# TGSpeechBox

> TGSpeechBox (iPhone/iPad app by Tamas Geczy.)

- Source: https://appshunter.io/ios/app/tgspeechbox/id6759512621 (this page in markdown: same URL + `.md`)
- Developer: [Tamas Geczy](https://appshunter.io/developer/1879168386)
- Category: Utilities, Productivity
- Price: Free
- Age rating: 4+
- Requires: iOS 16.0 · 33 MB
- Languages: English
- Released: 2026-03-26
- Data updated: 2026-05-15
- User reviews in markdown: https://appshunter.io/ios/app/tgspeechbox/id6759512621/reviews.md

## What is TGSpeechBox?

TGSpeechBox is a high-quality speech synthesizer that works as a system voice with VoiceOver and as a standalone text-to-speech app.
Features:
• 26 languages with natural-sounding speech
• Full VoiceOver integration — use as your primary system voice
• 7 voice presets plus YAML-defined voice profiles
• Deep engine tuning: pitch mode, voice tone, formant sharpness, inflection, tremor, breathiness, and more
• Phoneme editor: fine-tune individual speech sounds with live preview
• Pronunciation dictionary: add custom word pronunciations with IPA override support
• Stress, compound, and character dictionaries for advanced control
• Export and share your customizations
• Adjustable sample rate (11025–44100 Hz)
• Rate override and rate boost for VoiceOver
• Language lock: keep your preferred language regardless of system setting
• Runs entirely on-device — no internet required, no data leaves your phone
TGSpeechBox uses a Klatt-style formant synthesis engine with eSpeak-ng for phoneme generation. It is open source under the MIT license.
Built by a blind developer, designed for accessibility from day one.


## Version history (last 2 releases)

### 3.0.1 — 2026-04-03

This version adds many new features:
- Higher cascade formants F7 (6500 Hz) and F8 (7500 Hz) for spectral presence above F6 (Rabiner 1968 defaults). Nyquist-proximity fade auto-mutes them at low sample rates.
- Parallel F7/F8 resonators for fricative high-frequency presence (amp 0.15/0.07).
- 2x source oversampling for cleaner harmonics at lower sample rates.
- Dual-oscillator chorus for vocal fold asymmetry (VoicingTone V5): chorus depth and variation sliders for natural vocal fold jitter.
- Brown noise aspiration blend: white/brown noise mix by sample rate (44k=100% white, 22k=70/30, 16k=50/50). Fixes aspiration thinness at lower sample rates.
- Glottal sharpness rebalanced for F7/F8 spectral dynamics.

- Transition bandwidth widening after obstruents: decaying BW boost across first 3 micro-frames, scaled by F2 sweep width.
- Word-final stop audibility improved: stop floor 4ms to 6ms, word-final bonus 5ms to 8ms, voiced alveolar softening eased.
- Voiced consonant bandwidths widened for smoother transitions. 
- Rhotic diphthong collapse: vowel+liquid tied pairs (/ER/ in "shared", "scared", "stairs") now collapse into micro-frame diphthongs with proper formant sweep. Previously rendered as two crushed tokens with no glide.
- SQUARE diphthong pairScale 1.40 for the wide F3 sweep (2500 to 1620 Hz).
- Diphthong rate compensation bumped 0.15 to 0.30; onset hold exponent 1.3 to 1.6 for better vowel identity at high rates.
- Fixed diphthong tie bar blocking dialect replacements: eSpeak marks diphthongs with tie bars (e-tied-I) which blocked I-to-I_es substitution. Vowel-vowel tie bars are now stripped early; affricate tie bars preserved. (issue #82, reported by @gregodejesus2)
- New `I_es` parallel formants tuned to Spanish-peripheral [i] target (Quilis 1981, Martinez Celdran): pf1 330, pf2 2150, pf3 2850. Previously carried English-lax values.
- New `U_es` phoneme for Spanish [u] diphthong offglides (/au/, /eu/): F1=340, F2=780. Base /U/ was English-lax (F1=405, F2=900).
- `autoDiphthongOffglideToSemivowel: false` for Spanish to preserve dialect-specific offglide phonemes.
- Geminate /ss/ deduplication from eSpeak number expansion ("200" no longer "dosssientos").

- Fixed "behind a wall" quality at 22050 Hz: disabled oversampling decimation and anti-alias LP at 22050+ Hz. Sharpness raised 2.0 to 3.0. This was the most-reported audio quality issue since v3.0.

### 3.0 — 2026-03-26

No release notes.

## Related topics

[tgspeechbox](https://appshunter.io/ios/topics/tgspeechbox)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-05-15.*