AutoMix and Open-Air Studios: Taming Crosstalk and Bleed
Open-air studios are a defining feature of Australian radio, from breezy harbour-front breakfast shows in Sydney to the laneway broadcasts that pop up during festivals in Melbourne's Federation Square. The relaxed format encourages banter and spontaneous conversation, but it also creates one of the toughest acoustic environments for a console operator. When multiple microphones share the same open space, every guest's voice bleeds into every other mic, and the result can sound like a crowded pub rather than a polished broadcast.
AutoMix is Lawo's answer to this long-standing problem. Built into the Power Core engine and accessible through the Ruby console range, the software applies real-time gain riding across multiple channels without a human operator riding faders. In environments where acoustic isolation is impossible, AutoMix becomes the safety net that keeps a programme on the air cleanly.
This article looks at how the algorithm behaves when wind, traffic, and overlapping conversation all arrive at the same microphone array, and what Australian broadcasters should know about configuring it.
The open-air studio challenge down under
Australian broadcasters have always leaned into the outdoor format. The ABC's regional breakfast shows, Nova's Bondi-based segments, and ARN's community events in Brisbane all rely on guests talking freely in spaces without soundproofing. Each setup introduces two distinct problems. The first is bleed, the unwanted pickup of one speaker's voice through a neighbouring microphone. The second is crosstalk, the broader acoustic coupling that turns a clean interview into a muddy echo chamber.
Australian speech adds another layer. Non-rhotic vowels, a wide pitch range swinging between casual drawl and sports commentary, and guests leaning in or away mid-sentence push the dynamic range wider than a typical European studio. Open-air setups at cricket grounds such as the MCG and the SCG expose microphones to wind gusts that can spike a channel by twenty decibels in an instant, while coastal broadcasts at Byron Bay or Manly must contend with surf noise sitting permanently in the lower midrange.
When a host and three guests share an outdoor table, the difference between intelligible audio and a wash of competing voices often comes down to how quickly the console can react. Manual fader riding cannot keep up with the rapid turn-taking that defines Australian talkback radio, which is the gap AutoMix is designed to fill.
How AutoMix detects and reduces mic bleed
AutoMix continuously analyses the energy and spectral content of every connected microphone channel and adjusts each gain in response to what the others are doing. When a channel registers a clear speech signal, the algorithm identifies the dominant speaker and attenuates the others proportionally. The threshold at which attenuation begins, the depth of that attenuation, and the release time after a speaker stops talking are all configurable from the VisTool interface.
The key to the system's effectiveness lies in weighted mixing logic. Each microphone can be assigned a priority value, allowing the host to remain at a fixed nominal level while guests duck automatically. In a five-person outdoor panel, the host's channel might be weighted at one, lead guests at zero point eight, and side participants at zero point six. AutoMix uses these weights to decide which channels stay loud and which drop back when conversation overlaps.
The algorithm keeps a small amount of ambient pickup so the broadcast still feels like a real space rather than a vocal booth. This balance matters for the relaxed Australian broadcasting style, where the venue itself contributes to the show's identity.
Tuning AutoMix settings for outdoor venues
Different locations call for different parameter sets, and operators who treat AutoMix as one-size-fits-all usually end up fighting it.
| Parameter | Conservative | Aggressive | Best Use Case |
|---|---|---|---|
| Attenuation depth | 6 to 9 dB | 15 to 20 dB | Quiet parks vs. noisy street broadcasts |
| Hold time | 0.8 seconds | 0.2 seconds | Slow interviews vs. rapid panel debates |
| Priority weighting | Uniform across mics | Host 1.5, guests 0.5 | Single anchor vs. free-form group chat |
| Ambient preservation | 20 to 25 dB below active | 35 dB below active | Coastal vs. indoor hybrid shows |
| Crosstalk threshold | Lower sensitivity | Higher sensitivity | Studio hybrid vs. outdoor festivals |
Coastal and harbour locations demand longer hold times to ride out wind-driven noise spikes, while festival stages with multiple hosts usually benefit from faster release times so the mix stays snappy. The numbers above are starting points rather than fixed values, and most engineers adjust them during sound check based on what the venue delivers. Channel grouping adds another useful layer, telling AutoMix to treat two mics as a single composite source when a host and sidekick regularly talk over each other.
Australian deployments and live workflows
Several Australian broadcasters have integrated AutoMix into workflows that previously depended on a dedicated audio operator riding faders throughout a programme. The change is particularly noticeable at community stations where staffing budgets are tight but production expectations remain high. A typical scenario involves a three-person breakfast team broadcasting from a sun-drenched deck overlooking a regional river, with AutoMix handling the inevitable cross-talk between host and newsreader as they swap segments every few minutes.
A larger example comes from a news radio operation that depends on Power Core for uplink reliability across remote sites. The Case Study: A News Radio Station Uses Power Core for Reliable Uplink describes how the same engine that supports AutoMix also carries the redundant network paths that keep regional bulletins on air during severe weather. The combination matters because outdoor broadcasting in Australia often coincides with conditions that strain both acoustics and infrastructure.
Operators report that AutoMix removes roughly seventy to eighty percent of the cognitive load associated with multi-mic outdoor shows. Instead of fighting crosstalk on every fader move, the engineer can focus on guest levels, on-air branding, and the small touches that define a station's sound.
Configurable mixing strategies for outdoor broadcasts
The flexibility of AutoMix becomes most valuable when the broadcast moves between locations. A morning show that begins in a controlled studio and walks out to a marquee for a live interview segment needs the system to adapt without a manual reset. AutoMix profiles can be stored as presets inside the Ruby console or the Power Core node, allowing the operator to recall a coastal configuration, an urban-street configuration, or a fully enclosed fallback with a single button press.
For larger events, such as a regional roadshow with a live audience, the same approach scales up. Multiple panel zones can be created, each with its own AutoMix instance, and the main console simply sums them together. The result is a coherent mix that sounds intentional rather than chaotic, even when a crowd of several hundred is cheering in the background.
The most useful next step is to run a one-hour AutoMix calibration session at your own venue during the next available sound check, recording both the raw and processed audio so you can A/B the difference directly.
