RS 275/255 - Before you start

The TV headphones were specially designed for long-form watching, giving you a fully immersive audio experience without disturbing others in the room. 

Unlike conventional headphones, they combine a dedicated feature set tailored specifically for use with televisions:

• stable long-range transmission
• clear speech enhancement
• low latency audio for perfect lip-sync
• easy plug-and-play connectivity. 

This combination ensures that you can enjoy your content in
high quality and with complete comfort, while keeping the environment around you quiet.

• Virtual Surround Sound – Creates a spacious, cinema-like listening experience.

• Speech Clarity – Enhances dialogue so voices are easier to understand.

• Hearing Profiles – Customize the sound to suit your individual hearing needs.

• Perfect Lip-Sync – Low-latency audio keeps sound and image seamlessly aligned.

• Reliable Connection for up to 50 m – Stable performance with long range, optimized for TV viewing.

• Up to 50 Hours Battery Life – Enjoy multiple TV sessions without recharging.

• All-Day Comfort – Lightweight design and soft ear cushions ensure enjoyable long-form viewing.

• Multi-Connectivity via Bluetooth Classic – The headphones connect effortlessly to TVs, tablets, mobile phones, and other Bluetooth devices.

• Auracast™ Broadcast Support – Transmit audio to an unlimited number of Auracast™-enabled headphones for shared or group listening.

The maximum volume depends on how you use the headphones.

When connected via Bluetooth Classic (e.g., to a smartphone or tablet), the headphones follow the standard Bluetooth output limit of up to 100 dB. However, when connected to the BTA1 TV Transmitter,
the system can deliver up to 106 dB.

This is a significant increase, as sound pressure does not increase linearly, but rather the decibel scale is exponential. 

This means that 106 dB is perceived as significantly louder than 100 dB, providing plenty of headroom for users who need higher volume levels.

• Hearing Profiles – Choose from four optimized profiles tailored to common hearing challenges, helping you to find the sound that fits your personal needs and preferences. 

Everyone hears a little differently; some people struggle with soft voices, others have trouble with high-pitched sounds, and some need loud sounds made gentler. 

Hearing profiles help to fix that.

• Noise Suppression – Reduces distracting background noise by blending stereo into mono, making dialogue clearer and easier to follow.

• Speech Clarity – Enhances voices and amplifies dialogue while maintaining full stereo sound, ensuring improved intelligibility without losing the immersive experience.

• High Maximum Volume (up to 106 dB) – Provides extra volume headroom when used with the transmitter, supporting users who require higher listening levels.

• Left/Right Balance Control – Adjust the audio levels for each ear individually to match your personal listening preferences.

Yes, absolutely.

The headphones work perfectly right out of the box—no app required.
 

However, the app unlocks several valuable additional features, including:

• Hearing profiles

• Noise suppression

• Left/right balance adjustment

• Privacy encryption settings

• Additional customization options

The app is also essential for keeping both the headphones and the transmitter up to date, as firmware updates can only be installed through the app.

So, while the headphones work on their own, the app provides the full feature set and the best possible experience.

Yes, you can choose between two options.

• Private listening:
You can mute the TV speakers and listen only through your headphones. In this mode, you control the volume directly on the headphones, so you can watch TV without disturbing others.

• Shared listening:
You can also leave the TV speakers on. In this case, the volume of the TV speakers and the volume of the headphones are completely independent of each other, so others can listen at their preferred volume while you can freely adjust your volume.

This flexibility makes the system ideal for both watching TV alone
and watching TV together. If the TV speakers do not remain on, refer
to the troubleshooting guide here.

The bundle of the RS 275 TV headphones also includes a headphone stand.

Yes, supplemental headphones (= HDR 275/255TV Headphones) are
available in the accessories section.

Please note that for the best possible TV experience, we recommend
using the headphones with the included transmitter. 

Additional headphones are ideal if you want to connect multiple headphones to a single transmitter.

1. Turn on your TV. 

It needs to be powered on before you start.

2. Power on the transmitter. 

Connect it to your TV (or another USB power source) using the USB C to USB A cable.

3. Establish the audio connection. Use the optical cable to link the transmitter's Optical Into your TV's Optical Out.

No optical output? 

Use the included analog cable or your own HDMI cable, depending on what your TV supports.

1. Make sure the TV transmitter is powered on and receiving an audio signal.  

The SOURCE LED should be solid (not flashing) and may appear blue, white, or orange depending on the audio source.

2. Follow the pairing instructions for your headphones. 

This is usually done via app or the Bluetooth settings.

▷ Connect the transmitter to your TV (power + audio) as shown in the instructions here. 

▷ Turn on the headphones using the power button.

▷ Wait 5-8 seconds. Both devices will automatically search for each other and pair.

▷ Wait for the voice prompt “Connected” to confirm a successful connection.

▷ If the connection fails, please refer to the troubleshooting guide here.
 

▷ Connect the transmitter to your TV (power + audio) as shown in the instructions here. 
 

▷ Turn on the headphones using the power button.

▷ Wait 5-8 seconds. Both devices will automatically search for each other and pair.

▷ Wait for the voice prompt “Connected” to confirm a successful connection.

▷ If the connection fails, please refer to the troubleshooting guide here.
 

The RA 255 (left, above) does not include the mounting stand.

The RS 275 (right, above) Does include the mounting stand.

The cables included in the box are sufficient for the majority of TVs. You can set up power and audio using the provided USB A to USB C cable, optical cable, and analog cable. 

If you prefer to connect the transmitter via HDMI-ARC, this is also possible, as the transmitter has an HDMI port. However, an HDMI ARC compatible cable is not included. 

HDMI-ARC Cable Information 

• Only cables labelled “with Ethernet” support ARC. 

• For best performance, we recommend a “Premium high-speed HDMI cable with Ethernet”. External USB Power (Optional) 

• The transmitter can be powered directly from any USB port on your TV using the included cable. 

• You may also use an external USB power adapter with a 5V output, but it's not required.

The RS 255 TV Headphones will automatically connect to the first previously known BTA1 TV Transmitter.

 To switch to a different transmitter, use the Auracast™ wizard in the Sennheiser Smart Control Plus App.

For BTA1 TV Transmitter:

LED SOURCE Operating state- 

• Off 
  Switched off, standby mode or no audio source available
• Flashes green
  Pairing with smartphone (for connection to Smart Control Plus app)
• Flashes white 3x
  Audio source HDMI-ARC selected
• Lights up white
  Audio source HDMI-ARC active
• Flashes light blue 3x
  Audio source TV AUDIO (analog/digital) selected
• Lights up light blue
  Audio source TV AUDIO (analog/digital) active
• Flashes orange 3x
  Audio source USB Audio selected
• Lights up orange
  Audio source USB Audio active
• Flashes continuously white/light blue/orange
  No audio input detected, searching for audio source
• Lights up red 
  Unsupported codec
• Flashes red 
  Error while charging headphones
• Lights up white for 1 second
  Reset to factory default settings

For the TV headphones (HDR 275/255):

LED Operating state-

• Off 
  Switched off, standby mode or reset
• Lights up white for 2 seconds 
  Switch-on process
• Flashes red 3x 
  Switch-off process
• Flashes blue and white alternatively for 120 seconds
  Pairing mode
• Flashes red and white alternatively 1x
  Pairing failed
• Flashes red 2x
  Connection to Bluetooth device lost
• Flashes white 10x repeatedly
  Incoming call
• Lights up red 
  Active call
• Lights up purple 
  Hearing enhancement is activated
• Pulses red Active charging: 
  Battery charge 0% to 10%
• Pulses yellow Active charging: 
  Battery charge 20% to 90%
• Pulses green Active charging: 
  Battery charge 90% to 100%
• Lights up red 3x 
  Charging fault
• Lights up red (when querying battery status)
  Battery indication: Battery charge 0% to 10%
• Lights up yellow (when querying battery status)
  Battery indication: Battery charge 10% to 60%
• Lights up green (when querying battery status)
  Battery indication: Battery charge 60% to 100%

You can connect the BTA1 TV Transmitter via any other available audio output on your TV. 

Make sure to select the correct output in your TV's audio settings. Some TV and soundbar combinations automatically prioritise the HDMI-ARC connection. 

In this case, we recommend connecting the TV transmitter to the HDMI-ARC port and the soundbar to the digital optical output.

Most PCs can be connected using either a USB cable or a 3.5 mm analog audio cable. 

Your computer will recognise the TV transmitter as an additional audio device.

You can connect the transmitter to your AV receiver using one of the following methods: 

• Digital Audio (recommended):

 Use an optical TOSLINK cable to connect the AV receiver's Optical Out to the transmitter's Optical In. 

• Analog Audio:

 Use a 3.5 mm analog audio cable from the transmitter to the headphone output or analog audio output of the AV receiver. 

If your AV receiver uses RCA outputs:

 Some receivers only provide red/white RCA audio outputs. In this case, you will need an RCA-to-3.5 mm converter, which can be purchased separately.

Each transmitter uses Frequency Hopping Spread Spectrum (FHSS) technology to ensure coexistence with Wi-Fi and other Bluetooth devices. 

In practical terms, around 10 to 20 transmitters can be used in parallel without any noticeable interference or audio dropouts.

Theoretically, an unlimited number of Auracast™ headphones can be connected to a single TV transmitter. 

In practice, a transmitter can typically support between 200 and 500 headphones while maintaining good performance.

No, only Auracast™-capable headphones are compatible with the BTA1 TV Transmitter.

Yes, the RS 275/255 TV Headphones are compatible with virtually every TV with an audio output. 

The package includes a digital optical cable (TOSLINK) and an analog 3.5 mm audio cable (AUX), allowing you to connect to the most common audio outputs. 

The BTA1 TV Transmitter also has an HDMI-ARC port for TVs that support it. Please note, however, that an HDMI-ARC cable is not included.

The range is up to 50 metres. Actual performance may vary depending on the environment—for example, obstacles such as walls or furniture, as well as a large number of Wi-Fi devices in the vicinity, can reduce the effective range.

The BTA1 TV Transmitter is certified to the HDMI 1.4b standard, including ARC capabilities. TVs with HDMI 1.4b certification or higher are compatible.

• Speech Clarity – Enhances vocal frequencies so that spoken words in dialogues, podcasts, calls, or videos are easier to understand. 

• Hearing Profiles – Choose from four optimized profiles tailored to common hearing challenges, helping you to find the sound that fits your personal needs and preferences. 

• Noise Suppression – Reduces background noise such as humming, fan noise, or ambient noise to produce a clearer audio signal. 

• Left/Right Balance Control – Allows you to shift the audio level between the left and right channels to match your preferred stereo balance. 

• Mono Downmix – Combines stereo channels into a single mono signal so that all audio content is equally audible from both sides. 

• Equalizer – Allows you to adjust specific frequency bands (bass, midrange, treble) to tailor the sound to your preferences.

The transmitter’s sound modes adjust the sound for all connected devices and shape the overall sound for all listeners. For example, you can choose “Virtual Surround Sound” for an immersive experience, “Speech Clarity” to highlight dialogue, or a Combination Mode that combines both. 

In contrast, the headphone modes allow each listener to customise their own sound without affecting others. Using the app, you can fine-tune your experience with hearing profiles, equalizer settings, speech clarity, noise suppression, and other features to make the sound pleasant and clear for you personally.

This feature improves the intelligibility of dialogue by emphasising the frequency ranges of human speech. An equaliser amplifies the parts of the audio signal where voices are most clearly audible, while keeping the overall sound balanced and immersive so you can still enjoy the full richness of music, effects, and ambience.

When using USB C audio, the connection focuses on PC audio, where no additional processing may be required. For this reason, sound modes and digital signal processing are bypassed in this mode.

If the sound doesn't feel quite right, try the following: 

▷ Adjust the volume directly on your headphones to your preferred level. 

▷ If necessary, also adjust the volume on your TV. 

▷ Open the audio settings of your TV and make sure that the “Audio Volume” is set to 80% 

▷ Open the Smart Control Plus app and check the TV transmitter's “Normalize Volume” setting. Turn it on or off to find the optimal volume.

The HDR 275 headphones can be connected to a variety of devices, such as mobile phones, tablets, or computers via Bluetooth Classic. This allows you to use them not only with your TV, but also for listening to music, making phone calls, or other audio applications, just like any regular Bluetooth headphones.