zaphodvox

The zaphodvox python package provides a command-line interface for encoding a text file into synthetic speech audio using a locally-hosted Qwen3-TTS server (the eddie-tts fork of qwen3-tts-api, which wraps the open-weight Qwen3-TTS models).

Installation

"He was clearly a man of many qualities, even if they were mostly bad ones."

Install the latest release from PyPI:

$ pip install zaphodvox
...
Successfully installed zaphodvox-2.1.0...

$ zaphodvox test.txt
Nothing to do... I'd give you advice, but you wouldn't listen. No one ever does.

For the latest unreleased code, install from GitHub instead:

$ pip install git+https://github.com/gumptionthomas/zaphodvox.git

Or clone it and install in editable mode to hack on it:

$ git clone https://github.com/gumptionthomas/zaphodvox.git
$ cd zaphodvox
$ pip install -e .

zaphodvox needs Python 3.10–3.12 (its pinned dependencies don't yet ship wheels for 3.13+, so a newer interpreter will try — and fail — to build them from source; pyenv makes pinning one easy) and a current installation of ffmpeg. To actually synthesize anything, it also needs a running Qwen3-TTS server.

Qwen3-TTS Server

"He didn't know why he had become President of the Galaxy, except that it seemed a fun thing to be."

zaphodvox does no synthesis itself. It talks to a locally-hosted Qwen3-TTS server that exposes an OpenAI-style speech API, so you must have one running before encoding.

The server needs to expose three endpoints:

• POST /v1/audio/speech for built-in preset speakers.
• POST /v1/audio/speech/upload for zero-shot voice cloning.
• POST /v1/audio/speech/design for voices generated from a description.

The reference implementation is eddie-tts — a Windows-friendly fork of cornball-ai/qwen3-tts-api, which in turn serves the open-weight QwenLM/Qwen3-TTS models. Follow Eddie's README to install and run it. The --voice-seed and --voice-temperature options require Eddie — upstream qwen3-tts-api implements neither seed nor temperature, so on that server those flags are silently ignored. The models want an NVIDIA GPU, so a CUDA-capable card is effectively a prerequisite for the server (not for zaphodvox). No API keys or authentication are involved, as the server is expected to be local and trusted.

By default zaphodvox talks to the server at http://127.0.0.1:4123. Override the base URL with the --qwen-url argument or the ZAPHODVOX_QWEN_URL environment variable.

Usage

"I refuse to answer that question on the grounds that I don't know the answer."

Detailed usage information can be printed by running:

zaphodvox --help

Some examples using the following text file (gone-bananas.txt):

This is the first line of text.
This is the next line. By default, each line of text is sent to the server individually.
This is the last line. And this is a sentence that is split
between lines. Ideally, these parts of the sentence would be on the same line.

zaphodvox --encoder=qwen --voice-id=Ryan --encode gone-bananas.txt

Running the above command will encode the text file with the locally-hosted Qwen3-TTS server using the Ryan preset speaker. This will result in the following fragment audio files being created in the current directory (one file for each line of text):

gone-bananas-00000.wav ["This is the first line..."]
gone-bananas-00001.wav ["This is the next line. By default..."]
gone-bananas-00002.wav ["This is the last line. And this is..."]
gone-bananas-00003.wav ["between lines. Ideally, these..."]

In addition to the audio files, a manifest JSON file (gone-bananas-manifest.json) will also be written to the current directory. This file contains information about the fragment audio files encoded, including the text, the relative file name, and the voice used. This manifest file can also be used as input to the command rather than a text file. See the manifest documentation for more information.

Voices: Presets, Clones, and Designs

A Qwen voice is one of: a built-in preset speaker, a zero-shot clone of a reference audio file, or a design generated from a text description. --voice-id (preset), --voice-ref-audio (clone), and --voice-description (design) are mutually exclusive.

To use a preset speaker, pass its name to --voice-id. The available speakers are Vivian, Serena, Uncle_Fu, Dylan, Eric, Ryan, Aiden, Ono_Anna, and Sohee. You can optionally steer the delivery with --voice-instruct and set the language with --voice-language:

zaphodvox --encoder=qwen --voice-id=Eric --voice-instruct="depressed, morose" --encode gone-bananas.txt

The default language is English. Other supported values are Chinese, Japanese, Korean, German, French, Russian, Portuguese, Spanish, and Italian:

zaphodvox --encoder=qwen --voice-id=Dylan --voice-language=French --encode gone-bananas.txt

To clone a voice, pass a reference audio file to --voice-ref-audio instead of a --voice-id:

zaphodvox --encoder=qwen --voice-ref-audio=trillian-sample.wav --encode gone-bananas.txt

Without a transcript, this performs a true zero-shot clone. If you also provide the transcript of the reference audio via --voice-ref-text, the server uses the higher-quality in-context (ICL) clone mode:

zaphodvox --encoder=qwen --voice-ref-audio=trillian-sample.wav --voice-ref-text="Well, hello there." --encode gone-bananas.txt

To design a voice from a natural-language description, pass it to --voice-description:

zaphodvox --encoder=qwen --voice-description="a warm elderly woman, gentle and unhurried" --encode gone-bananas.txt

Note that a designed voice is the least consistent choice for a whole book — the model re-derives the voice from the description on each call. For steady narration, design a voice, audition it, and adopt the best take as a clone (see Auditioning a reference voice below); the clone then anchors every chunk.

The audio output format is wav by default. Use --qwen-audio-format to select wav or mp3:

zaphodvox --encoder=qwen --voice-id=Ryan --qwen-audio-format=mp3 --encode gone-bananas.txt

By default each fragment is synthesized non-deterministically, so a voice can drift in timbre and pacing from chunk to chunk. Pin a fixed RNG seed with --voice-seed to keep a voice consistent across every fragment (and across re-encodes). Combining it with a larger --max-chars gives the steadiest results:

zaphodvox --encoder=qwen --voice-id=Ryan --voice-seed=42 --max-chars=500 --encode gone-bananas.txt

The seed is stored with the voice in the manifest, so re-encoding a fragment reproduces the same audio.

A seed makes a given fragment reproducible, but the model still reads different lines with different energy — that variation is driven by the text itself. --voice-temperature tunes how much the delivery varies from run to run, not how flat or dramatic it is: lower is steadier and more repeatable, higher is more varied. It is not an expressiveness dial — on the same sentence, 0.3 and 1.0 are barely distinguishable by ear. For actual style control, reach for --voice-instruct (preset voices) or --voice-description (designed voices), which move the voice far more than temperature does.

Auditioning a reference voice

"The ships hung in the sky in much the same way that bricks don't."

For the most consistent narration, clone every chunk from a single fixed reference clip rather than relying on a preset or a design. The --audition argument helps you find a good reference: it synthesizes a candidate clip of a preset (--voice-id) or designed (--voice-description) voice for each seed you specify — using the same syntax as --indexes (5, 1-5, 3,9,20) — from a sample sentence you provide:

zaphodvox --encoder=qwen --voice-id=Ryan \
  --voice-instruct="calm narrator, neutral American accent" --voice-temperature=0.6 \
  --audition=1-5 --audition-text="It is a mistake to think you can solve any major problems just with potatoes." \
  --out-dir=refs

This writes ryan-audition-01.wav … ryan-audition-05.wav (the basename defaults to the voice name; files are named by seed), plus a ryan-audition.json index, and prints a table of the candidates. --voice-instruct and --voice-temperature apply to every candidate (only the seed varies), so audition at the same temperature you plan to encode with. Aim for ~10–15 seconds of speech in --audition-text so the clip works well as a reference; a short sample gets a warning. If --audition-text is omitted, the first line of the inputfile is used. (Auditioning seeds 1-5 rather than 0-4 is a fine habit — nothing is special about seed 0, but starting at 1 avoids always judging the same seed-0 take first.)

Listen to the candidates and adopt the one you like with --adopt, giving it a name and a voices file to write to (the audition index is the inputfile):

zaphodvox --adopt=2 --voice-name=Narrator --voices-file=voices.json refs/ryan-audition.json

This adds (or updates) a Narrator clone voice in voices.json that references the chosen candidate clip, carrying over its ref_text, seed, and temperature from the audition. From then on, ZVOX: Narrator (or --voice-name=Narrator) reads with that voice. --voice-seed/--voice-temperature override the carried-over values if given. Auditioning and adopting are each their own mode and can't be combined with --encode/--plan/--concat.

Concatenation

To combine the individual fragment audio files into one, add the --concat argument:

zaphodvox --encoder=qwen --voice-id=Ryan --encode --concat gone-bananas.txt

An additional audio file, gone-bananas.wav, will be saved in the current directory.

Cleaning

Note that there isn't much silence between individual lines of the text file. To add a delay between lines, simply add an extra newline between each line of text. The easiest way to do this is to use the --clean option:

zaphodvox --clean gone-bananas.txt

This command will convert the text file to plain text and attempt to add an extra newline between paragraphs as well as combine sentences that have been split between adjacent lines. It will output the newly "cleaned" text file as gone-bananas-cleaned.txt:

This is the first line of text. It should probably be a paragraph.

This is the next line. By default, each line of text is sent to the server individually.

This is the last line. And this is a sentence that is split between lines. Ideally, these parts of the sentence would be on the same line.

Encode this new file:

zaphodvox --encoder=qwen --voice-id=Ryan --encode --concat gone-bananas-cleaned.txt

Notice that a pause is generated for each empty newline and that the last sentence is no longer split between lines.

The --clean and --encode arguments can be combined in a single call:

zaphodvox --encoder=qwen --voice-id=Ryan --clean --encode --concat gone-bananas.txt

If the --max-chars argument is provided, the cleaning process will guarantee that every line is less than max-chars characters by splitting long lines at sentence boundaries.

The text file will be cleaned before being encoded and concatenated into gone-bananas.wav. The cleaned text file (i.e. gone-bananas-cleaned.txt) will still be created in the current directory.

Proofing

"The Guide is definitive. Reality is frequently inaccurate."

Before encoding, --proof scans the manuscript for issues and writes a report. It is read-only — it never edits your text; you fix things by hand from the report (the findings carry line numbers). The deterministic checks are:

• Spelling — words absent from the dictionary and your project wordlist, grouped by unique word (so 500 occurrences of a character's name are one entry, not 500), with suggestions.
• Repeated characters — runs like **** or ___ (stray markup or OCR artifacts).
• Unusual characters — control characters, replacement characters (U+FFFD), zero-width and non-breaking spaces, and other gremlins.
• Whitespace — trailing whitespace, tabs, and runs of blank lines.

zaphodvox --proof --dict gone-bananas.dict gone-bananas.txt

This writes gone-bananas-proof.json (and prints a table). The project wordlist (--dict, defaulting to [basename].dict) is a plain, version-controllable file of accepted spellings — one word per line, # comments allowed. When the proofer flags a real name or coined word, add it once and it stops being flagged:

zaphodvox --add-word Zaphod Beeblebrox Magrathea --dict gone-bananas.dict

The dictionary language defaults to en (override with --dict-language).

LLM-assisted proofreading

The deterministic checks above catch mechanical issues, but not contextual ones. Point --llm-url at a local OpenAI-compatible LLM server (e.g. LM Studio or Ollama) to add a proofreading pass that also flags homophones (their/there), doubled words, garbled sentences, and inconsistent chapter headers:

zaphodvox --proof --llm-url=http://127.0.0.1:1234 --llm-model=qwen2.5-7b-instruct book.txt

These findings are merged into the same report with source: "llm". Only a local LLM is ever contacted — no cloud service is used. The pass is skipped unless --llm-url (or the ZAPHODVOX_LLM_URL environment variable) is set; --llm-model defaults to the ZAPHODVOX_LLM_MODEL environment variable when not given. Like the deterministic checks, it is advisory: nothing is changed automatically.

Voice Configurations

"I'm so great even I get tongue-tied talking to myself."

Multiple voice configurations can be defined in a JSON file and loaded via the --voices-file argument.

This is an example voice configuration file (voices.json):

{
    "voices": {
        "Marvin": {
            "voice_id": "Eric",
            "language": "English",
            "instruct": "depressed, morose, flat and weary",
            "seed": 7
        },
        "Ford": {
            "voice_id": "Dylan",
            "language": "English",
            "instruct": "wry, casual, neutral American accent",
            "seed": 42
        },
        "Trillian": {
            "ref_audio": "trillian-sample.wav",
            "ref_text": "Well, hello there.",
            "seed": 101
        }
    }
}

Each named voice maps directly to the Qwen voice fields, so the voices file is the natural home for per-voice tuning: give each voice its own instruct (to pin its delivery and accent) and its own seed (so a character sounds like themselves across every chunk, and re-encodes reproduce). Tune a voice on the CLI until it sits right, then park that exact instruct/seed here and forget it. Note that instruct steers preset voices only — for a cloned voice (like Trillian above), the reference clip's own delivery sets the tone.

If a --voices-file is used, inline ZVOX: [name] tags in a text inputfile can specify the voice(s) to be used.

A example multi-voice text file (heart-of-gold.txt):

ZVOX: Marvin
This text will be spoken by the Marvin voice defined in the voices JSON file. That is, it will use the
"Eric" preset speaker with a "depressed, morose" instruction and seed 7.

ZVOX: Ford
This line will be spoken by the Ford voice. That is, it will use the "Dylan" preset speaker with its own
instruction and seed.

This paragraph will also be spoken by the Ford voice as it is still the "current" voice.

ZVOX: Trillian // This is a cloned voice
Finally, this will be read by the Trillian voice, cloned from "trillian-sample.wav". Note that text following a space after the voice name will be ignored.
If a line contains the "ZVOX" tag, it will not be synthesized to speech.

zaphodvox --voices-file=voices.json --encoder=qwen --encode heart-of-gold.txt

The above command will result in the following fragment audio files to be created in the current directory:

heart-of-gold-00000.wav ["This text will be spoken by the..." using "Marvin" voice]
heart-of-gold-00001.wav [silence]
heart-of-gold-00002.wav ["This line will be spoken by the..." using "Ford" voice]
heart-of-gold-00003.wav [silence]
heart-of-gold-00004.wav ["This paragraph will also..." using "Ford" voice]
heart-of-gold-00005.wav [silence]
heart-of-gold-00006.wav ["Finally, this will be read by the..." using "Trillian" voice]
heart-of-gold-00007.wav ["If a line contains the..." using "Trillian" voice]

Qwen Voice Configuration

"He preferred people to be puzzled rather than contemptuous."

The JSON voice configuration follows the CLI "voice" arguments fairly closely. One difference is that CLI defaults don't necessarily apply in all cases.

A voice is either a preset (a built-in speaker named by voice_id) or a clone (a zero-shot clone of the reference audio at ref_audio). Exactly one of voice_id or ref_audio is required.

The fields are:

• voice_id: The built-in preset speaker name (one of Vivian, Serena, Uncle_Fu, Dylan, Eric, Ryan, Aiden, Ono_Anna, Sohee). Mutually exclusive with ref_audio/description.
• language: The language of the text (defaults to English).
• instruct: An optional style/emotion direction for a preset voice (e.g. calm, wry). Ignored for cloned/designed voices.
• ref_audio: The path to a reference audio file to clone. Mutually exclusive with voice_id/description.
• ref_text: The transcript of ref_audio. If set, the higher-quality in-context (ICL) clone mode is used; otherwise a true zero-shot clone is used.
• description: A natural-language description of a voice to design (e.g. a warm elderly woman). Mutually exclusive with voice_id/ref_audio.
• seed: An optional fixed RNG seed. When set, every fragment using this voice is synthesized from the same seed, keeping the voice consistent across chunks and across re-encodes. Defaults to non-deterministic.
• temperature: An optional sampling temperature — how much the delivery varies from run to run (lower is steadier and more repeatable, higher is more varied), not an expressiveness control. Eddie defaults to 0.65 (narration-tuned), lower than Qwen's ~0.9, so moving from upstream qwen3-tts-api to Eddie changes the default output.

A preset example:

{
    "voice_id": "Eric",
    "language": "English",
    "instruct": "depressed, morose",
    "seed": 42
}

A clone example:

{
    "ref_audio": "trillian-sample.wav",
    "ref_text": "Well, hello there."
}

A design example:

{
    "description": "a warm elderly woman, gentle and unhurried",
    "seed": 7,
    "temperature": 0.6
}

Manifest

“If I ever meet myself, I'll hit myself so hard I won't know what's hit me.”

A manifest JSON file is created during the encoding process and can be used as the inputfile instead of a text file. If a manifest file is used, the fragment audio files to be re-encoded can be specified with the --indexes argument.

For example, consider this simple text file (towel.txt):

Don't forget your towel.
And always know where it is.

The file is encoded with this command:

zaphodvox --encoder=qwen --voice-id=Ryan --encode towel.txt

Three files will be created in the current directory: the two fragment audio files (towel-00000.wav and towel-00001.wav) and the manifest file (towel-manifest.json).

Here are the contents of towel-manifest.json:

"fragments":
[
    {
        "text": "Don't forget your towel.",
        "filename": "towel-00000.wav",
        "voice":
        {
            "voice_id": "Ryan",
            "language": "English"
        },
        "silence_duration": null,
        "encoder": "qwen",
        "audio_format": "wav"
    },
    {
        "text": "And always know where it is.",
        "filename": "towel-00001.wav",
        "voice":
        {
            "voice_id": "Ryan",
            "language": "English"
        },
        "silence_duration": null,
        "encoder": "qwen",
        "audio_format": "wav"
    }
]

Note that the fragment filenames are relative to the manifest file's location.

Changes can be made to fragment text, filename, or voice items and the modified manifest file can be used to re-encode only the changes by specifying which fragment indexes to encode.

For example, if the second fragment's text field is modified to remove the initial "And", this command will re-encode only the second fragment audio file in place (i.e. towel-00001.wav):

zaphodvox --encoder=qwen --encode --indexes=1 towel-manifest.json

The --concat argument can also be added when using a manifest file as input. In this case, an attempt will be made to concatenate both the unmodified and newly encoded fragment audio files into one. If any of the files specified in the manifest is missing, the concatenation will fail.

A manifest plan can be created from a text file using the --plan argument:

zaphodvox --encoder=qwen --voice-id=Ryan --plan gone-bananas.txt

The above command will write the manifest plan to gone-bananas-plan.json without doing any encoding. It can be reviewed and edited before being used as input to the command with the --encode argument.

By default, each line of the text file is encoded into its own audio fragment. If the --max-chars argument is provided when generating a plan manifest or encoding a text file, the planning process will attempt to combine multiple lines of text per audio fragment, up to max-chars characters. Larger fragments often encode with better results.