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ZDNET’s key takeaways

• Bluetooth dual device connectivity, aka “multipoint,” isn’t an official feature or spec.
• It’s an application of Bluetooth technologies, and each manufacturer wields it differently.
• Further migration from Bluetooth Classic to LE Audio promises improvements.

Bluetooth multipoint is a key selling point used by headphone and earbud manufacturers to entice consumers. This feature allows one pair of headphones to maintain individual connections with two (sometimes three) devices and switch audio between them without manually unpairing and re-pairing devices.

Also: What is Bluetooth 6.0? How the latest standard fixes audio problems we’d learned to live with

However, this feature can be unreliable, disconnecting from the device you want to stay connected to or injecting audio from the device you don’t want to hear. There’s a reason for this inconsistent behavior: multipoint, as presented to consumers, isn’t an official feature or specification of Bluetooth. The term is mostly marketing-speak.

I spoke with Henry Wong, director of market development at Bluetooth SIG, to understand how multipoint works, how it doesn’t, and whether further shifts from Bluetooth Classic to LE Audio can address its shortcomings.

How does Bluetooth multipoint work?

If a manufacturer allows for it, many headphones and earbuds can maintain a simultaneous connection with two source devices, such as a smartphone and a laptop. These are individual, one-to-one Bluetooth connections, but you can alternate between the two without disconnecting and reconnecting your devices.

This feature is often called Bluetooth multipoint, but since it’s not an authorized Bluetooth feature, there’s no official name for it, which is why Apple calls it Seamless Device Switching.

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“[Bluetooth multipoint] is not a specification,” Wong says. “Multipoint is an application of Bluetooth features that manufacturers are building on top of the Bluetooth toolbox, if you will.”

To further understand Bluetooth multipoint connectivity, you need to understand Bluetooth profiles. As Wong explains, you can think of Bluetooth as a giant toolbox, and profiles as the tools inside. 

Manufacturers can choose which Bluetooth profiles, codecs, and features to implement in their devices, and each profile serves a different wireless function. A wireless mouse and wireless earbuds don’t need the same profiles.

Bluetooth-enabled headphones generally support a number of profiles:

• Handset Profile (HSP): Enables basic wireless functionality between headphones and a source device.
• Advanced Audio Distribution Profile (A2DP):  Enables wireless stereo audio streaming.
• Hands-Free Profile (HFP): Enables wireless two-way voice calling.
• Audio/Video Remote Control Profile (AVRCP): Enables headphones acting as a wireless remote to control audio play/pause and volume on your paired device.

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Say you have a pair of headphones connected to both your laptop and phone. While using the headphones to watch YouTube on your laptop, A2DP and AVRCP are active. Then you get an incoming call on your phone, and your headphones should prioritize HFP to answer it. 

However, a frustrating example is watching YouTube on your laptop with headphones, only for your connected smartphone to interrupt your video every time you get a notification. Notifications can trigger HFP, briefly interfering with your stream. This interruption isn’t a bug; it’s simply how the Bluetooth technology works.

Why is multipoint sometimes unreliable?

Since Bluetooth multipoint isn’t an official Bluetooth feature, but rather an application of Bluetooth profiles, how these profiles interact is up to manufacturers. For example, if you have a pair of Sony headphones connected simultaneously to a Lenovo laptop and an iPhone, it’s unclear how the headphones decipher which connection to prioritize.

An incoming call will trigger the HFP to ring your phone’s ringtone in your ear. Staying connected to your phone while answering the call, or automatically disconnecting and reconnecting to your other media player, is where it can get tricky, and where differences across manufacturers are to blame.

Also: I connected a Bluetooth Auracast receiver to my TV, and it’s a worthwhile home audio upgrade

“If you buy Brand A headphones, Brand B laptop, and Brand C tablet, those are different manufacturers, different Bluetooth chipsets, and different Bluetooth stack applications,” Wong says. “So, being able to switch between them isn’t consistent, in most cases.”

A mismatch in your intention and your headphones’ behavior can be attributed to simply mixing connectivity between three different manufacturers, none of which optimize Bluetooth for the other’s devices.

“Depending on your headset, how it manages logic and the priorities of these different use cases is really up to the manufacturer,” Wong says. “That is why you can have inconsistency between these devices.”

Why device switching works in a closed ecosystem

Apple and Samsung have closed device ecosystems, and both stray from the term “multipoint,” instead opting for differentiated branding terms — Seamless Device Switching and Dual Audio, respectively. In these closed ecosystems, one manufacturer has complete control of how its devices communicate via Bluetooth.

“These companies do these [connection] transitions very well, and they don’t even call it ‘multipoint’ because it’s not really a feature, but it’s how they built it on top of the Bluetooth,” Wong says.

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This uniform level of control allows companies like Apple and Samsung to experience minimal friction, dropouts, and unreliability when switching Bluetooth connections. Like every other manufacturer, these connections use basic, standardized Bluetooth technologies for discovery and connection initiation, but proprietary tweaks to the user experience are the key, according to Wong.

“These are individual connections, but how they determine which one to switch to next is the moneymaker of this feature,” he says. “They have that magic behind the scenes to make it seamless.”

How LE Audio can help

The Bluetooth profiles used for multipoint connections rely on the Bluetooth Classic radio, the original version of Bluetooth connectivity that launched in the late 1990s. As an older technology, in a headphones context, it delivers poorer audio quality, less stable connections, and consumes more power than the Bluetooth Low Energy (BLE) protocol.

Since Bluetooth multipoint is not an official Bluetooth feature, there’s no replacement or direct improvement of it wrapped into BLE or LE Audio. However, the introduction of modern profiles, such as the Telephony and Media Audio Profile (TMAP) and Basic Audio Profile (BAP), succeeds A2DP, HFP, and HSP in improving connection transitions between phone calls and media playback, delivering higher fidelity, and reducing power consumption.

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Aside from committing to closed ecosystems, there aren’t any decisions consumers can make to guarantee a smoother multipoint experience. Bluetooth SIG has stressed this point throughout our conversations: Manufacturers have sole discretion over which Bluetooth features are available in a pair of headphones or earbuds, and their marketing materials typically don’t specify which profiles, which versions of those profiles, or how they work.

Consumers’ best hope is that manufacturers will continue to adopt LE Audio, not just BLE. BLE alone cannot stream audio, while LE Audio brings modern audio features, such as the LC3 codec, Auracast, and TMAP, that can better accommodate current complex audio streaming demands.