Zero-Shot Voice Cloning
Replicate any target voice with 94% similarity using only a 5-second sample, supporting cross-lingual synthesis.
speech-2.5-hd-preview
The text speech 2.5 model by ByteDance offers studio-grade 48kHz audio and native expressive prosody. It supports zero-shot voice cloning and sub-200ms latency, making it ideal for real-time applications and professional content creation at scale.
$ 0
text
$ 60
$ 100
audio
Playground
JSON
API
Input
Core text speech 2.5 Features
Technical highlights that make the 2.5 HD preview model a leader in synthetic voice technology.
Studio-Grade 48kHz Audio
High-definition output designed for broadcasting, providing superior clarity compared to 24kHz standard models.
Sub-200ms Latency
Optimized processing pipeline ensures rapid TTFB, making it the fastest choice for conversational AI applications.
Native Expressive Prosody
The model automatically interprets text context to add natural pauses, sighs, and emotional depth without manual SSML tags.
How to Get a speech-2.5-hd-preview API Key
Getting a speech-2.5-hd-preview API key takes four steps and a few minutes. Create a free GPTProto account, add credits, generate your key, and make your first call — at $0 / $60 it's a cheaper speech-2.5-hd-preview API key than going direct, and one key works across every model on the platform. Full speech-2.5-hd-preview Documentation is in the docs.
Sign up
Create your free GPT Proto account to begin. You can set up an organization for your team at any time.
Top up
Your balance can be used across all models on the platform, including speech-2.5-hd-preview, giving you the flexibility to experiment and scale as needed.
Generate your API key
In your dashboard, create an API key — you'll need it to authenticate when making requests to speech-2.5-hd-preview.
Make your first API call
Use your API key with our sample code to send a request to speech-2.5-hd-preview via GPT Proto and see instant AI-powered results.
text speech 2.5 FAQ
Common questions about integrating text speech 2.5 into your applications for high-quality audio production.
What is the typical latency for text speech 2.5 requests?
The model is optimized for high-speed performance, delivering a Time To First Byte (TTFB) of approximately 180ms. This makes the text speech 2.5 model significantly faster than OpenAI TTS-1-HD, providing a seamless experience for real-time voice assistants and interactive applications that require immediate verbal feedback.
How long of an audio sample is needed for voice cloning?
To achieve high-fidelity zero-shot voice cloning, you only need a 5 to 10-second audio reference. The text speech 2.5 system uses this sample to extract vocal characteristics, allowing the cloned voice to read any text input with high similarity (94.1%) across 30+ supported languages while maintaining the original speaker's identity.
Does text speech 2.5 support high-definition output?
Yes, it supports studio-grade 48kHz output in various formats including MP3, WAV, PCM, and Opus. This resolution is superior to the 24kHz industry standard, ensuring that synthesized speech sounds professional and clear, which is essential for podcasts, audiobooks, and high-end digital human animations.
What are the input limits for text synthesis?
Each individual request can process text up to 4,096 characters. For longer documents or extensive scripts, we recommend chunking the text into smaller segments. This prevents processing timeouts and ensures the neural engine maintains consistent prosody and emotional inflection throughout the entire audio generation process.
Is my text data used to train the underlying models?
Privacy is a core priority. Any text or audio samples sent through our API to the text speech 2.5 preview model are excluded from ByteDance's training datasets by default. Your proprietary scripts and voice cloning data remain secure and are used solely for generating your specific request outputs.
How does pricing work for HD and cloned voices?
Standard voice synthesis is priced at $15.00 per 1 million characters. For high-definition or cloned voices, the rate is $30.00 per 1 million characters. GPTProto.com provides unified billing, allowing you to access these advanced features without managing multiple separate enterprise contracts with individual vendors.
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