voice agent
**Voice Agents and Real-Time Conversation**
**Voice Agent Architecture**
```
[User Speech]
|
v
[Speech-to-Text] (Whisper, Deepgram)
|
v
[LLM Processing] (GPT-4, Claude)
|
v
[Text-to-Speech] (ElevenLabs, OpenAI)
|
v
[Audio Output]
```
**Key Metrics**
| Metric | Target | Description |
|--------|--------|-------------|
| Latency | <1s total | Time from speech end to audio start |
| TTFB | <500ms | Time to first audio byte |
| Interruption handling | Immediate | User can interrupt agent |
**Real-Time API (OpenAI)**
```python
from openai import OpenAI
client = OpenAI()
# Real-time conversation API (conceptual)
session = client.realtime.create_session(
voice="nova",
model="gpt-4o-realtime"
)
# Bidirectional audio streaming
async for event in session:
if event.type == "audio_chunk":
play_audio(event.audio)
elif event.type == "transcript":
print(f"User: {event.text}")
```
**Latency Optimization**
| Strategy | Impact |
|----------|--------|
| Streaming STT | Start processing before speech ends |
| Streaming TTS | Start speaking before full response |
| Prefill responses | "Let me think..." while processing |
| Edge deployment | Reduce round-trip time |
| Speculative execution | Predict likely responses |
**Turn-Taking**
```python
class VoiceAgent:
def __init__(self):
self.is_speaking = False
self.vad = VoiceActivityDetector()
async def handle_audio(self, audio_chunk):
if self.is_speaking and self.vad.is_speech(audio_chunk):
# User interruption
await self.stop_speaking()
await self.process_interruption(audio_chunk)
```
**Use Cases**
| Use Case | Requirements |
|----------|--------------|
| Customer support | Low latency, empathy |
| Voice assistants | Fast, accurate |
| Interviewing | Turn-taking, follow-ups |
| Language tutoring | Pronunciation feedback |
**Platforms**
| Platform | Features |
|----------|----------|
| Vapi | Full-stack voice AI |
| Retell | Enterprise voice agents |
| ElevenLabs Conversational | Low latency |
| Hume AI | Emotion-aware |
**Challenges**
- Managing interruptions gracefully
- Handling noise and multiple speakers
- Cross-talk in phone calls
- Maintaining conversation context
- Latency across components