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🔊 Radios & Receivers

A receiver rebroadcasts a whole channel out of the actor it sits on: a radio, an intercom, a PA speaker, a walkie-talkie in someone's hand.

Drop the Proximity Voice Receiver component on any actor, set its Listen Channel, and every speaker talking on that channel is also heard from that actor, spatialized from there with its own attenuation, volume and effects. Nothing on other channels comes out of it.

Speakers keep emitting from their own body too, so someone standing next to the speaker hears them directly, and someone standing next to the radio hears them through the radio.

1. Add a receiver

  1. Open the actor Blueprint you want to turn into a radio (a prop, a wall intercom, a handheld device).
  2. Add the Proximity Voice Receiver component.
  3. Set Listen Channel to the channel it should pick up (see Channels).

That's it, it works as soon as it's placed.

Note

The actor does not need to be replicated. Voice packets already reach every machine, and each machine decides locally what to play. Placing a radio in the level, spawning it client-side, or attaching it to a hand all work the same way.

2. Properties

Property Description
Listen Channel Only speakers on this channel come out of this receiver. Everything else is ignored.
Receiver Enabled Turn the receiver on or off. Off is silent and releases its audio immediately.
Output Configuration A ProximityVoiceConfig asset used for voices coming out of this receiver: attenuation, volume, source effects, occlusion. Leave it empty to use each speaker's own config.
Volume Multiplier Volume applied on top of the output configuration. Handy to reuse one config asset at several levels.
Attach Socket Mesh socket the voice plays from (e.g. a speaker grille). Falls back to the actor root.
Emitter Priority Used when the speaker's Emitter Selection is Priority. Defaults to 1, a speaker's own body defaults to 0.
Max Simultaneous Speakers Hard cap on how many speakers can come out of this receiver at once (1 to 16, default 4).

Note

Capture and jitter buffer settings are ignored in the Output Configuration, those belong to the speaker. Only playback-side settings apply here.

3. Make it sound like a radio

This is the whole point of Output Configuration: the same voice can be clean on the pawn and crunchy on the radio.

  1. Create a second ProximityVoiceConfig asset, e.g. DA_RadioReceiver.
  2. Give it a short Proximity Attenuation (a radio should only be heard in the room it's in).
  3. Assign a Source Effect Chain with your radio crunch, see Voice Effects.
  4. Assign that asset to the receiver's Output Configuration.

Tip

Occlusion is evaluated per emitter, from where each one actually sits. A radio behind a wall is muffled even when the speaker is standing in the open. See Occlusion.

4. When you can hear both at once

If you're close to the speaker and close to a radio rebroadcasting them, the same voice reaches you from two places. Playing both is not "twice as loud", it's one signal arriving at two distances, which comb-filters and sounds hollow.

That's what Emitter Selection on the speaker's ProximityVoiceConfig decides:

Mode What you hear
Loudest Wins (default) The emitter that reaches you loudest, the others fade out.
Priority The audible emitter with the highest priority, whatever the distance. Loudness breaks ties.
Mix All Every emitter plays. Expect comb filtering when two are audible at once.

Two more dials go with it, both on the speaker's config:

Property Description
Emitter Crossfade Time Seconds to fade between emitters when the winner changes. 0 = hard switch (audible click).
Emitter Switch Hysteresis How much louder a challenger must be to take over (0.1 = 10%). Stops the two swapping every frame at the crossover point.
Body Emitter Priority Priority of the speaker's own body, used in Priority mode.

Tip

Want the radio to always win, even when you're standing next to the speaker? Set the speaker config's Emitter Selection to Priority and give the receiver a higher Emitter Priority than Body Emitter Priority.

5. Events & getters

On the Proximity Voice Receiver component:

Node Fires / returns
On Speaker Started A speaker started coming out of this receiver. Gives you the Speaker actor.
On Speaker Stopped A speaker stopped coming out of this receiver.
On Receiver Activity Loudest voice on this receiver, every time it moves. 0 when silent.
Is Receiving Voice() True while at least one speaker is transmitting on this receiver's channel.
Get Received Voice Level() Loudest voice currently on this receiver's channel, 0 when silent.
Get Speakers On Air() The actors currently transmitting on this receiver's channel.
Set Listen Channel(int) Retune the receiver. Takes effect immediately, including mid-sentence.
Set Receiver Enabled(bool) Turn it on or off at runtime.

From the speaker side, on the Proximity Voice Chat component:

Node Returns
Get Active Receivers() Receivers currently rebroadcasting this speaker on the local machine.
Get Receiver Audio Component(Receiver) The Audio Component this speaker plays through on that receiver. Null while it isn't rebroadcasting them.

And on the Proximity Voice Chat Subsystem:

Node Returns
Get Receivers On Channel(int) Every receiver in the level currently rebroadcasting that channel.

Example: a walkie-talkie with a blinking light

  1. Put a Proximity Voice Receiver on your walkie-talkie actor, Listen Channel = 1.
  2. Assign DA_RadioReceiver as its Output Configuration (short attenuation + crunch chain).
  3. Bind On Receiver Activity and drive a light / material parameter with Volume.
  4. Bind On Speaker Started / On Speaker Stopped to play a click or a burst of static.
  5. Use Set Receiver Enabled for an on/off switch, and Set Listen Channel for a frequency knob.

Good to know

  • A speaker never hears their own voice come back out of a receiver, no feedback loop to worry about.
  • Receivers only hold a speaker while that speaker is actually transmitting. Slots are freed at the end of each talk burst.
  • Slots are first come, first served. A speaker who finds the receiver full is simply not rebroadcast, and still emits from their own body.
  • A speaker is rebroadcast even when the local listener is on another channel, that's the point of a radio.
  • Muting still applies. A locally muted or server-muted player doesn't come out of a receiver either.

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