Three Voice Agent Architectures and Why Speech Accuracy Is the Real Bottleneck

Voice agents follow a core loop of listening, reasoning, and responding, but the architecture chosen to execute that loop significantly affects latency, cost, and accuracy. The classic chained pipeline connects separate speech-to-text, large language model, and text-to-speech components, offering granular control at the cost of integration complexity. A newer speech-to-speech approach collapses all three stages into a single multimodal model, simplifying setup but sacrificing transparency and fine-grained tuning. A third unified architecture attempts to bridge both approaches, combining the simplicity of an integrated system with greater control over individual components. Across all three patterns, errors in the speech-to-text stage propagate downstream, making transcription accuracy the foundational constraint on overall agent quality.