Event Tech
A browser on the local network
The offline dashboard provides configuration, gain control, status and access to route logs without depending on a cloud service.
ONE PROGRAMME.
CONNECTED SYSTEMS.
A one-way live-audio appliance for getting programme sound from one location to another. Shaped by the moving streets, changing sightlines and practical demands of carnival sound systems.
Explore the system ↓MONO PCM48 kHz / 16-bit audio
ONE WAYAnalogue input to analogue output
2014–2026Documented development programme
6.1.9Software-qualified in the supplied audit
+ The challengeKEEP THE SOUND.
KEEP THE SOUND.
LOSE THE DRIFT.
Several moving sound systems playing the same programme should feel connected. Dropouts break the experience. A link that quietly accumulates delay can leave the systems playing out of time.
Hedera Link grew from a 2014 request to connect carnival floats. Its focus is continuity with controlled delay: a clean link should stay responsive, absorb brief disruption and recover when the route opens again.
The challenge extends beyond the audio software. Antenna alignment, vehicle vibration, buildings, crowd density, radio configuration and operator decisions all affect the result.
+ How it worksANALOGUE IN.
ANALOGUE IN.
IP BETWEEN. AUDIO OUT.
A dedicated audio appliance at each end carries one-way, uncompressed programme audio over an IP network. The documented profile transports a mono programme from the transmit site to the receive site.
- 01 / Transmit
Capture the programme.
A line-level analogue input enters the transmit appliance. An explicitly wired audio graph connects capture, configured protection and the transport.
- 02 / Transport
Cross the link.
Ethernet connects the endpoints through an IP network. For the carnival use case, the last hop is a planned 5 GHz point-to-point radio link.
- 03 / Receive
Feed the next system.
The receiving appliance reconstructs the mono programme and supplies analogue line output. Feeding both playback ports does not turn the transport into stereo.
+ Built for the operatorLOCAL CONTROL.
LOCAL CONTROL.
HONEST STATUS.
Audio evidence, not just a ping
Network reachability, local audio readiness and actual media flow are different signals. The 6.1.9 audit describes true / false / unavailable media-flow reporting, rather than treating missing evidence as a healthy zero.
Identity and pairing
A receiver must connect to the transmitter on its own radio hop. Expected-peer identity checks help identify the wrong appliance answering at a familiar address.
A record of the route
Append-only field logs retain configuration identity, status, operator marks and incidents. Monotonic timestamps help relate events within a unit even when its wall clock is wrong.
+ Delay with disciplineRESPOND TO THE STREET.
RESPOND TO THE STREET.
RETURN TO THE BASELINE.
The project’s clean-hop target is around 20–30 ms from transmitter input to receiver output. This is a design and acceptance target, not a guaranteed performance specification.
The field doctrine allows short-lived buffering under pressure, then calls for delay to recover as conditions improve. Persistent delay calls for an RF, route or pairing diagnosis; a larger queue cannot restore a lost path.
Freeze the audio configuration.
Restarting the audio engine or connection can interrupt the programme. The field workflow calls for configuration to be agreed before movement and for incidents to be logged during operation.
Keep the profiles distinct.
The software default and the proposed carnival operating profile are separate configurations. Both require matched endpoints and physical acceptance testing before deployment.
+ From the fieldDIAGNOSE THE FAILURE.
DIAGNOSE THE FAILURE.
THEN CHANGE THE RIGHT THING.
Right hop. Right partner.
A running service can still be connected to the wrong transmitter. Confirm peer identity and the path before changing buffers.
Follow the signal.
Check the audio card, input level, port wiring and configured protection. A reachable network does not prove the analogue path is passing audio.
Watch recovery.
Buffering should deal with transient arrival variation. Delay that grows and stays high needs investigation.
Respect the corner.
Alignment, height, occlusion and route geometry remain physical constraints. Software cannot invent line of sight.
+ A working historyTWELVE YEARS.
TWELVE YEARS.
ONE PERSISTENT QUESTION.
The brief becomes a prototype.
A request to link moving floats leads to self-funded exploration of audio over IP as a practical alternative to the available radio links.
The hidden-buffer lesson.
An early live run exposes delay accumulation. A from-scratch rebuild follows, with greater control over the audio and transport path.
Engineering beyond the codec.
The history records tuning, route-dependent RF behaviour, changing vehicle arrangements and a more formal technical description. Antenna mechanics and operational discipline become central.
Evidence before the next deployment.
The August campaign drives clearer failure categories, pairing checks and telemetry. NHC2027 / 6.1.9 is the documented software baseline, with physical acceptance still identified as outstanding in the supplied September record.
+ Documented statusWHAT IS ESTABLISHED.
WHAT IS ESTABLISHED.
WHAT COMES NEXT.
Software-qualified in the project record
The supplied audit reports 208 automated tests passing for build 6.1.9. This describes the supplied software record, not an independently repeated test on this website.
Audio continuity, recovery behaviour and radio performance remain subject to acceptance on the complete deployment system.
Radio planning remains part of the work
The supplied Ofcom pack is an enquiry about the intended 5 GHz hop, antenna gain, power and moving-vehicle use. It is not an authorisation or a statement of approval.
Future deployment depends on a confirmed operating plan, a frozen and matched system profile, and route testing with logged acceptance criteria.
+ About this overviewBUILT FROM THE
BUILT FROM THE
PROJECT RECORD.
This overview draws on the supplied technical white paper, project blog, full history, complete information pack, NHC2027 specification, field guide, carnival field paper and Ofcom enquiry pack. The source record dates from September 2026; development targets and unresolved questions are presented as such.
Source notes and documented differences
- Technical baseline: NHC2027 / 6.1.9, one-way mono, 48 kHz / 16-bit; configurable options do not establish a tested stereo product.
- Field dates: the 4 September project blog correction gives 30–31 August 2026. Earlier guide and field-paper dates differ.
- Latency: 20–30 ms clean-hop and recovery below 80 ms are acceptance aims in the operations material. A proposed 120 ms / 10 s stress flag is a later policy proposal, not a universal shipped threshold.
- Evidence limits: historic performance comparisons are not reproduced here as current specifications. Software tests do not substitute for physical audio and radio acceptance.
- Radio status: the Ofcom information pack records questions requiring confirmation; it does not establish approval.
Carnival image credits
Historic context imagery, not photographs of a Hedera Link deployment.
Jay Bergesen: DJing in a Truck and Sound System Set Up · Notting Hill Carnival, 2008 · CC BY 2.0. Cropped, graded to monochrome and darkened in this layout.
Carnival crowd artwork supplied in the design reference archive.
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+ Hedera Link / Research & collaborationLET’S PLAN
LET’S PLAN
THE NEXT HOP.
Discuss the route, the audio requirement and the evidence needed for the next stage of development.
Discuss Hedera Link ↗