nineninesix.ai

Voice AI engineering

How we build and run real-time text-to-speech in production: latency, streaming, GPU serving and integration with voice agent frameworks.

Engineering5 min read

How to fine-tune Gepard (and when not to)

Zero-shot cloning takes minutes and covers most cases. A LoRA fine-tune needs about 1 hour of clean audio, a full one needs 4 GPUs. Where each line falls.

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Engineering5 min read

Self-hosted TTS or an API: the crossover

The crossover sits near 290M characters a month, about 4,800 hours of audio. Below it the API wins on total cost, and the GPU bill is not the whole story.

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Engineering5 min read

Why Gepard runs on vLLM, and what it buys

One design rule shaped the whole model: it must run on stock vLLM without patching a single compute kernel. The result is 204x real time on one GPU.

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Engineering6 min read

How text to speech works, and how to choose

How modern TTS works, the 5 metrics vendors quote and which of them lie, and 8 questions to ask first. Why 200 ms of synthesis eats a whole latency budget.

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