AES67 Network Audio Standard
AES67 defines a standard profile for transporting professional audio over IP networks using RTP (Real-time Transport Protocol) and PTP (Precision Time Protocol) for synchronization. Published in 2013, AES67 enables interoperability between proprietary audio-over-IP systems: Dante (Audinate), Ravenna (ALC NetworX), and SMPTE 2110-30 video-production systems can now exchange audio streams if configured in AES67 mode.
Dante devices with firmware 4.0+ support AES67 mode, allowing a Dante interface to transmit/receive standard RTP audio streams alongside proprietary Dante traffic. This flexibility makes AES67 critical for heterogeneous AV networks where multiple vendors' equipment coexist.
Key Specifications
RTP Payload: PCM audio encapsulated in RTP frames with standard headers (sequence number, timestamp, SSRC). Sample rates 48, 96, 192 kHz; bit depths 16–32 bits; mono or multichannel (up to 8 channels per RTP stream typical).
Clock Synchronization: PTP (IEEE 1588v2) for sub-microsecond accuracy across endpoints. Every talker and listener derive audio clock from the same Grandmaster clock; receivers reconstruct sample clock from RTP timestamps locked to PTP.
Transport: UDP/IP over Ethernet, typically on separate VLAN from IT traffic. Multicast addressing (239.x.x.x) for talker/listener discovery via SDP (Session Description Protocol).
SMPTE 2110-30 Alignment: AES67 shares RTP and PTP foundation; SMPTE 2110-30 extends for professional broadcast video + audio + metadata on the same network.
IGMP: Internet Group Management Protocol allows receivers to subscribe to multicast groups; managed switches support IGMP snooping to prevent flooding.
Practical Application for AV
AES67 bridges vendor silos. A live concert venue with Dante digital consoles and Ravenna-based video transport can now configure the Dante network to emit AES67 streams that video system receives natively.
Common scenarios:
- Hybrid Dante + Ravenna: Theater with Dante console feeding video control rack via AES67 mode; single managed network carries both.
- Broadcast interop: Multiple broadcasters contribute audio via AES67-compatible devices; one facility ingests and routes multivendor streams.
- Scalability: Larger venues can use multicast redundancy (send one stream to multiple listeners) without duplicating traffic per receiver, unlike Dante's unicast.
- IT integration: AES67 RTP is analyzable with standard IP tools (Wireshark); easier network troubleshooting than proprietary Dante protocol.
Integration with dante is seamless: set Dante device to "AES67 mode" in Dante Controller and it participates in multicast audio transport. See av-over-ip, dante-vs-aes67, and vlan-configuration-for-av for deployment details.
Disadvantage: AES67 lacks Dante's tight latency guarantees and automatic failover. Manual configuration (multicast addresses, SDP) is more complex than Dante's plug-and-play. Use AES67 when vendor diversity or broadcast standards compliance is essential; use Dante for pure-Dante or legacy systems.
Common Pitfalls
- Multicast flooding: IGMP snooping disabled on switch; multicast floods all ports, congesting non-AES67 network segments. Enable IGMP snooping and verify group subscriptions.
- PTP grand master missing: No PTP source clock on network; endpoints fail to sync or derive clock from best-effort IP, introducing jitter. Designate a master (Dante controller with PTP GM enabled) and verify all devices synchronize to it.
- SDP mismatch: Listener expecting 48 kHz mono; talker configured 96 kHz stereo. RTP flow exists but audio invalid. Pre-configure sample rates and channel counts on both sides.
- Dante mode confusion: Device in Dante-only mode doesn't transmit AES67. Switch to "AES67 mode" or "interop mode" in controller; verify in device menu.