Speak Tts

speak - Text to Speech for Agents

Convert text to natural speech audio using Chatterbox TTS on Apple Silicon.

Prerequisites

Input Sources

Web Articles

lynx -dump -nolist "https://example.com/article" | speak --output article.wav

Converting Formats

Output Modes

Default Behavior

speak article.txt          # → ~/Audio/speak/article.wav (no playback)
speak "Hello"              # → ~/Audio/speak/speak_<timestamp>.wav

Directory Auto-Creation

Always create custom directories first:

mkdir -p ~/.chatter/voices/
mkdir -p ~/Audio/custom/

Voice Cloning

Voice cloning generates speech that matches your vocal characteristics (pitch, tone, cadence) from a short recording.

Quality Expectations

• Output captures general voice characteristics but is not a perfect replica
• Quality depends heavily on sample quality
• 15-25 seconds is optimal (10s minimum, 30s maximum)

Recording Your Voice

Using QuickTime:

1. Open QuickTime Player → File → New Audio Recording
2. Record 20 seconds of clear speech
3. File → Export As → Audio Only (.m4a)
4. Convert to WAV (see below)

Using sox (command line):

# -d = use default microphone
# Recording starts immediately and stops after 25 seconds
sox -d -r 24000 -c 1 ~/.chatter/voices/my_voice.wav trim 0 25

Converting to Required Format

Voice samples MUST be: WAV, 24000 Hz, mono, 10-30 seconds.

# From MP3
ffmpeg -i voice.mp3 -ar 24000 -ac 1 voice.wav

# From M4A (QuickTime)
ffmpeg -i voice.m4a -ar 24000 -ac 1 voice.wav

# Trim to 25 seconds
ffmpeg -i long.wav -t 25 -ar 24000 -ac 1 trimmed.wav

# Check sample properties
ffprobe -i voice.wav 2>&1 | grep -E "Duration|Stream"
# Should show: Duration ~15-25s, 24000 Hz, mono

Using Your Voice

# Create directory
mkdir -p ~/.chatter/voices/

# Move sample
mv voice.wav ~/.chatter/voices/my_voice.wav

# Test
speak "Testing my voice" --voice ~/.chatter/voices/my_voice.wav --stream

# Use for content
speak notes.txt --voice ~/.chatter/voices/my_voice.wav --output presentation.wav

Path requirements:

• ✓ Works: ~/.chatter/voices/my_voice.wav (tilde expanded by shell)
• ✓ Works: /Users/name/.chatter/voices/my_voice.wav
• ✗ Fails: my_voice.wav (relative path)
• ✗ Fails: ./voices/my_voice.wav (relative path)

Voice Sample Tips

Default Voice

When --voice is omitted, a built-in default voice is used:

speak "Hello world" --stream  # Uses default voice

Emotion Tags

Tags produce audible effects (actual sounds), not spoken words:

speak "[sigh] Monday again." --stream
# Output: (sigh sound) "Monday again."

NOT supported: [pause], [whisper] (ignored)

For pauses: Use punctuation: "Wait... let me think."

Batch Processing

mkdir -p ~/Audio/book/
speak ch01.txt ch02.txt ch03.txt --output-dir ~/Audio/book/
# Creates: ch01.wav, ch02.wav, ch03.wav

# With auto-chunking (for long files)
speak chapters/*.txt --output-dir ~/Audio/book/ --auto-chunk

# Skip completed files
speak chapters/*.txt --output-dir ~/Audio/book/ --skip-existing

Auto-Chunk Behavior

When using --auto-chunk with batch processing:

1. Each input file is chunked independently
2. Chunks are generated and automatically concatenated per file
3. Final output: one .wav per input file (e.g., ch01.wav)
4. Intermediate chunks deleted (unless --keep-chunks)

You don't need to manually concatenate chunks — only concatenate final chapter files.

Concatenating Audio

# Explicit order (recommended)
speak concat ch01.wav ch02.wav ch03.wav --output book.wav

# Glob pattern (REQUIRES zero-padded filenames)
speak concat audiobook/*.wav --output book.wav

Zero-Padding Rules

Critical for correct concatenation order:

Why: Shell glob expansion sorts alphabetically. 1, 10, 2 vs 01, 02, 10.

PDF to Audiobook (Complete Workflow)

Step 1: Find Chapter Boundaries

# Preview table of contents
pdftotext -f 1 -l 5 textbook.pdf toc.txt
cat toc.txt  # Note chapter page numbers

# Or search for "Chapter" markers
pdftotext textbook.pdf - | grep -n "Chapter"

Step 2: Extract Chapters (Zero-Padded!)

# For 100-page book with ~10 chapters
pdftotext -f 1 -l 12 -layout textbook.pdf ch01.txt
pdftotext -f 13 -l 25 -layout textbook.pdf ch02.txt
pdftotext -f 26 -l 38 -layout textbook.pdf ch03.txt
# ... continue for all chapters

Step 3: Estimate Time

speak --estimate ch*.txt
# Shows: total audio duration, generation time, storage needed

# Quick estimates:
# 1 page ≈ 2 min audio ≈ 1 min generation
# 100 pages ≈ 200 min audio ≈ 100 min generation ≈ 500 MB

Step 4: Generate Audio

mkdir -p audiobook/
speak ch01.txt ch02.txt ch03.txt --output-dir audiobook/ --auto-chunk
# Creates: audiobook/ch01.wav, audiobook/ch02.wav, audiobook/ch03.wav

Step 5: Concatenate

speak concat audiobook/ch01.wav audiobook/ch02.wav audiobook/ch03.wav --output complete_audiobook.wav
# Or with glob (only if zero-padded):
speak concat audiobook/ch*.wav --output complete_audiobook.wav

PDF Troubleshooting

Multi-Voice Content

mkdir -p podcast/scripts podcast/wav

echo "Welcome to the show." > podcast/scripts/01_host.txt
echo "Thanks for having me." > podcast/scripts/02_guest.txt

speak podcast/scripts/01_host.txt --voice ~/.chatter/voices/host.wav --output podcast/wav/01.wav
speak podcast/scripts/02_guest.txt --voice ~/.chatter/voices/guest.wav --output podcast/wav/02.wav

speak concat podcast/wav/01.wav podcast/wav/02.wav --output podcast.wav

Options Reference

Commands

Performance

Resume Capability

For interrupted long generations:

# Single file with auto-chunk — use --resume
speak long.txt --auto-chunk --output book.wav
# If interrupted, manifest saved at ~/Audio/speak/manifest.json
speak --resume ~/Audio/speak/manifest.json

# Batch processing — use --skip-existing
speak ch*.txt --output-dir audiobook/ --auto-chunk
# If interrupted, re-run same command:
speak ch*.txt --output-dir audiobook/ --auto-chunk --skip-existing

Common Errors

Setup

speak "test"     # Auto-setup on first run (downloads model ~500MB)
speak setup      # Or manual setup
speak health     # Verify everything works

Server Management

Server auto-starts and shuts down after 1 hour idle.

speak health        # Check status
speak daemon kill   # Stop manually