplied rechargeable nickel-metal hydride 
battery. Dry batteries and rechargeable batteries other 
than the supplied cannot be charged.

ˋ

ˋ

Check if the switch on the left housing of the 
headphones is set to OFF. If the switch is set to ON, the 
POWER indicator does not light up.

Short usage time (the supplied 
rechargeable battery)

ˋ

ˋ

Clean the + and - terminal of the supplied rechargeable 
battery and the charging terminal of transmitter/
headphone with a dry cloth.

ˋ

ˋ

Recharge the supplied rechargeable battery after the 
fully discharged.

ˋ

ˋ

If the usage time is still short, consult your nearest Sony 
dealer.

Precautions

Notes on the AC adaptor

ˋ

ˋ

Insert the AC adaptor plug firmly.

ˋ

ˋ

Be sure to use the supplied AC adaptor. Using AC 
adaptors with different plug polarity or other 
characteristics can cause product failure.

Unified 
polarity plug

ˋ

ˋ

Be sure to always use the supplied AC adaptor. Even AC 
adaptors having the same voltage and plug polarity can 
damage this product due to the current capacity or 
other factors.

On power sources and placement

ˋ

ˋ

When this system is not to be used for a long period of 
time, disconnect the AC adaptor from the AC outlet 
holding the plug, and remove the battery from the 
headphones to avoid damage caused by battery 
leakage and subsequent corrosion.

ˋ

ˋ

Do not leave this system in a location subject to direct 
sunlight, heat or moisture.

ˋ

ˋ

Avoid exposure to temperature extremes, direct 
sunlight, moisture, sand, dust or mechanical shock.

ˋ

ˋ

Please note that water does not splash, this product is 
not waterproof specification.

Specifications

General

Carrier frequency 

915.5 MHz, 916.5 MHz

Channel  

Ch1, Ch2

Modulation 

FM stereo

Transmission distance  

Approx. 45m (150 ft) of longest.

Operating temperature 

 

0°C to 40°C (32 °F to 104 °F)

Frequency response 

20 Hz – 20,000 Hz

RF stereo transmitter (TMR-RF912R)

Power source 

DC 12 V: supplied AC adaptor

Audio input 

Stereo mini plug

Dimensions 

Approx. 108 mm × 128 mm × 108 mm 
(4 3/8 × 5 1/8 × 4 3/8 in) (w/h/d)

Mass 

Approx. 137 g (4.83 oz)

Rated power consumption 

3 W

Wireless stereo headphones  
(MDR-RF912R)

Power source 

Supplied rechargeable nickel-metal 
hydride battery BP-HP550-11 or 
commercially available (size AAA) 
dry-cell batteries

Mass 

Approx. 270 g (9.52 oz) (including the 
supplied rechargeable nickel-metal 
hydride battery)

Rated power consumption 

2 W

Included items

RF stereo transmitter TMR-RF912R
Wireless stereo headphones MDR-RF912R
AC adaptor (12 V) (1)
Rechargeable nickel-metal hydride battery BP-HP550-11 (1)
Card warranty (1)
Operating Instructions (this manual) (1)

Design and specifications are subject to change without 
notice.

To AC outlet

Connect the AC 
adaptor.

Insert the plug firmly.

Press and turn the lid counterclockwise.

Match the 

 terminals on 

the battery to the 

 marks 

in the comportment.

Press and turn the lid clockwise.

L (white)

R (red)

Plug adaptor (Stereo mini jack ×1 

 Pin plug ×2, not supplied)

Audio out  
(L/R) jacks

Stereo system, Blu-ray Disc 
player, DVD player, TV*, etc.

*  In case of no headphone 

jack.

If the sound is distorted by connecting the transmitter 
to the A/V component’s audio out (L/R) jacks, 
reconnect the transmitter to the headphone jack.

 Using the audio out (L/R) jacks of the A/V component

Use a plug adaptor (not supplied) between the transmitter and the A/V component.

If you want to receive audio on the headphones while at the same time hearing audio 
from the television speakers: 
connect the transmitter to your Cable Box/Satellite Box rather than your television.

Set the volume of the A/V component as high as possible, but not so high that the 
audio signal becomes distorted.

Wireless Stereo 

Headphone System

Operating Instructions

4-725-918-

11

(1) 

MDR-RF912RK

 

©2017 Sony Corporation  Printed in China

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