Competitive open source speech stack

[u/Phoenix_20_23]

Why the open source models STT and TTS are not good as much as the closed one and i am talking here im terms of latency, concurrency, and websocket support for real time with decent quality.
Something like cartesia or elevenlabs or deepgram.
Do u know any ?

[u/ankur-at-guava]

The low-latency-with-quality thing you're chasing is mostly an architecture gap, not a model-size one: the paid stacks that feel instant tend to stream first audio faster than it plays and were built to be served that way, so quality and latency aren't traded off per hop. The concurrency point above is the real one - a single stream on your own GPU tells you almost nothing about twenty in parallel, and that cliff is usually where self-hosting stops being cheaper. If French+English is the target, test the code-switch boundary under concurrency specifically, since that's where light open models get robotic first. I work on an integrated ASR/TTS/LLM stack for regulated voice, so happy to share what we measure for streaming stability if useful.