Sennheiser HD 450BT, SEBT4 - Around-Ear Headphones Manual

Contents

1 Important safety instructions
- 1.1 Notes on data collection and processing and on firmware updates
- 1.2 Intended use/Liability
2 Package contents
3 Product overview
4 Getting started
5 Using the device
6 Care and maintenance
7 FAQ/If a problem occurs
8 Specifications
9 References
10 Download manual
11 In Other Languages

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 special 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 temperatures (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 recommended by Sennheiser.
Clean the product only with a soft, dry cloth.
Use the product with care and store it in a clean, dust-free environment.

Safety instructions for the lithium polymer rechargeable battery

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.

	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.

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.

Package contents

Online you can find:

the Sennheiser Smart Control app for configuring the headphones and for additional functions www.sennheiser.com/smart control

A list of accessories can be found on the HD 450BT product page at www.sennheiser.com. Contact your local Sennheiser partner: www.sennheiser.com/service-support.

Product overview

HD 450BT model: SEBT4

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
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
3x	flashes blue 3x	switch on
3x	flashes blue 3x	are connected to a device via Bluetooth
	flashes red/ blue	are in Bluetooth pairing mode
3x	flashes red 3x	are not connected to a device via Bluetooth or the connection has been lost
3x	flashes purple 3x	ANC is activated/deactivated
During phone calls
LED		Meaning
	flashes blue	Incoming call
	flashes red	Incoming call and the rechargeable 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.

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

Getting started

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.

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.

Connecting the unit to a Bluetooth device

Connect the headphones to your smartphone via Bluetooth.

Putting the unit on and adjusting the headband

For good sound quality and best possible wearing comfort, the headband can be adjusted to properly fit your head.

Using the device

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. Once the headphones are fully charged, the LED flashes blue for 5 minutes and then goes off. When the battery charge drops to a critical 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 unit's rechargeable battery

Connect the USB-C connector of the charging cable to the USB socket of the headphones.
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:

LED		Meaning
	lights up red	Rechargeable battery is being charged
	flashes blue for 5 minutes, the LED then goes off	Rechargeable battery is fully charged

If the LED does not light up immediately during charging, clean the charging socket and charge the headphones until the LED lights up again.

You can speed up the charging process by charging the headphones when they are switched off.

Connecting the device 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.

	Paired and connected Bluetooth device
	Paired Bluetooth device (currently not connected)

Pairing the unit with a Bluetooth device

Switch the headphones off and place them close to the Bluetooth device (max. 20 cm).
Press and hold the on/off button for 4 seconds.
The LED flashes red and blue. The headphones are in pairin g mode.
Activate Bluetooth on your Bluetooth device.
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.
From the list of found Bluetooth devices, select "HD 450BT". If necessary, enter the default pin code "0000".
If pairing was successful, you hear the voice prompt "Connected".The LED flashes blue 3x.

If no connection is established within 5 minutes, paired 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.

Disconnecting the device 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 headphone s switch to standby mode.

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.
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.

Switching the unit on

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.
Do not continuously expose yourself to high volume levels.

Unfold both ear cups.
The joints click into place.
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, you hear the voice prompt "Power on" and the active noise cancellation AN C may be activated.

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.

Switching the unit off

Press and hold the on/off button for 2 seconds.
You hear the voice prompt "Power off" and the LED flashes red 3x. The headphones switch off.

Putting the unit 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 R for the right side and L for the left side can be found on the inside of the headband.
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 surroun d your ears.

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.
"More than xx hours playtime"	The remaining battery charge is displayed in hours.

Adjusting the volume

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 toggling 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 adjust the volume using the connected Bluetooth device

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.

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 cup s properly fit around your ears.
To avoid loud, unusual (whistling or beeping) noise and to ensure proper noise cancellation, do not cover the microphone opening s 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.

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,):
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.

Listening to music using the headphones

You can listen to music when the headphones and your audio source are connected via Bluetooth or the audio cable.

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		Function
	Press 1x	Plays or pauses music
Playing the next track Slide the 3-way multi-function button backwards.
3-way multi-function button		Function
	Slide backwards	Plays the next track in the playlist
Playing the previous track Slide the 3-way multi-function button forwards.
3-way multi-function button		Function
	Slide forwards	Plays the previous track in the playlist

Making phone calls using the device

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 450BT" 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	Accepts a call
	Press 1x	Ends a call Voice prompt "Call ended"
	Hold for 2 sec	Rejects a call Voice prompt "Call rejected"
	Press 2x	Redialing Voice prompt "Redial" (only when music playback is NOT active)
	Hold for 2 sec	Continues the active call and rejects an incoming call
	Press 1x	Puts the active call on hold and accepts an incoming call
	Press 2x	Ends the active call and accepts an incoming call
	Press 2x	Toggles between active call and call on hold

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.

Adjusting sound effects/the equalizer

To be able to use the sound effects/equalizer, you require the Smart Control app.

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.

Connecting the unit using the audio cable

Insert the 2.5 mm jack plug of the audio cable straight into the headphones' audio socket until you feel a resistance.
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.
Insert the 3.5 mm jack plug of the audio cable into the audiooutput of your smartphone. The Bluetooth connection is deactivated.

Disconnecting the audio cable from headphones

Turn the 2.5 mm jack plug of the audio cable to the left until you feel a resistance.
Pull the 2.5 mm jack plug straight out of the headphones' audio socket.
Pull the 3.5 mm jack plug of the audio cable straight out of th eaudio output of your smartphone.

Storing and transporting the device

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.

Care and maintenance

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.

Peel the ear pad up and away from the ear cup.
Assign the right ear pad to the right ear cup and the left ear pa dto the left ear cup
.
Place the new ear pad onto the ear cup. Make sure that the sea mof the ear pad points downwards.
Place the ear pad around the ear cup so that the ear pad is fixe din 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, 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.

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.

FAQ/If a problem occurs

Current list of frequently asked questions (FAQ)
Visit the HD 450BT 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 device

If the function of the headphones is disturbed, perform a reset. Individual settings such as the pairing settings are not deleted.

Connect the USB-C cable to the headphones and make sure tha tthe headphones are being charged.
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 unit

Make sure that no audio cable is connected to the headphones and that Bluetooth is activated.

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).
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.

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:

Insert the 2.5 mm jack plug of the audio cable straight into the headphones' audio socket until you feel a resistance.
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.
Insert the 3.5 mm jack plug of the audio cable into the audiooutput of your smartphone.
The Bluetooth connection is deactivated.

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	80 Hz to 6,000 Hz (-3 dB)
Microphone pick-up pattern (speech audio)	dual omni-directional microphones 2-mic beamforming array
Power supply	built-in rechargeable lithium-polymer battery: 3,7 V ⎓, 600 mAh USB charging: 5 V ⎓, 500 mA max.
Charging time of rechargeable battery	approx. 2 hrs
Operating time	30 hrs (music playback via Bluetooth with ANC activated)
Temperature range	operation: 0°C to +40°C charging: +10°C to +40°C storage: –20°C to +60°C
Relative humidity	operation: 10 to 80%, non condensing storage: 10 to 90%
Weight (headphones)	approx. 238 g
Magnetic field strength	1.9 mT
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 450BT LE-HD 450BT (Bluetooth Low Energy only)
Number of active connections	2