Audio T Verdict
The Sennheiser BTA1 TV Transmitter is a clever solution to a problem that becomes increasingly obvious when you try using ordinary Bluetooth headphones with a television: lip-sync delays, awkward pairing and limited support for more than one listener.
Rather than relying on conventional point-to-point Bluetooth audio, the BTA1 uses Auracast and the LC3 codec to broadcast TV sound to compatible headphones with very low latency. One broadcast can serve multiple listeners, each using their own compatible headphones and controlling their own listening level.
The real appeal is how much functionality Sennheiser has packed into such a small box. HDMI ARC, optical and analogue inputs cover a wide range of televisions and other sources, while Speech Clarity, Virtual Surround Sound and Normalize Volume provide useful adjustments specifically designed around watching television.
Important: Auracast Headphones Required
The BTA1 does not transmit to every pair of conventional Bluetooth headphones. Your headphones or earbuds must support Bluetooth Auracast reception. Check compatibility before ordering if you intend to use existing wireless headphones.
Sennheiser BTA1 TV Transmitter
The Sennheiser BTA1 TV Transmitter adds modern Bluetooth Auracast wireless audio to compatible televisions, AV receivers and other audio sources.
Connect the BTA1 to your television using HDMI ARC, optical digital or 3.5mm analogue audio, pair compatible Auracast headphones and the transmitter broadcasts the incoming sound wirelessly using the efficient LC3 Bluetooth codec.
Unlike a conventional Bluetooth connection that is generally centred around one source and one or two listening devices, Auracast is designed for broadcast audio. This allows multiple compatible listeners to tune into the same programme while retaining their own headphone volume and settings.
- Bluetooth Auracast TV audio transmitter
- Designed for compatible Auracast headphones and earbuds
- LC3 Bluetooth audio codec
- Very low-latency audio transmission
- Up to 50m specified transmission range
- Unlimited compatible Auracast listeners
- HDMI ARC audio input
- Optical mini-TOSLINK digital input
- 3.5mm stereo analogue input
- Stereo PCM support
- Dolby Digital AC-3 support
- Speech Clarity mode
- Virtual Surround Sound
- Normalize Volume
- Optional encrypted Auracast broadcast
- Sennheiser Smart Control Plus app support
- USB powered
- USB power output for charging compatible headphones
- Approximately 100g
- Compact 130 x 20 x 56mm design
Turn Your TV Into an Auracast Source
Most televisions do not currently contain an Auracast transmitter.
The BTA1 effectively adds that functionality externally, taking the audio signal from your television and broadcasting it wirelessly to compatible listening devices.
This makes it particularly useful if you want private TV listening without running a headphone cable across the room.
What Is Bluetooth Auracast?
Auracast is a Bluetooth broadcast-audio technology.
Instead of pairing one source exclusively with one listening device, an Auracast transmitter can create a broadcast that multiple compatible receivers can join.
For television listening, that means one BTA1 can provide the same programme audio to several compatible headphones simultaneously.
Multiple Listeners From One Transmitter
Sennheiser specifies that the BTA1 can broadcast to an unlimited number of compatible Auracast headphones within its usable transmission area.
That makes it useful for situations such as:
- Couples watching television together
- Families wanting different listening volumes
- Several people following the same film or sporting event
- Shared viewing where some people use headphones and others use the TV speakers
- Schools and educational spaces
- Residential and care environments
- Other group listening applications
Independent Listening Volume
Each listener can use the controls available on their compatible Auracast headphones rather than everybody being forced to listen at one common volume.
This can be particularly helpful where two people have very different preferred listening levels.
Keep the TV Speakers Running
With a suitable television setup, the BTA1 can broadcast to headphones while the television's own speakers remain available for somebody else in the room.
Whether the television can output to its speakers and an external audio connection simultaneously depends on the TV and the connection being used.
TV Speaker Behaviour Varies
Some televisions automatically mute their speakers when a 3.5mm headphone or analogue output is used. HDMI ARC or optical can often be a better option where you want the television speakers and BTA1 headphones operating together, but check the audio-output options of your particular TV.
Up to 50 Metres Wireless Range
Sennheiser specifies an Auracast transmission range of up to 50 metres.
Actual performance will depend on the building, walls, interference and the receiving device, but the extended range means you are not restricted to sitting immediately beside the television.
This gives listeners freedom to move around a room or nearby area while continuing to hear the programme.
LC3 Bluetooth Audio
The BTA1 uses the LC3 codec for its Auracast audio transmission.
LC3 forms part of the Bluetooth LE Audio platform and has been designed to provide efficient high-quality audio while using comparatively low data rates.
For television use, its low-latency characteristics are particularly valuable because dialogue needs to remain closely synchronised with what is happening on screen.
Better Lip-Sync
Noticeable delay is one of the most distracting problems when using unsuitable Bluetooth equipment for television.
If the audio arrives significantly after the picture, voices appear disconnected from the people speaking and sound effects no longer correspond properly with the action.
The BTA1's Bluetooth LE Audio transmission has been designed specifically to keep wireless audio closely synchronised with television pictures.
Speech Clarity
Speech Clarity is designed to make dialogue easier to understand.
Rather than simply turning the entire soundtrack up, the processing places greater emphasis on voices so they stand more clearly against music and background effects.
This can be especially useful with:
- Drama
- Films with dense soundtracks
- News and documentaries
- Quietly mixed dialogue
- Listening at lower overall volume
Virtual Surround Sound
Virtual Surround Sound provides an alternative presentation for films, television and sport.
The processing is designed to make the sound feel more spacious and immersive through compatible headphones rather than confining everything to a straightforward left/right stereo image.
It can be switched according to the type of programme and personal preference rather than being permanently imposed on everything you watch.
Normalize Volume
Television volume can vary considerably between quiet dialogue, loud action sequences and advertising.
Normalize Volume reduces those sudden changes, helping prevent the need to continually reach for the volume control.
This can also be useful for evening viewing when large jumps in programme level are particularly unwelcome.
Control Through Smart Control Plus
The BTA1 works with the Sennheiser Smart Control Plus app on compatible iOS and Android devices.
The app provides access to additional transmitter settings including adjustment of Normalize Volume and Auracast privacy options.
Private Encrypted Broadcast
A public Auracast broadcast can be convenient when you deliberately want other compatible receivers to join.
At home, however, you may prefer your television audio to remain private.
The BTA1 allows optional password protection to be added to the Auracast broadcast so access can be restricted.
HDMI ARC Connection
HDMI ARC provides one of the most convenient ways of connecting the BTA1 to a modern television.
Connect the transmitter to the television's ARC-capable HDMI connection and compatible TV audio can be returned to the BTA1 for wireless transmission.
The BTA1 supports stereo PCM and Dolby Digital AC-3 through its digital connections.
HDMI ARC, Not an HDMI Video Input
The BTA1 is an audio transmitter rather than an HDMI video switching device. Its HDMI connection is used for ARC audio from a compatible television or source rather than for passing video through the transmitter.
Dolby Digital Support
The digital input stage supports AC-3 Dolby Digital with a maximum stated bit rate of 640kbps.
The BTA1 automatically adapts to supported Dolby Digital or PCM stereo signals, reducing the need to continually change transmitter settings when moving between compatible sources.
Stereo PCM
Stereo PCM is supported at 44.1kHz and 48kHz sampling rates with 16-bit to 24-bit resolution through the compatible digital inputs.
This provides straightforward support for common television and stereo digital audio signals.
Optical Digital Connection
An optical mini-TOSLINK input provides an alternative to HDMI ARC.
This is particularly useful with televisions, stereo systems and other equipment that provide an optical digital audio output but do not offer a suitable HDMI ARC connection.
3.5mm Analogue Input
A conventional 3.5mm stereo analogue input provides compatibility with older or simpler audio equipment.
This means the BTA1 is not limited to televisions. Any suitable source with an analogue audio output can potentially feed the transmitter.
Possible examples include:
- Televisions
- Stereo systems
- Radios
- AV receivers
- Computers with analogue audio outputs
- Other compatible line or headphone-level sources
Automatic Source Handling
The BTA1 has been designed to keep everyday operation straightforward when several connection options are available.
Once the system has been installed and compatible headphones paired, normal television listening does not require a complicated sequence of menus every time you sit down to watch something.
USB Power
The BTA1 does not contain a large rechargeable battery because it is intended to remain installed beside a television or other source.
It requires a 5V DC USB power supply with a maximum input requirement of 1000mA.
Power can be supplied from a suitable USB socket on the television or another compatible USB power source.
USB Charging Output
The transmitter also provides a 5V DC USB power output rated at up to 500mA.
This can be used for charging compatible headphones, providing a convenient charging point close to the television.
USB Is Primarily for Power
The BTA1 specification lists HDMI ARC, optical mini-TOSLINK and 3.5mm analogue as its audio inputs. The USB connections provide power to the transmitter and a charging output for compatible headphones rather than acting as a general USB audio input from a television.
Compact 130mm-Wide Design
The BTA1 measures approximately 130mm wide, 20mm high and 56mm deep.
At around 100g, it can sit discreetly beside a television, AV receiver or other source without becoming another large piece of equipment in the room.
Works With the Sennheiser RS 275 System
The BTA1 is also the transmitter supplied as part of Sennheiser's RS 275 Wireless Headphones system.
If you already have suitable Auracast headphones and only need the transmitter, buying the BTA1 separately avoids paying for another pair of headphones.
If you want a complete Sennheiser television-listening system straight from the box, the RS 275 combines the BTA1 with matching HDR 275 headphones.
BTA1 or a Complete RS 275 System?
BTA1 TV Transmitter
- Transmitter only
- No headphones included
- For existing Auracast headphones
- HDMI ARC input
- Optical digital input
- 3.5mm analogue input
- LC3 Auracast broadcast
- Up to 50m range
- Multiple compatible listeners
- Speech Clarity
- Virtual Surround Sound
- Normalize Volume
RS 275 TV Headphones
- Complete television headphone system
- BTA1 transmitter included
- HDR 275 headphones included
- Designed to work together out of the box
- Up to 50-hour headphone battery life
- Over-ear headphone design
- Full BTA1 TV connection options
- Auracast transmission
- Suitable for private TV listening
- Expandable to additional compatible listeners
Do My Existing Headphones Work?
The important specification to look for is Auracast reception.
A headphone may support ordinary Bluetooth and still be incompatible with an Auracast broadcast.
Do not assume that Bluetooth 5.x, Bluetooth LE or simply being a recent wireless headphone automatically guarantees BTA1 compatibility.
Check Before Ordering
If you already own wireless headphones and are buying the BTA1 specifically for them, check that the exact headphone model supports receiving an Auracast broadcast. If you are unsure, speak to Audio T before ordering.
Why Not Just Use the TV's Bluetooth?
Some modern televisions already include conventional Bluetooth headphone support.
That can work perfectly well for straightforward single-person listening, but functionality varies considerably between televisions.
Depending on the TV, limitations can include:
- Noticeable audio delay
- Limited simultaneous headphone connections
- TV speakers automatically muting
- Limited dialogue enhancement
- No broadcast functionality
- More complicated pairing behaviour
The BTA1 provides a dedicated television-listening system rather than relying on whatever Bluetooth implementation happens to be built into the display.
Useful for Late-Night Viewing
Wireless headphones allow you to listen at a satisfying level without filling the room with television sound.
That makes the BTA1 particularly useful for films, sport or television after other people in the house have gone to bed.
Useful for Different Hearing Preferences
Two people watching the same programme may not necessarily want the same volume.
With compatible Auracast headphones, each listener can control their own listening level rather than continually compromising on one room volume.
Speech Clarity and Normalize Volume provide additional tools where dialogue intelligibility is more important than simply making everything louder.
Useful for Shared Viewing
Auracast broadcast capability means the BTA1 is not restricted to a single listener.
This makes it particularly interesting where several people want private or individual headphone listening from the same source.
Who Is the Sennheiser BTA1 For?
- Owners of compatible Auracast headphones
- Customers wanting wireless TV listening
- People experiencing Bluetooth lip-sync problems with their television
- Couples who prefer different listening volumes
- Households wanting late-night TV listening
- Listeners who benefit from enhanced dialogue clarity
- Users wanting several compatible headphones on one TV
- Customers wanting HDMI ARC connectivity
- Televisions with optical digital outputs
- Older sources requiring 3.5mm analogue input
- Customers who already own Auracast headphones and do not need a complete RS 275 system
Who Is It Not For?
- Owners of Bluetooth headphones without Auracast reception
- Customers expecting headphones to be included
- Anyone wanting a conventional Bluetooth Classic transmitter for legacy headphones
- Systems requiring HDMI video switching or passthrough
- Customers looking for a battery-powered portable Bluetooth transmitter
- Anyone expecting USB audio input from a television or computer
Key Features
- Sennheiser BTA1 TV Transmitter
- Auracast TV audio transmitter
- Bluetooth LE Audio
- LC3 codec
- BAP profile
- PBP profile
- Very low-latency transmission
- Up to 50m specified range
- Unlimited compatible Auracast listeners
- Independent listener volume
- Optional encrypted broadcast
- Optional password protection
- Speech Clarity
- Virtual Surround Sound
- Normalize Volume
- HDMI ARC digital audio input
- Optical mini-TOSLINK input
- 3.5mm stereo analogue input
- Stereo PCM support
- 44.1kHz PCM support
- 48kHz PCM support
- 16-bit to 24-bit PCM support
- Dolby Digital AC-3 support
- Up to 640kbps Dolby Digital
- USB-powered operation
- 5V / 1000mA maximum power input
- USB charging output
- 5V / 500mA maximum charging output
- Sennheiser Smart Control Plus app
- iOS app support
- Android app support
- 130mm width
- 20mm height
- 56mm depth
- Approximately 100g
- Optical cable supplied
- Analogue cable supplied
- USB cable supplied
- Compatible with the Sennheiser RS 275 system
- Headphones not included
- Auracast-compatible headphones required
Frequently Asked Questions
What is the Sennheiser BTA1?
The BTA1 is a television and audio-source transmitter that broadcasts sound wirelessly to compatible Auracast headphones and other suitable Auracast receiving devices.
Are headphones included?
No. This product is the BTA1 transmitter only.
Will the BTA1 work with any Bluetooth headphones?
No. Sennheiser specifies the BTA1 for headphones that support receiving Bluetooth Auracast broadcasts.
What should I look for when checking compatibility?
Confirm that your exact headphone or earbud model supports Auracast reception. Ordinary Bluetooth support alone is not enough.
Does the BTA1 use Bluetooth Classic?
Its audio broadcast system uses Bluetooth Auracast and the LC3 codec rather than acting as a conventional Bluetooth Classic headphone transmitter.
What codec does it use?
LC3.
What Bluetooth profiles are supported?
BAP and PBP.
How far can the BTA1 transmit?
Sennheiser specifies a range of up to 50 metres under suitable conditions.
Can more than one person listen?
Yes. Auracast allows multiple compatible receivers to join the same broadcast.
How many compatible headphones can connect?
Sennheiser describes the BTA1 as supporting an unlimited number of compatible Auracast listeners.
Can everyone use a different volume?
Compatible listeners can control their own headphone volume independently.
Can the television speakers remain on?
Potentially yes, depending on the television and chosen audio output. Some TVs can use their speakers while also feeding an external output, while others mute the speakers with certain connections.
Does it have HDMI?
Yes. It provides an HDMI ARC audio connection.
Does it support HDMI eARC?
Sennheiser specifies HDMI ARC for the BTA1 rather than eARC.
Does HDMI pass video through the BTA1?
No HDMI video passthrough is specified. The HDMI connection is used for television audio through ARC.
Does it have an optical input?
Yes. An optical mini-TOSLINK digital audio input is provided.
Does it have an analogue input?
Yes. A 3.5mm stereo analogue input is provided.
Does it support Dolby Digital?
Yes. Sennheiser specifies AC-3 Dolby Digital at up to 640kbps through the compatible digital inputs.
Does it support stereo PCM?
Yes. Stereo PCM at 44.1kHz or 48kHz and 16-bit to 24-bit resolution is supported.
Does it support Dolby Atmos?
Dolby Atmos is not listed as a supported BTA1 input format. The specified digital formats are stereo PCM and AC-3 Dolby Digital.
What does Speech Clarity do?
Speech Clarity places greater emphasis on dialogue to make voices easier to understand.
What is Virtual Surround Sound?
It is a processing mode designed to create a more spacious and immersive headphone presentation for television, films and sport.
What is Normalize Volume?
Normalize Volume reduces sudden differences between quiet and loud programme material so less manual volume adjustment is required.
Does it work with the Sennheiser Smart Control Plus app?
Yes. Sennheiser specifies Smart Control Plus support for compatible iOS and Android devices.
Can the Auracast broadcast be private?
Yes. Sennheiser provides optional password protection and encryption for the BTA1 broadcast.
Can I use it with an AV receiver?
Yes, provided the receiver has a compatible audio output that can be connected to one of the BTA1 inputs.
Can I use it with a stereo system?
Yes, provided the stereo system provides a suitable optical or analogue audio output.
Does the BTA1 have a battery?
It is designed to be USB powered rather than used as a rechargeable portable transmitter.
Can I power it from my TV?
Yes, if the television provides a suitable USB power output capable of meeting the BTA1's requirements.
What power does it require?
5V DC at up to 1000mA.
Can I charge headphones from the BTA1?
Yes. Sennheiser specifies a USB power output of 5V DC at up to 500mA for headphone charging.
Is USB an audio input?
Sennheiser lists HDMI ARC, optical mini-TOSLINK and 3.5mm analogue as the BTA1 audio inputs. USB is specified for power and headphone charging.
How big is the BTA1?
Approximately 130 x 20 x 56mm.
How much does it weigh?
Approximately 100g.
What cables are supplied?
Sennheiser lists optical, analogue and USB cables with the BTA1 package.
Is the BTA1 included with the RS 275 headphones?
Yes. The complete Sennheiser RS 275 TV Headphones system combines compatible HDR 275 headphones with a BTA1 transmitter.
Should I buy the BTA1 or RS 275?
Choose the BTA1 if you already have compatible Auracast headphones and only need the transmitter. Choose the RS 275 if you want a complete matched TV headphone and transmitter system.
Related Sennheiser Products and Audio T Guides
Why Buy the Sennheiser BTA1 From Audio T?
Auracast is still a relatively new feature, and the biggest thing to establish before buying the BTA1 is whether the headphones you intend to use can actually receive its broadcast. Audio T can help you check compatibility rather than discovering after purchase that ordinary Bluetooth support is not enough.
We can also advise on HDMI ARC, optical and analogue TV connections, compare the standalone BTA1 with the complete Sennheiser RS 275 system and help work out the best way to retain television-speaker sound for other people in the room where your TV allows it.
- Auracast compatibility advice
- Sennheiser TV headphone guidance
- BTA1 and RS 275 comparisons
- HDMI ARC setup advice
- Optical digital connection guidance
- Analogue audio connection advice
- TV audio-format guidance
- Multiple-listener setup advice
- Smart Control Plus guidance
- Wireless headphone demonstrations where available
- TV listening system advice
- Ongoing after-sales support
Contact your local Audio T store if you would like us to check whether your headphones are compatible with the BTA1 or help you choose a complete wireless TV listening system.