Choosing a Replica (the face + voice)

Pick the right Replica (face + voice) for your AI Avatar. Stock vs your own, what you can change later, what you cannot.

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A Replica is the face and voice of your avatar. The same Replica can power many different personas. Picking the right Replica matters because — unlike the System Prompt — it isn't easy to change later: a "Sofia" persona feels like Sofia forever.

Stock avatars vs your own

You have two paths:

Use a stock Replica — ready in seconds. We have a library of professionally trained faces with built-in voices. Good fit for: customer-facing avatars where the founder doesn't want to be on camera, generic explainer videos, multilingual content where finding a matching voice matters more than a specific face. Train your own Replica — record a short training video of yourself, wait around 30–60 minutes for processing, and now there's an avatar that looks and sounds like you. Good fit for: personal brands, founder-led companies, course creators, sales reps who want to scale their reach.

Voice considerations

The voice comes with the Replica. You set it when the Replica is created (for your own) or it's baked in (for stock). You can't swap the voice on a persona-by-persona basis — if a persona needs a different voice, it needs a different Replica.

If your audience speaks a non-English language and you train your own Replica speaking that language, the resulting voice will sound natural in that language. A stock English-trained Replica trying to speak Romanian will sound mechanical.

What you cannot change after training

Face — the lip-sync, eye contact, and movement style are baked in by the training video.
Voice timbre — locked to whatever voice was paired with this Replica.
Background / lighting style — controlled by the training video you submitted. Re-train if you need a different look.

What you can change anytime

The System Prompt — completely different personality, no re-training.
The language — same Replica can speak many languages with varying naturalness.
Greeting, Knowledge Base, Objectives, Guardrails, Pronunciation — all swappable per persona.

How to pick

Public-facing brand? Pick a stock Replica that matches your brand tone. Switching later is jarring for repeat visitors.
Personal brand / founder? Train your own — your face is part of the product.
Internal-only or test persona? Use any stock Replica. The "wrapping" matters more than the face.

Try 2–3 stock Replicas with the same System Prompt before committing. The same words feel very different coming from a different face — sometimes the persona snaps into place when you change the face.