Deepgram
flux
Measured 2026-07-03
Naturalness
~1550
Win % · 95% CI
—
Drift
25
variance analyzer, 20 repeats, run 2026-09-02T10-00-22-058Z, measured 2026-09-02. Single draw; not comparable with other rows in this column.
Synth p50
106ms
106–148 p50–p90
Mean of two 2026-08-12 sweeps (104/108 p50), n=30 each, concurrency 1, one keep-alive connection, 0 rejected. Anchors in the same sweeps came in 11–26% off their published cells, so the column needs a full re-baseline before these are read against each other.
Robustness
0.41
Fined:
• minor · currency (international, ×0.4) — kept the value but never said “forty five”; a prompt fixes this (7 of 16 transcripts)
→ we sent “Balance: -€45,90 outstanding.”
→ it said “Balance: negative four thousand five hundred and ninety euros outstanding.”
• minor · dates — kept the value but never said “july”; a prompt fixes this (7 of 16 transcripts)
→ we sent “Your appointment is on 07/15/2026.”
→ it said “Your appointment is on zero seven fifteen, twenty twenty six.”
• minor · dates — kept the value but never said “january”; a prompt fixes this (7 of 16 transcripts)
→ we sent “Renewal falls on 1/1/2027.”
→ it said “Renewal falls on one one twenty twenty seven.”
• minor · dates — kept the value but never said “november”; a prompt fixes this (7 of 16 transcripts)
→ we sent “The policy started 11/30/2024.”
→ it said “The policy started eleven thirty, twenty twenty four.”
• minor · dates — kept the value but never said “october”; a prompt fixes this (7 of 16 transcripts)
→ we sent “The deadline moved to 10/02.”
→ it said “The deadline moved to ten zero two.”
• minor · dates — kept the value but never said “march”; a prompt fixes this (3 of 5 transcripts)
→ we sent “Your slot is 03/09 this year.”
→ it said “Your slot is zero three zero nine this year.”
• minor · dates — kept the value but never said “february”; a prompt fixes this (7 of 16 transcripts)
→ we sent “Renewal is 02/29/2024.”
→ it said “Renewal is zero two twenty nine twenty twenty four.”
• minor · dates (international, ×0.4) — kept the value but never said “march”; a prompt fixes this (7 of 16 transcripts)
→ we sent “The order shipped on 2026-03-09.”
→ it said “The order shipped on twenty twenty six zero three zero nine.”
• minor · dates (international, ×0.4) — kept the value but never said “june”; a prompt fixes this (7 of 16 transcripts)
→ we sent “The lease ends 2025/06/30.”
→ it said “The lease ends twenty twenty five zero six thirty.”
• fatal · large numbers — never said “zero zero” (5 of 5 transcripts)
→ we sent “Only 007 seats remain.”
→ it said “Only seven seats remain.”
• minor · math operators — kept the value but never said “minus”; a prompt fixes this (3 of 5 transcripts)
→ we sent “That leaves 10-4=6 remaining.”
→ it said “That leaves ten, four equals six remaining.”
• minor · math operators — kept the value but never said “three quarters”; a prompt fixes this (5 of 5 transcripts)
→ we sent “Give me 3/4 of the batch.”
→ it said “Give me three-four of the batch.”
• fatal · math operators — never said “times” (3 of 5 transcripts)
→ we sent “Check it: 7×8=56, not 54.”
→ it said “Check it. 7 psi equals 56, not 54.”
• fatal · math operators — never said “divided” (5 of 5 transcripts)
→ we sent “That is 100÷4=25 per person.”
→ it said “That is 104 equals 25 per person.”
Cost / 1M chars
$45.0
Deepgram published list, Pay As You Go: $0.0450 per 1,000 characters = $45/1M. Same unit that puts Aura-2 at $0.030/1k = the $30 cell above, so the two are directly comparable — Flux TTS costs 50% more than Aura-2. Growth tier is $0.0405/1k ($40.5/1M). Free to build against through 2026-09-12 (45 concurrent streams globally, 5 EU/AU); billing starts 09-13.
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