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Audio faults are almost always carrier or transport problems, not agent configuration. Establish which of the three symptoms you have before changing settings.

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First, classify the symptom

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Choppy or stuttering agent audio

1

Raise buffer size

On the Languages tab, increase Buffer Size. Values between 150 and 250 work for real-time conversation; lower values start playback sooner but break up under any jitter.
2

Check whether it correlates with a provider

Compare recent calls in Call history. If choppiness clusters on one telephony provider or one destination country, it is a carrier issue — see Choose a telephony setup.
3

Try a lower-latency voice model

Heavier TTS models are more sensitive to timing. A turbo or low-latency model from the same provider usually removes the stutter.
Raising buffer size trades delay for smoothness. If callers then complain the agent is slow to reply, you have moved the problem — see Responses feel slow.

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One-way audio

One-way audio on a bring-your-own-trunk setup is nearly always media negotiation. Work through:
1

Verify the trunk is registered and reachable

Re-check the trunk against Set up and register your trunk.
2

Confirm media is allowed in both directions

Firewalls that permit SIP signalling but not RTP produce exactly this symptom. Open the media ports your SBC uses, in both directions.
3

Check codec overlap

If the two sides share no codec, the call connects and stays silent.
4

Test the same agent on a Bolna-managed number

If audio is clean there, the agent is fine and the trunk is the variable. See Place calls on your trunk and Receive calls on your trunk.

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Background noise, not audio faults

If callers complain the agent’s line “sounds noisy”, check whether ambient noise is enabled on the Call tab — it plays a background track deliberately, and is available on Plivo and Vobiz telephony. Set it to None to remove it.

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What to collect before contacting support

  • The execution_id of two bad calls and one good one
  • The telephony provider and destination country
  • Whether the fault is inbound, outbound, or both
  • For SIP trunks, a SIP trace covering the failing call
Then reach out through Get help.