HD 450SE
Around-ear headphones
Model: SEBT4
Instruction manual
Use the search function, the navigation (left) or the following links:
Start
“Product overview”
“Getting started”
“Using the headphones”
“FAQ/If a problem occurs ...”
“Specifications”
Sennheiser electronic GmbH & Co. KG
Am Labor 1
30900 Wedemark
Germany
www.sennheiser.com
Version: 05/21 A01
HD 450SE | 1
Important safety instructions
Important safety instructions
▷ Read this instruction manual carefully and completely before
using the product.
▷ Always include this instruction manual when passing the product
on to third parties.
▷ Do not use the product if it is obviously defective or makes loud,
unusual (whistling or beeping) noise.
▷ Only use the product in environments where Bluetooth® wireless
transmission is permitted.
Preventing damage to health and accidents
▷ Protect your hearing from high volume levels. Permanent
hearing damage may occur when headphones are used
at high volume levels for long periods of time. Sennheiser
headphones sound exceptionally good at low and medium volume
levels.
▷ The product generates stronger permanent magnetic
fields that could cause interference with cardiac pacemakers, implanted defibrillators (ICDs) and other
implants. Always maintain a distance of at least 3.94"/10 cm
between the product component containing the magnet and the
cardiac pacemaker, implanted defibrillator, or other implant.
▷ Keep the product, accessories and packaging parts out of reach
of children and pets to prevent accidents. Swallowing and choking hazard.
▷ Do not use the product in an environment that requires your spe-
cial attention (e.g. in traffic or when performing skilled jobs).
Preventing damage to the product and malfunctions
▷ Always keep the product dry and do not expose it to extreme tem-
peratures (hairdryer, heater, extended exposure to sunlight, etc.)
to avoid corrosion or deformation. The normal operating temperature is from 0 to 40 °C/32 to 104 °F.
▷ To avoid loud, unusual (whistling or beeping) noise and to ensure
proper noise cancellation, do not cover the microphone openings
of the active noise cancellation circuitry located on the outside of
the ear cups.
▷ Use only attachments/accessories/spare parts supplied or rec-
ommended by Sennheiser.
▷ Clean the product only with a soft, dry cloth.
▷ Use the product with care and store it in a clean, dust-free envi-
ronment.
Safety instructions for the lithium polymer rechargeable battery
WARNING
If abused or misused, the rechargeable batteries may leak.
In extreme cases, they may even present a risk of:
• heat generation,
• fire development,
•explosion,
•smoke or gas development.
2 | HD 450SE
Important safety instructions
Only use rechargeable batteries and chargers
recommended by Sennheiser.
Only charge the product / rechargeable batteries at
ambient temperatures between +10 °C to +40 °C/50 °F
to 104 °F.
Do not heat the product / rechargeable batteries above
+70 °C/140 °F. Avoid exposure to sunlight and do not
throw the product / rechargeable batteries into fire.
When not using the product / rechargeable batteries for
extended periods of time, charge them regularly (about
every three months).
Switch rechargeable battery-powered products off after
use.
Dispose of defective products with built-in rechargeable
batteries at special collection points or return them to
your specialist dealer.
Notes on data collection and processing and on firmware updates
This product stores individual settings such as the volume and the
Bluetooth addresses of paired devices. This data is required for the
operation of the product and is not transferred to Sennheiser or companies commissioned by Sennheiser and is not processed.
Using the “Sennheiser Smart Control” app, you can update the firmware of the product for free via an Internet connection. If the device
on which the app is installed is connected to the Internet, the following data is automatically transferred to and processed by Sennheiser
servers in order to provide and transfer suitable firmware updates:
hardware identifier, hardware revision number, firmware version of
the product, operating system type (Android, iOS) and version, version of the app. The data will only be used as specified and will not
be stored permanently.
If you do not want this data to be transferred and processed, do not
connect to the Internet.
HD 450SE | 3
Important safety instructions
Intended use/Liability
These headphones have been designed as an accessory for Bluetooth compliant devices. They are intended for wireless audio communication such as music playback and phone calls via Bluetooth
wireless technology.
It is considered improper use when the product is used for any application not named in the corresponding product documentation.
Sennheiser does not accept liability for damage arising from misuse
or improper use of this product and its attachments/accessories.
Sennheiser is not liable for damages to USB devices that are not consistent with the USB specifications.
Sennheiser is not liable for damages resulting from the loss of connection due to flat or overaged rechargeable batteries or exceeding
the Bluetooth transmission range.
Before putting into operation, please observe the respective country-specific regulations.
4 | HD 450SE
Package contents
Package contents
HD 450SE around-ear headphones
Model: SEBT4
USB charging cable with USB-C and USB-A connector
Analog audio cable with 3.5 mm jack plug and 2.5 mm
jack plug, length approx. 1.5 m
Carry case
Quick guide
Safety guide
Online you can find:
• this detailed instruction manual and additional information
www.sennheiser.com/download
• the Sennheiser Smart Control app for configuring the headphones and for additional functions www.sennheiser.com/smartcontrol
A list of accessories can be found on the HD 450SE product
page at www.sennheiser.com. Contact your local Sennheiser
partner: www.sennheiser.com/service-support.
HD 450SE | 5
Product overview
Right R
Left L
4
5
6
2
7
A
C
B
9
1
8
0
Product overview
HD 450SE model: SEBT4
2
3
Headband
Ear cup joints
Ear cups, steplessly adjustable
On/off button for the headphones and the active noise
cancellation ANC
pressing for 4 seconds activates the Bluetooth pairing
mode
pressing 1x activates/deactivates ANC
LED
Input for analog audio cable;
when a cable is connected, flight mode is activated/Bluetooth is deactivated
USB-C socket for charging
6 | HD 450SE
Product overview
3x
3x
3x
3x
Volume – button (volume down)
Volume + button (volume up)
3-way multi-function button for music and call functions
Voice assistant button
Ear pads
Speech microphones (2 pcs.) for phone calls
Overview of the LED display
During operation
LED Meaning; the headphones
flashes blue 3x switch on
flashes blue 3x
flashes red/
blue
are connected to a device via Bluetooth
are in Bluetooth pairing mode
are not connected to a device via
flashes red 3x
Bluetooth or the connection has been
lost
flashes purple
3x
ANC is activated/deactivated
During phone calls
LED Meaning
flashes blue Incoming call
Incoming call and the rechargeable
flashes red
battery of the headphones is almost
empty
If the LED does not light up immediately during charging, clean
the charging socket and charge the headphones until the LED
lights up again (> 11).
HD 450SE | 7
Product overview
Notes on voice prompts
The headphones output voice prompts for various functions (see
examples below).
Voice prompt Meaning/headphones
“Power on” are switched on
“Power off” are switched off
“Connected” are connected via Bluetooth
“Lost connection” are not connected via Bluetooth
“Pairing” are in Bluetooth pairing mode
“Call rejected” Incoming call rejected
“Call ended” Call ended
“More than xx hours
playtime”
Rechargeable battery has the
stated charge level
“Recharge headset” Rechargeable battery is empty.
Recharge the headphones.
Notes on beeps/acoustic signals
The headphones output beeps/acoustic signals for the following
functions.
Acoustic signal Meaning/headphones...
2x low-pitched beep minimum volume is reached
2x high-pitched beep maximum volume is reached
8 | HD 450SE
Getting started
USB-AUSB-C
“Sennheiser Smart Control”
4s
Hold
Getting started
1. Charging the rechargeable battery
The headphones' rechargeable battery is not fully charged upon
delivery. Before using the headphones for the first time, charge the
rechargeable battery for a complete charging cycle without interruption (> 11).
2. Installing the Smart Control app on your
smartphone
The Sennheiser Smart Control app allows you to use all functions
and settings of the headphones and to e.g. adjust the sound to your
liking using the equalizer (> 15).
3. Connecting the headphones to a Bluetooth
device
Connect the headphones to your smartphone via Bluetooth (> 12).
HD 450SE | 9
Getting started
4. Putting the headphones on and adjusting the
headband
For good sound quality and best possible wearing comfort, the headband can be adjusted to properly fit your head (> 17).
10 | HD 450SE
Using the headphones
Right R
2 HRS
USB-A
USB-C
*
LED Off
Using the headphones
Information on the rechargeable battery and the charging process
The headphones have a built-in rechargeable battery. A complete
charging cycle takes approx. 2 hours. Before using the headphones
for the first time, charge the rechargeable battery for a complete
charging cycle without interruption.
When the headphones are being charged, the LED lights up (> 7).
Once the headphones are fully charged, the LED flashes blue for 5
minutes and then goes off. When the battery charge drops to a criti
cal level, a voice prompt asks you to recharge the headphones
(“Recharge headset”).
Sennheiser recommends using the supplied USB cable and a compatible standard USB power supply for charging the headphones.
While the headphones are being charged, you can still listen to
music or make phone calls. In this case, however, the charging time
may be longer.
-
Charging the headphones' rechargeable battery
1. Connect the USB-C connector of the charging cable to the USB
socket of the headphones.
2. Connect the USB-A connector to a corresponding socket of a USB
power source (*to be ordered separately). Make sure that the USB
power source is connected to the power supply system.
The charging process of the headphones begins. The LED displays the charge status:
HD 450SE | 11
Using the headphones
for 5 min
LED Off
LED Meaning
lights up red Rechargeable battery is being charged
flashes blue
for 5 minutes,
the LED then
goes off
If the LED does not light up immediately during charging, clean
the charging socket and charge the headphones until the LED
lights up again (> 11).
You can speed up the charging process by charging the headphones when they are switched off.
Rechargeable battery is fully charged
Connecting the headphones to a Bluetooth device
To be able to use the Bluetooth connection, you must register both
devices (headphones and e.g. smartphone) once. This process is
called pairing.
If operation differs from the steps mentioned, also refer to the
instruction manual of the Bluetooth device you are using.
When you switch on the headphones for the first time, they
automatically switch to pairing mode.
Information on the Bluetooth wireless connection
The headphones are compatible with Bluetooth 5.0.
If your audio source supports one of the following high-resolution
audio encoding methods, music is automatically played in high audio
quality: aptX, aptX LL or AAC. Otherwise the headphones will play
your music in normal audio quality (SBC).
Paired devices establish the Bluetooth wireless connection immediately after switch-on and are ready for use.
On switch-on, the headphones automatically try to connect to the
last two connected Bluetooth devices. The headphones can save the
connection profiles of up to eight Bluetooth devices with which they
have been paired. Audio playback is only possible from one device at
a time.
If you pair the headphones with the ninth Bluetooth device, the saved
connection profile of the least used Bluetooth device will be overwritten. If you want to re-establish a connection with the overwritten
Bluetooth device, you have to pair the headphones again.
12 | HD 450SE
Using the headphones
Paired and connected Bluetooth device
Paired Bluetooth device (currently not connected)
HD 450SE | 13
Using the headphones
1
3
5
4
2
4s
Hold
HD 450SE
Keyword: 0000
“Connected“
Menu
Add Device
20 cm
Right R
Menu
Bluetooth on
Bluetooth off
ON
OFF
OFF
“Pairing“
Pairing the headphones with a Bluetooth device
1. Switch the headphones off and place them close to the Bluetooth
device (max. 20 cm).
2. Press and hold the on/off button for 4 seconds.
The LED flashes red and blue. The headphones are in pairing
mode.
3. Activate Bluetooth on your Bluetooth device.
4. Via the menu of your Bluetooth device, start the search for new
Bluetooth devices.
All active Bluetooth devices in the proximity of your Bluetooth
device are displayed.
5. From the list of found Bluetooth devices, select “HD 450SE”. If
necessary, enter the default pin code “0000”.
6. If pairing was successful, you hear the voice prompt “Connected”.
The LED flashes blue 3x.
14 | HD 450SE
If no connection is established within 5 minutes, pairing mode
is terminated and the headphones switch to standby mode. If
necessary, repeat the steps described above.
If you switch on the headphones for the first time (the pairing
list is empty), they automatically switch to pairing mode.
Using the headphones
“Sennheiser Smart Control”
Disconnecting the headphones from a Bluetooth device
▷ Via the menu of your Bluetooth device, disconnect the connection
to the headphones.
The headphones are disconnected from the Bluetooth device.
You hear the voice prompt “Lost connection”. The headphones
switch to standby mode.
To delete the Bluetooth pairing list of the headphones, > 31.
Installing the Smart Control app
To make full use of all the settings and functions of the headphones,
you need to have the free Sennheiser Smart Control app installed on
your smartphone.
Download the app from the App Store or Google Play and install it on
your smartphone. Alternatively, you can use your smartphone to
scan the following QR code or to call up the following Internet site:
www.sennheiser.com/smartcontrol
▷ Connect your smartphone to the headphones via Bluetooth (> 12).
▷ Start the Smart Control app.
▷ Follow the instructions in the app.
The Smart Control app recognizes the headphones and activates
all available settings and functions.
For further functions of the headphones, you require the apps
of the respective manufacturers:
• Amazon Alexa app (> 25)
HD 450SE | 15
Using the headphones
1 2
2s
Hold
“Power on“
“Connected“
ON
Switching the headphones on
WARNING
Danger of hearing damage due to high volume levels!
Listening at high volume levels can lead to permanent
hearing defects.
▷ Before putting the headphones on, adjust the volume
to a low level (> 19).
▷ Do not continuously expose yourself to high volume
levels.
1. Unfold both ear cups.
The joints click into place.
2. Press and hold the on/off button for 2 seconds.
The LED flashes blue 3x. You hear the voice prompt “Power on”.
If Bluetooth is activated on the headphones and a paired device is
available, the LED flashes blue 3x and you hear the voice prompt
“Connected”.
If Bluetooth is deactivated on the headphones(> 26), you hear the
voice prompt “Power on” and the active noise cancellation ANC
may be activated (> 20).
Make sure that Bluetooth is already activated on your Bluetooth device when switching on the headphones.
If Bluetooth is activated and the headphones cannot find a
paired Bluetooth device within a few minutes, you hear the
voice prompt “Lost connection”. The LED flashes red 3x. The
headphones switch to standby mode.
16 | HD 450SE
Using the headphones
1
2
2s
Hold
“Power off“
Right RLeft L
Switching the headphones off
1. Press and hold the on/off button for 2 seconds.
2. You hear the voice prompt “Power off” and the LED flashes red 3x.
The headphones switch off.
Putting the headphones on and adjusting the headband
For good sound quality and best possible wearing comfort, the headband can be adjusted to properly fit your head.
▷ Wear the headphones so that the headband runs over the top of
your head. The markings
can be found on the inside of the headband.
R for the right side and L for the left side
▷ Move the ear cups up or down the headband slider until:
– your ears are comfortably covered by the ear pads,
– you feel even, gentle pressure around your ears,
– a snug fit of the headband on the head is ensured.
For optimal sound quality, the ear pads must completely surround
your ears.
HD 450SE | 17
Using the headphones
“Recharge
headset“
“More than xx
hours playtime“
ON
1x
Retrieving information on the battery charge status
When the headphones are connected to your Bluetooth device, the
battery charge status can be displayed on the screen of your smartphone (depending on the device and operating system used).
The Smart Control app also displays the battery charge status.
You can retrieve information on the battery charge status on the
headphones by pressing the center of the volume button 1x.
Voice prompt Meaning
“Recharge headset” The rechargeable battery is empty.
Recharge the rechargeable battery (>
11).
“More than xx hours
playtime”
The remaining battery charge is
displayed in hours.
18 | HD 450SE
Using the headphones
Adjusting the volume
WARNING
Danger of hearing damage due to high volume levels!
Listening at high volume levels can lead to permanent
hearing defects. Toggling between the audio sources
may cause enormous volume jumps that can permanently damage your hearing.
▷ Before putting the headphones on and before tog-
gling between audio sources, adjust the volume to a
low level.
▷ Do not continuously expose yourself to high volume
levels.
You can adjust the playback volume for music and for phone calls.
▷ If you are playing music or are on a call: Press the rear part or the
front part of the volume button to increase or reduce the volume
for music and phone calls.
When the maximum or minimum volume is reached, you hear a beep.
You can also adjust the volume using the connected Bluetooth
device.
HD 450SE | 19
Using the headphones
Information on active noise cancellation ANC
Due to its closed design, the headphones offer effective passive isolation from ambient noise.
In addition, the headphones have an active noise cancellation (ANC)
function, which allows you to reduce ambient noise to a minimum.
Even when ANC is activated, your headphones' sound quality is
always at its best.
You can activate or deactivate ANC when the headphones and your
audio source are connected via Bluetooth or the audio cable (provided that the battery is sufficiently charged).
If you want to create a quiet space in a noisy environment, you can
simply use the headphones – without cable and disconnected from
any Bluetooth device – as noise protection by using ANC (> 20).
Notes on active noise cancellation
• Continuous and uniform noise, such as motor or fan noise, is particularly well suppressed.
• Speech or high-frequency noise is significantly reduced, but can
remain perceptible.
• In very quiet environments, slight noise may occur. In this case,
deactivate ANC.
• If unusual (whistling or beeping) noise occurs, take the headphones off and put them on again. Make sure that the ear cups
properly fit around your ears.
• To avoid loud, unusual (whistling or beeping) noise and to ensure
proper noise cancellation, do not cover the microphone openings
of the active noise cancellation circuitry located on the outside of
the ear cups.
Activating/deactivating the active noise cancellation ANC
▷ Make sure that the headphones are switched on (> 16).
To activate the active noise cancellation ANC:
▷ Press the on/off button 1x.
If you are using Bluetooth:
The LED flashes purple 3x.
If Bluetooth is deactivated (analog audio cable is connected, >
26):
The LED lights up blue.
ANC is activated.
To deactivate the active noise cancellation ANC:
▷ Press the on/off button 1x.
If you are using Bluetooth:
The LED flashes purple 3x.
If Bluetooth is deactivated:
The LED goes off.
ANC is deactivated.
20 | HD 450SE
Using the headphones
ON
ON
ON
Active Noise
Cancellation
LED
3x
3x
OFF
ON
Active Noise
Cancellation
ON
OFF
OFF
Active Noise
Cancellation
LED
OFF
OFF
ON
Active Noise
Cancellation
ANC ON
ANC OFF
1x
1x
Right R
Listening to music using the headphones
You can listen to music when the headphones and your audio source
are connected via Bluetooth (> 12) or the audio cable (> 27).
Controlling music playback
The following music playback functions are only available when the
headphones and the device are connected via Bluetooth. Some
smartphones or music players may not support all functions.
Playing/pausing music
▷ Press the center of the 3-way multi-function button 1x.
3-way multi-function
button
Playing the next track
▷ Slide the 3-way multi-function button backwards.
Press 1x Plays or pauses music
Function
HD 450SE | 21
Using the headphones
3-way multi-function
button
Slide
Function
Plays the next track in the playlist
backwards
Playing the previous track
▷ Slide the 3-way multi-function button forwards.
3-way multi-function
button
Slide
Function
Plays the previous track in the playlist
forwards
22 | HD 450SE
Using the headphones
Right R
Making phone calls using the headphones
The following call functions are only available when the headphones
and smartphone are connected via Bluetooth. Some smartphones or
communication apps may not support all functions.
Making a call
▷ Dial the desired number on your smartphone.
If your smartphone does not automatically transfer the call to the
headphones, select “HD 450SE” as the output device on your
smartphone (see the instruction manual of your smartphone if
necessary).
Accepting/rejecting/ending a call
If your headphones are connected to a smartphone and you receive
a call, you hear a ring tone in the headphones.
If you are playing music when you receive a call, the music pauses
until you end the call.
3-way multi-function button Function
Press 1x
Press 1x
Hold for 2
sec
Press 2x
Hold for 2
sec
Press 1x
Accepts a call
Ends a call
Voice prompt “Call ended”
Rejects a call
Voice prompt “Call rejected”
Redialing
Voice prompt “Redial”
(only when music playback is NOT
active)
Continues the active call and rejects
an incoming call
Puts the active call on hold and
accepts an incoming call
HD 450SE | 23
Using the headphones
3-way multi-function button Function
Press 2x
Press 2x
Ends the active call and accepts an
incoming call
Toggles between active call and call
on hold
24 | HD 450SE
Using the headphones
Right R
1x
Using the voice assistant/voice dialing
▷ Press the voice assistant button once.
The available voice assistant of your smartphone is activated
(depending on the system or app on your smartphone: Siri, Google Assistant, or others. If no voice assistant is available, voice
dialing may be activated).
▷ Ask the voice assistant your question or make a request.
To cancel the voice assistant/voice dialing:
▷ Press the voice assistant button 1x.
If you want to use Amazon Alexa as your voice assistant, you
have to configure the headphones once (> 25).
Using Amazon Alexa as voice assistant
To use Amazon Alexa as a voice assistant, you have to add the headphones to the Amazon Alexa app as a device once and then activate
Alexa via the settings of the Sennheiser Smart Control app:
1. Make sure the headphones are connected to your smartphone via
Bluetooth (> 12).
2. Start the
3. In the Smart Control app, open the settings for your headphones
and activate Amazon Alexa for the voice assistant button.
4. Start the Amazon Alexa app and select “Add Device”.
5. From the list of found devices, select “HD 450SE”.
You can now use Amazon Alexa by pressing the voice assistant
button on your headphones.
Sennheiser Smart Control app (> 15).
HD 450SE | 25
Using the headphones
1 2 3
Smart Control
4 5
Headphone
settings
Amazon Alexa
Add Device
HD 450SE
Adjusting sound effects/the equalizer
To be able to use the sound effects/equalizer, you require the Smart
Control app (> 15).
▷ In the Smart Control app, select the desired sound effects.
The sound effects are stored in the headphones. These sound
settings are active even without using the Smart Control app, i.e.
when you are using another Bluetooth device.
Using the audio cable/activating flight mode
If you connect the audio cable, flight mode is activated and the Bluetooth wireless connection is deactivated.
Use the audio cable when:
• wireless transmission is not allowed, e.g. during aircraft take-off
and landing,
• the headphone's rechargeable battery is empty,
• your audio source doesn't offer a Bluetooth connection.
The functions for controlling music and/or calls or voice assistance
are not possible. The active noise cancellation ANC can be fully used
provided that the rechargeable battery is charged (> 20).
26 | HD 450SE
Using the headphones
Right R
Audio cable
2.5 mm
3.5 mm
OFF
ON
Connecting the headphones using the audio cable
1. Insert the 2.5 mm jack plug of the audio cable straight into the
headphones' audio socket until you feel a resistance.
2. Turn the 2.5 mm jack plug to the right until you feel a resistance.
The jack plug is now locked in place and the audio cable is correctly connected to the headphones.
3. Insert the 3.5 mm jack plug of the audio cable into the audio
output of your smartphone.
The Bluetooth connection is deactivated.
Disconnecting the audio cable from headphones
1. Turn the 2.5 mm jack plug of the audio cable to the left until you
feel a resistance.
2. Pull the 2.5 mm jack plug straight out of the headphones' audio
socket.
3. Pull the 3.5 mm jack plug of the audio cable straight out of the
audio output of your smartphone.
HD 450SE | 27
Using the headphones
1 2
3
Storing and transporting the headphones
Store the headphones in the carry case to prevent damage to the
headphones when you are not using or transporting them.
▷ Fold up the headphones and place them in the carry case as
shown in the illustration.
28 | HD 450SE
Care and maintenance
Right R
Care and maintenance
CAUTION
Liquids can damage the electronics of the product!
Liquids entering the housing of the product can cause a short-circuit
and damage the electronics.
▷ Keep all liquids far away from the product.
▷ Do not use any solvents or cleansing agents.
▷ Clean the parts of the product only with a soft, dry cloth.
Replacing the ear pads
For reasons of hygiene, you should replace the ear pads from time to
time. Spare ear pads are available from your Sennheiser partner.
1. Peel the ear pad up and away from the ear cup.
2. Assign the right ear pad to the right ear cup and the left ear pad
to the left ear cup.
3. Place the new ear pad onto the ear cup. Make sure that the seam
of the ear pad points downwards.
4. Place the ear pad around the ear cup so that the ear pad is fixed
in the notch of the ear cup.
Information on the built-in rechargeable battery
Sennheiser ensures and guarantees that the rechargeable batteries
perform at their optimum upon purchase of the product. If, upon purchase or within the warranty period, you suspect that a rechargeable
battery is obviously defective or if a charging error/battery error is
displayed (> 7), stop using the product, disconnect it from the power
supply system and contact your Sennheiser partner. Your Sennheiser partner will coordinate the repair/replacement with you.
Do not return a product with a defective battery to your dealer or
Sennheiser partner unless requested to do so. To find a Sennheiser
partner in your country, search at www.sennheiser.com/servicesupport.
Outside the warranty period, you can have the rechargeable battery
replaced for a fee by your Sennheiser service partner. Contact your
local Sennheiser partner: www.sennheiser.com/service-support
HD 450SE | 29
.
Care and maintenance
Installing firmware updates
Firmware updates can be downloaded free of charge from the Internet using the Sennheiser Smart Control app. Sennheiser recommends to always install the latest firmware version to ensure the
best performance of your product.
▷ Connect the headphones to your smartphone and start the Smart
Control app (>
▷ The app provides information on available firmware updates and
guides you through the installation process.
15).
30 | HD 450SE
FAQ/If a problem occurs ...
1 2
5s
Hold
USB-A
USB-C
FAQ/If a problem occurs ...
Current list of frequently asked questions (FAQ)
Visit the HD 450SE product page at
www.sennheiser.com/download
There you will find a current list of frequently asked questions (FAQ)
and suggested solutions.
Your question has not been answered or the problem persists?
If a problem occurs that is not listed in the FAQ section or if the problem cannot be solved with the proposed solutions, please contact
your Sennheiser partner for assistance.
To find a Sennheiser partner in your country, search at
www.sennheiser.com/service-support.
Leaving the Bluetooth transmission range
Wireless calling and streaming are only possible in the Bluetooth
transmission range of your smartphone. The transmission range
largely depends on environmental conditions such as wall thickness,
wall composition etc. With a free line of sight, the transmission
range of most smartphones and Bluetooth devices is up to 10 meters.
If you, and therefore the headphones, leave the Bluetooth transmission range of the smartphone, the sound quality deteriorates
increasingly until you hear the voice prompt “Lost connection” and
the connection breaks down completely. If you immediately re-enter
the Bluetooth transmission range, the connection is automatically
re-established.
Resetting the headphones
If the function of the headphones is disturbed, perform a reset. Individual settings such as the pairing settings are not deleted.
1. Connect the USB-C cable to the headphones and make sure that
the headphones are being charged (>
11).
2. Simultaneously press and hold the one/off button and the rear
part of the volume button (Volume +) for at least 5 seconds.
The reset is completed. Continue to use the headphones as normal.
Deleting the Bluetooth pairing list of the headphones
Make sure that no audio cable is connected to the headphones and
that Bluetooth is activated (> 27).
HD 450SE | 31
FAQ/If a problem occurs ...
1 2
OFF
2s
Hold
4s
Hold
ON
3s
Hold
ON
“Pairing“
1. Switch off the headphones (press and hold the on/off button for
2 seconds) and then start pairing mode (press and hold the on/off
button for 4 seconds) (> 17 and 14).
2. Simultaneously press and hold the on/off button and the 3-way
multi-function button for 3 seconds.
The LED flashes purple 3x. The Bluetooth pairing list is deleted.
The headphones then stay in Bluetooth pairing mode.
32 | HD 450SE
FAQ/If a problem occurs ...
Right R
Audio cable
2.5 mm
3.5 mm
OFF
ON
When using the analog audio cable, the music only plays on one side of the headphones
The jack plug of the audio cable is not properly locked in place in the
headphones' audio socket:
1. Insert the 2.5 mm jack plug of the audio cable straight into the
headphones' audio socket until you feel a resistance.
2. Turn the 2.5 mm jack plug to the right until you feel a resistance.
The jack plug is now locked in place and the audio cable is correctly connected to the headphones.
3. Insert the 3.5 mm jack plug of the audio cable into the audio
output of your smartphone.
The Bluetooth connection is deactivated.
HD 450SE | 33
Specifications
Specifications
Model: SEBT4
Wearing style Bluetooth® around-ear, closed-back
Ear coupling circum-aural
Transducer principle dynamic
Transducer 32 mm
Frequency response 18 Hz to 22,000 Hz (-10 dB)
Sound pressure level (SPL) 108 dB (1 kHz/0 dBFS)
THD (1 kHz, 100 dB SPL) < 0.3 % (1 kHz, 100 dB SPL)
Microphone principle MEMS
Microphone frequency
response
Microphone pick-up pattern
(speech audio)
Power supply built-in rechargeable lithium-polymer
Charging time of
rechargeable battery
Operating time 30 hrs (music playback via Bluetooth
Temperature range operation: 0°C to +40°C
Relative humidity operation: 10 to 80 %, non condensing
Weight (headphones) approx. 238 g
Magnetic field strength 1.9 mT
80 Hz to 6,000 Hz (-3 dB)
dual omni-directional microphones
2-mic beamforming array
battery:
USB charging: 5 V ⎓, 500 mA max.
approx. 2 hours
with ANC activated)
charging: +10°C to +40°C
storage: –20°C to +60 °C
storage: 10 to 90 %
3,7 V ⎓, 600 mAh
34 | HD 450SE
Bluetooth
Version Bluetooth 5.0 compatible, class 1, BLE
Transmission frequency 2,402 MHz to 2,480 MHz
Modulation GFSK, π/4 DQPSK, 8DPSK
Output power 12.6 mW (max)
Profiles HSP, HFP, AVRCP, A2DP
Codec aptX, aptX LL, AAC, SBC
Device name HD 450SE
LE-HD 450SE (Bluetooth Low Energy
only)
Number of active
connections
2
Manufacturer Declarations
Manufacturer Declarations
Warranty
Sennheiser electronic GmbH & Co. KG gives a warranty of 24 months
on this product.
For the current warranty conditions, please visit our website at
www.sennheiser.com or contact your Sennheiser partner.
In compliance with the following requirements
• General Product Safety Directive (2001/95/EC)
•Compliant to Sound Pressure Limits according to country specific requirements
EU declaration of conformity
• RoHS Directive (2011/65/EU)
Hereby, Sennheiser electronic GmbH & Co. KG declares that the
radio equipment type SEBT4 is in compliance with the Radio Equipment Directive (2014/53/EU).
The full text of the EU declaration of conformity is available at the following Internet address: www.sennheiser.com/download.
Notes on disposal
• WEEE Directive (2012/19/EU)
• Battery Directive (2006/66/EC & 2013/56/EU)
The symbol of the crossed-out wheeled bin on the product, the battery/rechargeable battery (if applicable) and/or the packaging indicates that these products must not be disposed of with normal
household waste, but must be disposed of separately at the end of
their operational lifetime. For packaging disposal, please observe the
legal regulations on waste segregation applicable in your country.
Further information on the recycling of theses products can be
obtained from your municipal administration, from the municipal collection points, or from your Sennheiser partner.
The separate collection of waste electrical and electronic equipment, batteries/rechargeable batteries (if applicable) and packagings is used to promote the reuse and recycling and to prevent negative effects caused by e.g. potentially hazardous substances
contained in these products. Herewith you make an important contribution to the protection of the environment and public health.
Trademarks
Sennheiser is a trademark of Sennheiser electronic GmbH & Co. KG,
registered in the U.S. and other countries.
Apple, the Apple logo and Siri are trademarks of Apple Inc., registered in the U.S. and other countries. App Store is a service mark of
Apple Inc.
Android and Google Play are registered trademarks of Google Inc.
The Bluetooth® word mark and logos are registered trademarks
owned by Bluetooth SIG, Inc. and any use of such marks by Sennhe
iser electronic GmbH & Co. KG is under license.
Qualcomm aptX is a product of Qualcomm Technologies International, Ltd. Qualcomm is a trademark of Qualcomm Incorporated,
registered in the United States and other countries, used with permission.
-
HD 450SE | 35
Manufacturer Declarations
aptX is a trademark of Qualcomm Technologies International, Ltd.,
registered in the United States and other countries, used with permission.
Amazon, Alexa and all related logos are trademarks of Amazon.com,
Inc. or its affiliates.
Other product and company names mentioned in the user documentation may be the trademarks or registered trademarks of their
respective holders.
36 | HD 450SE
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