Control variation with temperature

temperature sets how much a Paxa TTS Flash v2 reading varies from one request to the next, from 0 to 2. What it changes, designed voices, where it is read, and billing.

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temperature is a field of POST /v1/tts that sets how much a reading varies from one request to the next: its pacing, pauses, breaths, and melody. It runs from 0 to 2 and defaults to 0.5. Paxa TTS Flash v2 reads it.

curl -X POST https://api.paxalabs.com/v1/tts \
  -H "Authorization: Bearer $PAXA_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "text": "สวัสดีครับ ยินดีต้อนรับสู่ Paxa Labs",
    "voice": "khanomkrok",
    "model": "paxa-tts-flash-v2",
    "temperature": 0
  }' \
  --output speech.mp3

import { writeFile } from "node:fs/promises";

const response = await fetch("https://api.paxalabs.com/v1/tts", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.PAXA_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    text: "สวัสดีครับ ยินดีต้อนรับสู่ Paxa Labs",
    voice: "khanomkrok",
    model: "paxa-tts-flash-v2",
    temperature: 0,
  }),
});

if (!response.ok) throw new Error(`TTS failed: ${response.status}`);
await writeFile("speech.mp3", Buffer.from(await response.arrayBuffer()));

import os
import requests

response = requests.post(
    "https://api.paxalabs.com/v1/tts",
    headers={"Authorization": f"Bearer {os.environ['PAXA_API_KEY']}"},
    json={"text": "สวัสดีครับ ยินดีต้อนรับสู่ Paxa Labs", "voice": "khanomkrok", "model": "paxa-tts-flash-v2", "temperature": 0},
)
response.raise_for_status()

with open("speech.mp3", "wb") as f:
    f.write(response.content)

Values#

0 varies least. The same text in the same voice comes back closest in timing and melody from one request to the next. Two requests are not guaranteed to match.
0.5 is the default. An omitted field and 0.5 are one request.
2 varies the reading most.
Values round to the nearest 0.1. A value outside 0 to 2 answers 400 validation.

Designed voices#

On a designed voice, as on any other, lower values hold the voice steadier and higher values vary it more.

Models#

Paxa TTS Flash v2 (paxa-tts-flash-v2) reads temperature. On Paxa TTS Flash (paxa-tts-flash-v1), a value that rounds to 0.5 is accepted, and any other answers 400 validation with path body.temperature and reason not_allowed, before any charge.

Where it is read#

POST /v1/tts.
POST /v1/audio/speech, as a Paxa extension to OpenAI's body. The OpenAI-compatible transcription endpoint ignores its own temperature.
The start frame of WS /v1/tts/live, fixed for the connection. The started event echoes it when it is not 0.5. A start frame whose model refuses it answers an error event with validation, and the connection stays open for a corrected start frame.

Billing and idempotency#

A request costs the same at every temperature. Under an Idempotency-Key, temperature is part of the request: a retry with a different value answers 422 idempotency_mismatch, and an omitted field matches 0.5.

PreviousPauses NextEmotion tags (v1)