Inside a Broadcast Audio Truck

A broadcast audio truck — also called an OB (outside broadcast) truck, production truck, or audio expando — is a mobile control room built into a semi-trailer. Inside, a self-contained audio department mixes every microphone, instrument input, playback source, and IFB feed for a live production, then hands the finished stems to the video truck and the transmission chain.

The truck exists because the show is somewhere the studio isn't: a stadium, a festival field, a red-carpet arrival, a benefit concert. Everything a mix engineer would find in a purpose-built broadcast facility — console, monitor path, comms matrix, redundant power, MADI/Dante fiber infrastructure — is duplicated inside a truck that can be parked, cabled, and calibrated in a single overnight load-in.

Mix A1 — the broadcast mix engineer

The A1 sits at the console and is responsible for the final broadcast mix. On a music show that means balancing band inputs, vocals, audience mics, playback, and effects into a polished 5.1 or immersive stem. On a sports or event broadcast it means blending announce positions, effects mics, natural sound, and packages so the story stays intelligible from kickoff through post-game.

Truck EIC — engineer in charge

The Truck EIC owns the technical integrity of the vehicle. They power the truck up, tie in generator or shore feeds, terminate incoming fiber, configure the router and network, coordinate MADI/Dante/AES67 patches with the video truck, and stay in the pocket during the show to troubleshoot anything that touches signal, power, or transport. When something breaks at air, the EIC is the person fixing it.

Pro Tools operator — playback & multitrack

The Pro Tools operator runs playback, multitrack record, and virtual soundcheck. On music shows they fire backing tracks, click, and sample content locked to timecode; on broadcast events they capture every input to isolated tracks for post, and can rebuild yesterday's mix from disk for rehearsal or fix-it-in-post sessions.

Stage A2 — the stage engineer

The A2 is the A1's counterpart on the stage or field of play. They deploy microphones, run snake and fiber to the truck, wrangle wireless RF coordination, and troubleshoot input problems in real time. On a large show there are often several A2s working under an A2 lead, each responsible for a zone — stage left, stage right, announce, playback, RF.

Communications (comms) engineer

The comms engineer builds and operates the intercom system that connects the director, producers, camera operators, stage managers, talent IFBs, and audio positions. Modern comms matrices route hundreds of endpoints — wired panels, wireless beltpacks, telephone interfaces, remote guests — and the comms engineer keeps every one of those conversations clean and cue-accurate.

How Orion and Gemini staff these roles

The truck determines how many of each position the show can carry. Orion is our compact 5.1 truck and staffs one Mix A1, one Truck EIC, one Pro Tools operator, and one Stage A2 — a single, tightly-coordinated audio department focused on a single broadcast mix.

Gemini doubles those seats. With its dual 7.1.4 Atmos control rooms and third Lawo router core, Gemini can staff two Mix A1 positions, two Pro Tools operators, and two Stage A2 zones in parallel — running two full immersive productions side by side, or splitting a single show into isolated music and broadcast mixes without stealing seats or resources from either.

Audio in a modern OB truck moves as digital packets far more than analog voltage. A typical signal flow looks like:

1. Capture. Microphones, DIs, and playback sources hit stage boxes that convert to MADI, Dante, or AES67 on fiber.
2. Transport. Redundant fiber runs carry hundreds of channels from the stage to the truck. Redundancy is not optional — a broken fiber cannot take a live show off the air.
3. Console. The A1's desk receives every input, applies dynamics, EQ, and effects, and produces the broadcast mix plus any auxiliary feeds — venue PA, monitor world, IFB, streaming stems.
4. Delivery. The finished mix goes to the video truck for embedding, to the transmission provider (satellite, fiber, IP), and to a set of confidence recorders for post.

Immersive broadcast — Dolby Atmos and 7.1.4 style deliveries — adds a height dimension to the mix. Inside the truck this means an additional monitoring layer (overhead speakers or a calibrated binaural rig), an object-based renderer alongside the main console, and a second set of stems that carry beds and objects separately from the traditional 5.1 or stereo path.

RPG runs this workflow on two purpose-built trucks. Our compact 5.1 truck, Orion, is the right tool for tight footprints and single-mix broadcasts where 5.1 is the deliverable. Our flagship, Gemini, is the only truck on the planet with two independent 7.1.4 Dolby Atmos control rooms under one roof, plus a third Lawo router core that routes thousands of audio paths between them — letting two full immersive productions run in parallel, or a single show carry a music mix and a broadcast mix in fully isolated environments.

Practically, the A1's workload roughly doubles on an immersive show: every input has a position, every effect has a trajectory, and the mix has to translate cleanly from a full Atmos playback back down to stereo for viewers on phones and TV speakers. Orion and Gemini are designed around that dual-deliverable workflow, not retrofitted onto a stereo desk.

• T-24h. Truck parks, generator ties in, cable ramps set. A2 crew runs fiber to stage.
• T-12h. Console patched, monitor rig calibrated, RF frequency coordination locked, comms matrix built.
• T-6h. Line check, then band or event soundcheck. A1 builds scenes, snapshots, and effects sends.
• T-1h. Broadcast integration — video truck confirms embed, transmission provider confirms path, cue-to-cue with the director.
• Air. A1 mixes the show. A2s troubleshoot inputs, wireless, and stage changes in real time. Comms engineer keeps the director's ear clear.
• Post-show. Confidence recordings archived, truck struck, cables coiled. Fly date tomorrow.

What's the difference between an OB truck and a production truck?

They're the same thing — "outside broadcast" is the UK/European term, "production truck" the US one. Both describe a mobile control room used for live remote productions.

How many people work in the audio department on a big show?

A large music broadcast can carry an A1, a music mixer, a broadcast mixer, two-to-six A2s, an RF coordinator, a comms engineer, and a systems tech. A sports remote is typically smaller — an A1, one or two A2s, and a comms engineer.

Do I need an immersive-capable truck for my show?

Only if you're delivering an Atmos or 5.1.4 mix. Stereo and 5.1 shows don't require an immersive truck — but immersive-capable trucks handle stereo and 5.1 without compromise, so producers planning a mixed slate often standardize on them.