Auracast

Auracast Broadcast Audio

Auracast is the Bluetooth SIG's brand name for LC3 codec and Auracast." data-category="LE Audio">LE Audio broadcast audio, built on BIS (Broadcast Isochronous Stream) and Periodic Advertising. It enables public and private audio sharing scenarios that were impossible with Classic Bluetooth.

How Auracast Works

An Auracast broadcaster sets up a BIG (Broadcast Isochronous Group) containing one or more BIS streams encoded with the LC3 codec. It then announces the broadcast via Extended Advertising and advertising/" class="glossary-term-link" data-term="Periodic Advertising" data-definition="Connectionless data broadcasting at fixed intervals." data-category="GAP & Advertising">Periodic Advertising, which carry metadata such as the broadcast name, language, and program information.

Nearby receivers scan for Auracast sources, display available broadcasts to the user, and synchronize to the selected stream. If the broadcast is encrypted, the receiver must obtain the Broadcast Code -- typically via a QR code, NFC tap, or on-screen prompt.

Key Scenarios

Auracast addresses several categories of audio use cases:

• Public venues: Airports, train stations, gyms, and bars can broadcast flight announcements, workout music, or live sports commentary that patrons receive on their own earbuds
• Assistive listening: Replaces T-coil hearing loops in theaters, classrooms, and houses of worship with a digital, high-quality alternative
• Personal sharing: Users can share their podcast or music with a friend's earbuds by creating a personal Auracast broadcast
• Multi-language: A single venue can broadcast multiple language tracks simultaneously as separate BIS streams, each with language metadata for automatic selection

Ecosystem Status

Android 15 and iOS 18 include Auracast receiver support. Several hearing aid manufacturers have shipped Auracast-compatible devices. On the infrastructure side, Auracast transmitter hardware is available from companies like Sennheiser and Bose Professional. BLE SoCs supporting Auracast include the nRF5340, nRF54H20, and Qualcomm QCC series.

Deployment Considerations

When deploying Auracast in a venue, coverage depends on TX Power and antenna placement. A single transmitter with +10 dBm output covers roughly 30-50 meters indoors. For larger spaces, multiple synchronized transmitters or a Bluetooth Mesh relay architecture may be needed.