gpt-4o-mini-tts

Fined:

• minor · dates — kept the value but never said “july”; a prompt fixes this (8 of 16 transcripts)

→ we sent “Your appointment is on 07/15/2026.”

→ it said “Your appointment. Is on seven fifteen wenty twenty six.”

• minor · dates — kept the value but never said “january”; a prompt fixes this (3 of 5 transcripts)

→ we sent “Renewal falls on 1/1/2027.”

→ it said “Renewal falls on one one. Etwenty twenty seven.”

• 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 'o two.”

• minor · dates — kept the value but never said “march”; a prompt fixes this (5 of 5 transcripts)

→ we sent “Your slot is 03/09 this year.”

→ it said “Your SWAT 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) — said “dash” out loud; a prompt fixes this (3 of 5 transcripts)

→ we sent “The order shipped on 2026-03-09.”

→ it said “The order shipped on two thousand twenty-six dash zero three dash zero nine.”

• minor · dates (international, ×0.4) — kept the value but never said “june”; a prompt fixes this (5 of 5 transcripts)

→ we sent “The lease ends 2025/06/30.”

→ it said “The lease ends twenty twenty five six thirty.”

Token-billed: $0.60/1M text in, $12/1M audio out; OpenAI publishes no per-character or per-minute rate. At ~25 audio tokens/sec (not OpenAI-published) and 900 chars/min, ~$20 per 1M chars. Legacy tts-1 is $15, tts-1-hd $30 per 1M chars.