Generates audio from the input text.

The text to generate audio for. The maximum length is 4096 characters.

The voice to use when generating the audio. Supported voices are alloy, echo, fable, onyx, nova, and shimmer. Previews of the voices are available in the Text to speech guide.

The format to audio in. Supported formats are mp3, opus, aac, flac, wav, and pcm.

The speed of the generated audio. Select a value from 0.25 to 4.0. 1.0 is the default.