Training machine offline · last report yesterday

Voice training runs

Sanskrit text-to-speech. The goal is two voices of our own: one that chants verse by its metre, one that reads prose. Daily Sanskrit already chants with Vāgdhenu by Prathosh A P (IISc), credited there. No audio from these experiments is published.

Headline score: Letter error, bench · lower is better Each render is transcribed by the Su-śrotā Sanskrit speech recogniser and compared letter by letter with its text: 0.04 means 4% of letters. Mean over the bench: 30 held-out chanted verses and the bake-off's 14 verse lines. The verses' own human recordings score 0.011 on it.Letter error rate: the share of letters that come out wrong, as a fraction (0.0096 means 0.96% of letters): for OCR, letters read off a page; for a voice, letters a speech recogniser hears in its audio. Lower is better.

Every score on this track
Letter error, bench (lower is better)
Each render is transcribed by the Su-śrotā Sanskrit speech recogniser and compared letter by letter with its text: 0.04 means 4% of letters. Mean over the bench: 30 held-out chanted verses and the bake-off's 14 verse lines. The verses' own human recordings score 0.011 on it.
Letter error, whole bake-off (lower is better)
Letter error over all 30 bake-off lines: verse, prose and hard cases (single words, clusters, visarga).
Letter error, bake-off verses (lower is better)
The same letter error on the bake-off's 14 verse lines only, so runs compare directly with the bake-off models.
ā/a length ratio (higher is better)
How much longer a long ā lasts than a short a, by forced alignment of the known text (median, inside words). Sanskrit wants about 2: people reading measure 2.17 here; most models say long vowels too short.

Progress

Lower is better on the headline.

Best Letter error, bench over time

Each dot is a scored run, placed at the day it ended; the line is the best score so far. Numbered lines are this track's milestones, listed below.

Milestones
  1. 9 Oct 2026 · TTS-E1: the first Sanskrit text-to-speech fine-tune starts on a cloud GPU
  2. 8 Oct 2026 · Voice bake-off: open Sanskrit text-to-speech models scored for letter error and vowel length

Reference models

Other models measured on the same sets, for comparison. Notes say how they were measured.

Method. The bake-off: 30 Sanskrit lines (14 verse, 6 prose, 10 hard cases), one take per model, transcribed by the Su-śrotā recogniser and compared letter by letter; vowel length by forced alignment of the known text.

Reference models scored on the Voice track's test sets
ModelLetter error, whole bake-offLetter error, bake-off versesā/a length ratio
OmniVoice Lowest letter error in the bake-off, but its long vowels come out short.0.04080.00911.67
Vāgdhenu By Prathosh A P (IISc). The only model with human-like vowel length; Daily Sanskrit chants with it, credited there.0.04240.01352.2
Svara v1 Fewest errors by sound class (long vowels, visarga, aspirates).0.05280.01861.75
Indic-Mio0.05850.02361.75
vits_rasa_13 Small and fast enough for a phone. Trained on Rasa prose, so its long vowels are as short as that reader's.0.09520.06241.5
Indic Parler-TTS Sampled output: takes of the same line vary by several points.0.09890.04681.5
Indic-Speak Some takes ran on past the end of the text.0.10010.05371.8
SPRING_F5 Drops words and the starts of words, and speaks too fast.0.16640.17461.33
IndicF5 (base) The base model the Vāgdhenu recipe fine-tunes. Before that fine-tune it does not speak Sanskrit.0.64670.6492—
People reading Real speech, not a model: 60 recorded phrases measured the same way. The yardstick for vowel length.——2.17

Voice runs

Published · 8 runs

All Voice runs. Column headers sort the table.
Data
TTS-E4
tts_e4a_jaya
9 Oct 2026 IndicF5 Archival recitation (non-Vedic), 3.3 h, 3.3 h 4.09 $5.32 — 0.0198 0.0302 2.14
TTS-E3
tts_e3_v3
9 Oct 2026 IndicF5 Vāgdhenu + Rasa prose, 13.9 h 5.33 $6.92 — 0.007 0.0048 2.2
TTS-E2
tts_e2_multi_b
9 Oct 2026 IndicF5 Vāgdhenu + Su-śrotā scholars, 10.5 h 4.83 $6.29 — 0.0073 0.0075 2.2
TTS-E2 try 1 Failed
tts_e2_multi
9 Oct 2026 IndicF5 Vāgdhenu + Su-śrotā scholars 0.37 $0.48 — — — —
TTS-E1
tts_e1_repro_d
9 Oct 2026 IndicF5 Vāgdhenu chant, 5.2 h 4.13 $5.37 — 0.0072 0.0088 2.2
TTS-E1 try 3 Failed
tts_e1_repro_c
9 Oct 2026 IndicF5 Vāgdhenu chant 0.07 $0.10 — — — —
TTS-E1 try 2 Failed
tts_e1_repro_b
9 Oct 2026 IndicF5 Vāgdhenu chant 0.07 $0.09 — — — —
TTS-E1 try 1 Failed
tts_e1_repro
9 Oct 2026 IndicF5 Vāgdhenu chant 0.07 $0.10 — — — —

Cost “—” means no cloud bill (our own GPU at home) or a cost that was not recorded; “Free” is free cloud compute. GPU-h is GPU hours.