What is Mean Opinion Score? (MOS)
2 min read · Bolcho
A 1-to-5 rating of how natural synthesized speech sounds, based on human listeners — the standard quality metric for TTS.
Mean Opinion Score explained
Mean opinion score averages listener ratings of audio naturalness. For voice AI, a high MOS means the agent's voice sounds like a person rather than a robot, which directly affects trust and completion rates.
Why it matters for voice AI in India
Understanding mean opinion score helps you build voice agents that actually work for Indian callers, genuine languages, low latency, and near-cost pricing. Bolcho is built around exactly these fundamentals.
See it in a real agent
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Frequently asked questions
What does Mean Opinion Score mean?
A 1-to-5 rating of how natural synthesized speech sounds, based on human listeners — the standard quality metric for TTS.
Why does mean opinion score matter in voice AI?
Mean opinion score averages listener ratings of audio naturalness. For voice AI, a high MOS means the agent's voice sounds like a person rather than a robot, which directly affects trust and completion rates.