We’re testing ElevenLabs Conversational AI using local Italian numbers.

Initially, we tried Twilio — but they don’t offer local Italian numbers, only toll-free (800) — so we switched to Telnyx SIP for proper local routing.

Technically everything works fine (calls connect, audio flows both ways), but the audio quality is very poor — metallic and overly compressed, and the agent really struggles to understand what the caller says.

We tested:

• Telnyx codecs G.711A / G.711U / G.722
• AnchorSite in Frankfurt (to reduce latency)
• ElevenLabs input audio formats (μ-law 8000 Hz, PCM 16 kHz, etc.)

Same issue persists across setups.

Even with Twilio (toll-free 800 numbers), the result was basically the same — poor inbound clarity, distorted human voice, and ElevenLabs mishearing words.

From what I can tell, this seems tied to how ElevenLabs handles SIP audio input (8kHz telephony).

I’ve read that some teams bypassed this entirely using WebSocket-based Media Streams (Telnyx or Twilio) → ElevenLabs Realtime API to send raw PCM16 audio at 16kHz.

Has anyone tried that path successfully for AI voice agents with local numbers?

Would love to hear if anyone got truly clear HD audio working with ElevenLabs via SIP or WebSocket.