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Sesame CSM-1B

Apache-2.0; gated Llama dependency

The conversational speech model behind the viral Maya demo

CSM-1B is the open model from Sesame, whose 'Maya' assistant demo went viral for sounding uncannily present — breath, hesitation, tone shifts and all. It generates speech conditioned on conversation context, so replies sound like part of a dialogue rather than isolated lines. The open release is the base generation model behind that demo.

Hear Sesame CSM-1B

Sesame CSM-1B · Context-conditioned · Same three scripts across the directory.

Run it yourself

Best for: The conversational speech model behind the viral Maya demo

Commercial conditions: The release requires access to Llama-3.2-1B and uses Mimi. CSM’s Apache declaration does not replace the tokenizer/base-access agreement or codec terms. Reference voices also require permission.

Code: Apache-2.0. Weights: Apache-2.0 tag; gated Llama dependency. License sources checked 2026-09-20. Source 1Source 2Source 3

Before you choose: Compare the samples with your own use case. Check the linked documentation for code, weight, and voice license terms.

Details awaiting a fresh review. Hardware figures are estimates unless a benchmark is linked.

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Voices

1 voice
Neutral
Context-conditioneddefault
—

The scripts

Neutral
“The quick brown fox jumps over the lazy dog near the riverbank.”
Emotional
“I can't believe you actually did it. This is incredible!”
Numbers & Dates
“On March 14th, 2025, the team raised $4.2 million at a 38% margin.”

Run Sesame CSM-1B

git clone https://github.com/SesameAILabs/csm

Sources & setup details

Sesame CSM-1B FAQ

Do I need a GPU to run Sesame CSM-1B?

The directory lists roughly 8 GB of VRAM as a historical estimate. Check the model documentation for your checkpoint and runtime.

Can Sesame CSM-1B clone voices?

Yes — Sesame CSM-1B supports voice cloning from reference audio.

What license is Sesame CSM-1B released under?

Sesame CSM-1B is released under the Apache-2.0; gated Llama dependency license. Always check the repository for the exact terms — some models license code and weights separately.

What languages does Sesame CSM-1B support?

Sesame CSM-1B supports English.

Is there a hosted Sesame CSM-1B API?

OpenSpeech Cloud is accepting production-access interest for Sesame CSM-1B, but this model is not currently hosted in Cloud. Use the official repository for current deployment options.