AutoMix Ducking Thresholds for Frictionless News Inserts
Australian commercial radio stations from Sydney's Kings Cross to Melbourne's South Bank studios rely on automated mixing to keep presenters audible during rolling news bulletins. Networks such as ARN and Southern Cross Austereo handle dozens of hourly news inserts in their metro markets, and even a brief audio pump between an intro jingle and a voice report can erode listener trust. The clearest path to clean, predictable voice-over-news mixing on Lawo systems lives inside the ducking threshold controls of AutoMix.
AutoMix is the smart fader engine shared across Lawo's Ruby consoles and Power Core audio nodes, designed to balance multiple open microphones without an operator riding the faders. When configured for news insertion, threshold settings determine precisely how aggressively background program material dips the moment a newsreader speaks. Set too high, and bulletins fight the music bed; set too low, and the presenter's "good morning Brisbane" barely registers over the segue.
Radio in Australia operates across very different bandwidth realities, from the dense FM spectrum of Brisbane and Perth to community stations serving regional New South Wales. Local content windows around breakfast drive shows mean audiences expect every news bulletin to begin at the same perceived loudness and clarity they heard on yesterday's broadcast. Tuning ducking thresholds to that expectation is what separates a station that sounds confident from one that sounds busy.
The remainder of this guide walks through how the ducking threshold parameter behaves on AutoMix, the typical default values shipped with new firmware, and the practical adjustments broadcasters can apply when news cadence, voice level, or external feed angles change during a show. Engineers adopting Broadcast 3.0 architectures will recognise the workflow alongside Ruby surface layouts and VisTool custom controls.
How the ducking threshold parameter behaves
AutoMix continuously samples incoming microphone signals and compares their energy against a user-defined threshold measured in dBFS. Once a presenter crosses that line, the engine commands every other summed source, including music beds, ad breaks, and remote callers, to attenuate by an amount set under the ducking depth control. Reaction time and release time sit on either side of the threshold event, shaping how quickly the bed returns to full level after the bulletin ends.
In practical terms, the threshold acts as a gatekeeper rather than a hard on-off switch. A threshold of -24 dBFS, for instance, means that quiet asides or breath sounds rarely trigger ducking, while spoken consonants and full words always do. Lowering the threshold to -30 dBFS invites more sources into the dialogue, which can muddy the news read during crosstalk between co-hosts in a Perth newsroom.
Default settings and common pitfalls
Lawo ships AutoMix with conservative defaults that work across most talkback studios. A typical preset targets a threshold around -26 dBFS, a depth of -12 dB, and a release time of 800 milliseconds. Those figures favour protection against accidental triggering, but they can be too gentle for stations whose breakfast shows run six bulletins an hour against a high-energy music bed. Coordinating fixes across early and late shifts often relies on a shared shift coordination playbook so neither team second-guesses the other's tuning choices during a cross.
When the threshold reads too high relative to the presenter's mic level, operators often report that the first word of every bulletin arrives late, or that a tail of reverb from the music sweeps across the bulletin intro. Lowering the threshold three or four decibels solves the latency problem but exposes another risk: in studios with noisy HVAC systems or open-talkback mics, the ducking now triggers on background sound that was previously invisible to the engine.
| Threshold setting | Best suited to | Strength | Watch point |
|---|---|---|---|
| -22 dBFS | Loud music beds, high-energy pop stations | Crisp word starts | False triggering on studio rumble |
| -26 dBFS | Talk stations with steady music flow | Balanced behaviour | May clip very soft voices |
| -30 dBFS | Quiet newsreaders, drama inserts | Captures whispered cues | Susceptible to room noise |
| -34 dBFS | Multi-host panel discussions | Respects every mic | Bed barely ducks, loses presence |
Calibrating for Australian news cycles
ACMA licence conditions require clearly flagged news bulletins at predictable intervals, which puts a heavier workload on automated mixing at stations running ARN's KIIS network or the ABC's metropolitan services. Engineers should treat each news window as a calibration event: re-check the presenter's mic gain ahead of every bulletin, especially if the talent has moved away from the shock mount after a song link.
Sydney-based engineers frequently share a rule of thumb with their Melbourne counterparts - set the ducking threshold 8 dB below the presenter's normal speech level, then add 2 dB of headroom for shouted headlines during breaking stories. Brisbane studios running triple shifts benefit from saving these offsets as named presets inside AutoMix, so the morning producer can load "News Heavy" before the 6 a.m. bulletin and revert to "Daytime" afterwards.
Regional broadcasts from satellite-linked sites in Western Australia or Tasmania introduce delay that can confuse the sidechain. Adjust the threshold by listening to the sidechain cue rather than the studio monitor; doing so removes the delay from the perception of clipping and lets the engine react to actual voice energy rather than the return feed.
Linking ducking to Ruby and VisTool workflows
AutoMix settings live in Power Core, but operators control them through fader logic and soft buttons laid out on Ruby consoles. When a journalist is waiting in the green room and the producer needs to preview an incoming news wire, the surface can be configured so that holding a user button temporarily drops the threshold for cleaner line-up cues. That kind of contextual override keeps bulletins tidy without needing an engineer at the rack.
For larger installations, VisTool screens become the right place to visualise threshold behaviour in real time. Stations can build multitouch dashboards that plot every mic's instantaneous level against the threshold line, so producers see at a glance whether a co-host's laughter is triggering ducking mid-bulletin. The principle behind custom multitouch control surfaces for radio shows how studios are extending these displays into the news booth itself.
A wider workflow becomes smoother when console recall and AutoMix presets are saved as a single snapshot. After a hot cross to a sports caller, for instance, the console can recall both mic routing and the "News Light" preset in one touch, sparing the operator from diving into menus while the bulletin is live.
Diagnosing pumping and tail bleed
When bulletins sound unnaturally compressed or the music bed slowly rises back after a newscast, the cause is almost always a release time that does not match the room. Stations covering cricket or AFL inserts in Melbourne often extend the release to around 1.2 seconds so the music swells gently under the sports report, while stations running shorter bulletins in Adelaide favour 500 milliseconds for snappier recovery.
Sidechain filtering solves another class of complaints. Routing only mid-band frequencies of the presenter mic into the sidechain prevents low-frequency rumble from an air-conditioning unit near the Perth bureau from triggering dips mid-read. Pair that filter with a slightly higher threshold, and the bulletin sits cleanly above the bed without pumping.
Local room treatment matters too. Studios with glass-fronted views over Sydney Harbour often suffer reflections that elevate the threshold floor, so engineers compensate by shifting the threshold down 2 dB and tightening the gate. Tracking these adjustments in a station-level log helps new operators understand why a particular newsreader's settings differ from the default.
Effective ducking threshold tuning is less about finding one magic number and more about matching the engine to the cadence of each market's news load. Stations running dense bulletin grids in capital cities will sit closer to -30 dBFS with short release windows, while regional broadcasters can afford the breathing room of gentler settings. Operators who treat AutoMix thresholds as show-by-show variables, checked alongside the presenter's mic calibration at the top of every hour, quickly stop hearing ducking altogether.
Begin tomorrow's shift by saving the current AutoMix threshold, depth, and release values into a dated scene on the Power Core, then run the first news bulletin of the day while listening only to the program feed.
