Open Source

Behold: F5-TTS, a flow-matching TTS model that clones a voice from a 5-second clip and runs on consumer hardware. No fine-tuning, no enrollment, no waiting. Plot twist: it's MIT licensed.

The Setup

I tested it on a recording of my own voice for a Pipedrive call-back IVR experiment. The setup is genuinely just one pip install. On an M4 Mac it generates roughly 8x realtime.

pip install f5-tts

# inference — one command, one reference clip
f5-tts_infer-cli \
    --model F5TTS_v1_Base \
    --ref_audio aiden_ref.wav \
    --ref_text "Hi, this is Aiden from Rebuild Relief." \
    --gen_text "Your hail damage assessment is scheduled for Tuesday."

The Money Pattern

The Python API is the move if you want to batch this — say, generating personalised voicemail drops from a Pipedrive deal list. Wrap it in a FastAPI endpoint and call it from a Netlify function.

from f5_tts.api import F5TTS
from pathlib import Path

tts = F5TTS(model="F5TTS_v1_Base")

def clone_voice(ref_wav: Path, ref_text: str, line: str, out: Path):
    wav, sr, _ = tts.infer(
        ref_file=str(ref_wav),
        ref_text=ref_text,
        gen_text=line,
        nfe_step=32,        # quality vs speed dial
        cfg_strength=2.0,
        speed=1.0,
    )
    tts.export_wav(wav, str(out), sample_rate=sr)

clone_voice(
    Path("aiden_ref.wav"),
    "Hi, this is Aiden from Rebuild Relief.",
    "Just confirming your roof inspection for Tuesday at 10am.",
    Path("out.wav"),
)

The Catch

Full quality is English and Chinese only. The community fine-tunes for other languages exist but you can hear the seams. If you're shipping Spanish voiceover, this isn't ready.

Also: zero-shot cloning from 5 seconds is a deepfake-shaped footgun. Consent in writing, watermark your outputs, and don't be the protagonist of a news article.

The Verdict

For English voice work where you control the reference audio, F5-TTS is the best free option in the game right now. The fact it runs on my laptop without a CUDA dance is the part that makes it actually useful. Clone tonight, ship tomorrow.